diff --git a/spring-data-mongodb-distribution/pom.xml b/spring-data-mongodb-distribution/pom.xml index 90e912f67..e9278f846 100644 --- a/spring-data-mongodb-distribution/pom.xml +++ b/spring-data-mongodb-distribution/pom.xml @@ -2,7 +2,7 @@ 4.0.0 - + spring-data-mongodb-distribution pom @@ -16,7 +16,7 @@ 1.6.0.BUILD-SNAPSHOT ../pom.xml - + ${basedir}/.. SDMONGO @@ -32,6 +32,10 @@ org.codehaus.mojo wagon-maven-plugin + + org.asciidoctor + asciidoctor-maven-plugin + diff --git a/src/docbkx/index.xml b/src/docbkx/index.xml deleted file mode 100644 index 8f159a478..000000000 --- a/src/docbkx/index.xml +++ /dev/null @@ -1,99 +0,0 @@ - - - - - Spring Data MongoDB - Reference Documentation - - &version; - - - - Mark - Pollack - - - - Thomas - Risberg - - - - Oliver - Gierke - - - Costin - Leau - - - Jon - Brisbin - - - Thomas - Darimont - - - Christoph - Strobl - - - - - Copies of this document may be made for your own use and for - distribution to others, provided that you do not charge any fee for such - copies and further provided that each copy contains this Copyright - Notice, whether distributed in print or electronically. - - - - - - 2008-2014 - - The original authors. - - - Spring Data MongoDB - Reference Documentation - - - - - - - - Introduction - - - - - - - - - - - Reference Documentation - - - - - - - - - - - - Appendix - - - - - - - - - - diff --git a/src/docbkx/introduction/getting-started.xml b/src/docbkx/introduction/getting-started.xml deleted file mode 100644 index cdcc8f8b5..000000000 --- a/src/docbkx/introduction/getting-started.xml +++ /dev/null @@ -1,63 +0,0 @@ - - - - Additional Help Resources - - Learning a new framework is not always straight forward. In this - section, we try to provide what we think is an easy to follow guide for - starting with Spring Data Document module. However, if you encounter issues - or you are just looking for an advice, feel free to use one of the links - below: - -
- Support - - There are a few support options available: - -
- Community Forum - - Spring Data on Stackoverflow Stackoverflow - is a tag for all Spring Data (not just Document) users to share - information and help each other. Note that registration is needed - only for posting. -
- -
- Professional Support - - Professional, from-the-source support, with guaranteed response - time, is available from Pivotal - Sofware, Inc., the company behind Spring Data and Spring. -
-
- -
- Following Development - - For information on the Spring Data Mongo source code repository, - nightly builds and snapshot artifacts please see the Spring Data Mongo - homepage. - - You can help make Spring Data best serve the needs of the Spring - community by interacting with developers through the Community on Stackoverflow. - To follow developer activity look for the mailing list information on the - Spring Data Mongo homepage. - - If you encounter a bug or want to suggest an improvement, please - create a ticket on the Spring Data issue tracker. - - To stay up to date with the latest news and announcements in the - Spring eco system, subscribe to the Spring Community Portal. - - Lastly, you can follow the SpringSource Data blog or the project team on Twitter - (SpringData). -
- diff --git a/src/docbkx/introduction/introduction.xml b/src/docbkx/introduction/introduction.xml deleted file mode 100644 index 7684a1259..000000000 --- a/src/docbkx/introduction/introduction.xml +++ /dev/null @@ -1,95 +0,0 @@ - - - - This document is the reference guide for Spring Data - Document - Support. It explains Document module concepts and semantics and the syntax - for various stores namespaces. This section provides some basic - introduction to Spring and Document database. The rest of the document - refers only to Spring Data Document features and assumes the user is - familiar with document databases such as MongoDB and CouchDB as well as - Spring concepts.
- Knowing Spring - - Spring Data uses Spring framework's core - functionality, such as the IoC - container, type - conversion system, expression - language, JMX - integration, and portable DAO - exception hierarchy. While it is not important to know the - Spring APIs, understanding the concepts behind them is. At a minimum, - the idea behind IoC should be familiar for whatever IoC container you - choose to use. - - The core functionality of the MongoDB and CouchDB support can be - used directly, with no need to invoke the IoC services of the Spring - Container. This is much like JdbcTemplate which - can be used 'standalone' without any other services of the Spring - container. To leverage all the features of Spring Data document, such as - the repository support, you will need to configure some parts of the - library using Spring. - - To learn more about Spring, you can refer to the comprehensive - (and sometimes disarming) documentation that explains in detail the - Spring Framework. There are a lot of articles, blog entries and books on - the matter - take a look at the Spring framework home page for - more information. -
- Knowing NoSQL and Document databases - - NoSQL stores have taken the storage world by storm. It is a vast - domain with a plethora of solutions, terms and patterns (to make things - worth even the term itself has multiple meanings). - While some of the principles are common, it is crucial that the user is - familiar to some degree with the stores supported by DATADOC. The best - way to get acquainted to this solutions is to read their documentation - and follow their examples - it usually doesn't take more then 5-10 - minutes to go through them and if you are coming from an RDMBS-only - background many times these exercises can be an eye opener. - - The jumping off ground for learning about MongoDB is www.mongodb.org. Here is a list of - other useful resources. - - - - The manual introduces MongoDB and contains links to - getting started guides, reference documentation and tutorials. - - - - The online shell - provides a convenient way to interact with a MongoDB instance in - combination with the online tutorial. - - - - MongoDB Java - Language Center - - - - Several books - available for purchase - - - - Karl Seguin's online book: "The Little MongoDB - Book" - - -
- diff --git a/src/docbkx/introduction/requirements.xml b/src/docbkx/introduction/requirements.xml deleted file mode 100644 index 8640ce9d1..000000000 --- a/src/docbkx/introduction/requirements.xml +++ /dev/null @@ -1,14 +0,0 @@ - - Requirements - - Spring Data MongoDB 1.x binaries requires JDK level 6.0 and above, - and - Spring Framework - 3.2.x and above. - - - In terms of document stores, - MongoDB - preferably version 2.4. - - \ No newline at end of file diff --git a/src/docbkx/preface.xml b/src/docbkx/preface.xml deleted file mode 100644 index 6d769ac1d..000000000 --- a/src/docbkx/preface.xml +++ /dev/null @@ -1,13 +0,0 @@ - - - - Preface - - The Spring Data MongoDB project applies core Spring concepts to - the development of solutions using the MongoDB document style data store. - We provide a "template" as a high-level abstraction for storing and querying - documents. You will notice similarities to the JDBC support in the Spring - Framework. - - diff --git a/src/docbkx/reference/cross-store.xml b/src/docbkx/reference/cross-store.xml deleted file mode 100644 index 510d8d4c5..000000000 --- a/src/docbkx/reference/cross-store.xml +++ /dev/null @@ -1,293 +0,0 @@ - - - - Cross Store support - - Sometimes you need to store data in multiple data stores and these - data stores can be of different types. One might be relational while the - other a document store. For this use case we have created a separate module - in the MongoDB support that handles what we call cross-store support. The - current implementation is based on JPA as the driver for the relational - database and we allow select fields in the Entities to be stored in a Mongo - database. In addition to allowing you to store your data in two stores we - also coordinate persistence operations for the non-transactional MongoDB - store with the transaction life-cycle for the relational database. - -
- Cross Store Configuration - - Assuming that you have a working JPA application and would like to - add some cross-store persistence for MongoDB. What do you have to add to - your configuration? - - First of all you need to add a dependency on the - spring-data-mongodb-cross-store module. Using Maven - this is done by adding a dependency to your pom: - - - Example Maven pom.xml with spring-data-mongodb-cross-store - dependency - - <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> - <modelVersion>4.0.0</modelVersion> - -... - - <!-- Spring Data --> - <dependency> - <groupId>org.springframework.data</groupId> - <artifactId>spring-data-mongodb-cross-store</artifactId> - <version>${spring.data.mongo.version}</version> - </dependency> - - -... - -</project> - - - - Once this is done we need to enable AspectJ for the project. The - cross-store support is implemented using AspectJ aspects so by enabling - compile time AspectJ support the cross-store features will become - available to your project. In Maven you would add an additional plugin to - the <build> section of the pom: - - - Example Maven pom.xml with AspectJ plugin enabled - - <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> - <modelVersion>4.0.0</modelVersion> - -... - - <build> - <plugins> - - ... - - <plugin> - <groupId>org.codehaus.mojo</groupId> - <artifactId>aspectj-maven-plugin</artifactId> - <version>1.0</version> - <dependencies> - <!-- NB: You must use Maven 2.0.9 or above or these are ignored (see MNG-2972) --> - <dependency> - <groupId>org.aspectj</groupId> - <artifactId>aspectjrt</artifactId> - <version>${aspectj.version}</version> - </dependency> - <dependency> - <groupId>org.aspectj</groupId> - <artifactId>aspectjtools</artifactId> - <version>${aspectj.version}</version> - </dependency> - </dependencies> - <executions> - <execution> - <goals> - <goal>compile</goal> - <goal>test-compile</goal> - </goals> - </execution> - </executions> - <configuration> - <outxml>true</outxml> - <aspectLibraries> - <aspectLibrary> - <groupId>org.springframework</groupId> - <artifactId>spring-aspects</artifactId> - </aspectLibrary> - <aspectLibrary> - <groupId>org.springframework.data</groupId> - <artifactId>spring-data-mongodb-cross-store</artifactId> - </aspectLibrary> - </aspectLibraries> - <source>1.6</source> - <target>1.6</target> - </configuration> - </plugin> - - ... - - </plugins> - </build> - -... - -</project> - - - - Finally, you need to configure your project to use MongoDB and also - configure the aspects that are used. The following XML snippet should be - added to your application context: - - - Example application context with MongoDB and cross-store aspect - support - - <?xml version="1.0" encoding="UTF-8"?> -<beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:jdbc="http://www.springframework.org/schema/jdbc" - xmlns:jpa="http://www.springframework.org/schema/data/jpa" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation="http://www.springframework.org/schema/data/mongo - http://www.springframework.org/schema/data/mongo/spring-mongo.xsd - http://www.springframework.org/schema/jdbc - http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd - http://www.springframework.org/schema/beans - http://www.springframework.org/schema/beans/spring-beans-3.0.xsd - http://www.springframework.org/schema/data/jpa - http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd"> - - ... - - <!-- Mongo config --> - <mongo:mongo host="localhost" port="27017"/> - - <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg name="mongo" ref="mongo"/> - <constructor-arg name="databaseName" value="test"/> - <constructor-arg name="defaultCollectionName" value="cross-store"/> - </bean> - - <bean class="org.springframework.data.mongodb.core.MongoExceptionTranslator"/> - - <!-- Mongo cross-store aspect config --> - <bean class="org.springframework.data.persistence.document.mongo.MongoDocumentBacking" - factory-method="aspectOf"> - <property name="changeSetPersister" ref="mongoChangeSetPersister"/> - </bean> - <bean id="mongoChangeSetPersister" - class="org.springframework.data.persistence.document.mongo.MongoChangeSetPersister"> - <property name="mongoTemplate" ref="mongoTemplate"/> - <property name="entityManagerFactory" ref="entityManagerFactory"/> - </bean> - - ... - -</beans> - - - - - - -
- -
- Writing the Cross Store Application - - We are assuming that you have a working JPA application so we will - only cover the additional steps needed to persist part of your Entity in - your Mongo database. First you need to identify the field you want - persisted. It should be a domain class and follow the general rules for the - Mongo mapping support covered in previous chapters. The field you want - persisted in MongoDB should be annotated using the - @RelatedDocument annotation. That is really all you - need to do!. The cross-store aspects take care of the rest. This includes - marking the field with @Transient so it won't be persisted using JPA, - keeping track of any changes made to the field value and writing them to - the database on successful transaction completion, loading the document - from MongoDB the first time the value is used in your application. Here is - an example of a simple Entity that has a field annotated with - @RelatedEntity. - - - Example of Entity with @RelatedDocument - - @Entity -public class Customer { - - @Id - @GeneratedValue(strategy = GenerationType.IDENTITY) - private Long id; - - private String firstName; - - private String lastName; - - @RelatedDocument - private SurveyInfo surveyInfo; - - // getters and setters omitted - -} - - - - Example of domain class to be stored as document - - public class SurveyInfo { - - private Map<String, String> questionsAndAnswers; - - public SurveyInfo() { - this.questionsAndAnswers = new HashMap<String, String>(); - } - - public SurveyInfo(Map<String, String> questionsAndAnswers) { - this.questionsAndAnswers = questionsAndAnswers; - } - - public Map<String, String> getQuestionsAndAnswers() { - return questionsAndAnswers; - } - - public void setQuestionsAndAnswers(Map<String, String> questionsAndAnswers) { - this.questionsAndAnswers = questionsAndAnswers; - } - - public SurveyInfo addQuestionAndAnswer(String question, String answer) { - this.questionsAndAnswers.put(question, answer); - return this; - } -} - - - Once the SurveyInfo has been set on the Customer object above the - MongoTemplate that was configured above is used to save the SurveyInfo - along with some metadata about the JPA Entity is stored in a MongoDB - collection named after the fully qualified name of the JPA Entity class. - The following code: - - - Example of code using the JPA Entity configured for cross-store - persistence - - Customer customer = new Customer(); - customer.setFirstName("Sven"); - customer.setLastName("Olafsen"); - SurveyInfo surveyInfo = new SurveyInfo() - .addQuestionAndAnswer("age", "22") - .addQuestionAndAnswer("married", "Yes") - .addQuestionAndAnswer("citizenship", "Norwegian"); - customer.setSurveyInfo(surveyInfo); - customerRepository.save(customer); - - - - Executing the code above results in the following JSON document - stored in MongoDB. - - - Example of JSON document stored in MongoDB - - { "_id" : ObjectId( "4d9e8b6e3c55287f87d4b79e" ), - "_entity_id" : 1, - "_entity_class" : "org.springframework.data.mongodb.examples.custsvc.domain.Customer", - "_entity_field_name" : "surveyInfo", - "questionsAndAnswers" : { "married" : "Yes", - "age" : "22", - "citizenship" : "Norwegian" }, - "_entity_field_class" : "org.springframework.data.mongodb.examples.custsvc.domain.SurveyInfo" } - - - -
- diff --git a/src/docbkx/reference/introduction.xml b/src/docbkx/reference/introduction.xml deleted file mode 100644 index 3e202eb5d..000000000 --- a/src/docbkx/reference/introduction.xml +++ /dev/null @@ -1,21 +0,0 @@ - - - - Document Structure - - This part of the reference documentation explains the core functionality - offered by Spring Data Document. - - - - - introduces the MongoDB module feature set. - - - - - introduces the repository support for MongoDB. - - - \ No newline at end of file diff --git a/src/docbkx/reference/jmx.xml b/src/docbkx/reference/jmx.xml deleted file mode 100644 index 00e9b75ea..000000000 --- a/src/docbkx/reference/jmx.xml +++ /dev/null @@ -1,109 +0,0 @@ - - - - JMX support - - The JMX support for MongoDB exposes the results of executing the - 'serverStatus' command on the admin database for a single MongoDB server - instance. It also exposes an administrative MBean, MongoAdmin which will let - you perform administrative operations such as drop or create a database. The - JMX features build upon the JMX feature set available in the Spring - Framework. See here - for more details. - -
- MongoDB JMX Configuration - - Spring's Mongo namespace enables you to easily enable JMX - functionality - - - XML schema to configure MongoDB - - <?xml version="1.0" encoding="UTF-8"?> - <beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:context="http://www.springframework.org/schema/context" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation= - "http://www.springframework.org/schema/context - http://www.springframework.org/schema/context/spring-context-3.0.xsd - http://www.springframework.org/schema/data/mongo - http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd - http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> - -<beans> - - <!-- Default bean name is 'mongo' --> - <mongo:mongo host="localhost" port="27017"/> - - <!-- by default look for a Mongo object named 'mongo' --> - <mongo:jmx/> - - <context:mbean-export/> - - <!-- To translate any MongoExceptions thrown in @Repository annotated classes --> - <context:annotation-config/> - - <bean id="registry" class="org.springframework.remoting.rmi.RmiRegistryFactoryBean" p:port="1099" /> - - <!-- Expose JMX over RMI --> - <bean id="serverConnector" class="org.springframework.jmx.support.ConnectorServerFactoryBean" - depends-on="registry" - p:objectName="connector:name=rmi" - p:serviceUrl="service:jmx:rmi://localhost/jndi/rmi://localhost:1099/myconnector" /> - -</beans> - - - This will expose several MBeans - - - - AssertMetrics - - - - BackgroundFlushingMetrics - - - - BtreeIndexCounters - - - - ConnectionMetrics - - - - GlobalLoclMetrics - - - - MemoryMetrics - - - - OperationCounters - - - - ServerInfo - - - - MongoAdmin - - - - This is shown below in a screenshot from JConsole - - - - - - -
- diff --git a/src/docbkx/reference/logging.xml b/src/docbkx/reference/logging.xml deleted file mode 100644 index 5c129f00d..000000000 --- a/src/docbkx/reference/logging.xml +++ /dev/null @@ -1,44 +0,0 @@ - - - - Logging support - - An appender for Log4j is provided in the maven module - "spring-data-mongodb-log4j". Note, there is no dependency on other Spring - Mongo modules, only the MongoDB driver. - -
- MongoDB Log4j Configuration - - Here is an example configuration - - log4j.rootCategory=INFO, stdout - -log4j.appender.stdout=org.springframework.data.document.mongodb.log4j.MongoLog4jAppender -log4j.appender.stdout.layout=org.apache.log4j.PatternLayout -log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - <%m>%n -log4j.appender.stdout.host = localhost -log4j.appender.stdout.port = 27017 -log4j.appender.stdout.database = logs -log4j.appender.stdout.collectionPattern = %X{year}%X{month} -log4j.appender.stdout.applicationId = my.application -log4j.appender.stdout.warnOrHigherWriteConcern = FSYNC_SAFE - -log4j.category.org.apache.activemq=ERROR -log4j.category.org.springframework.batch=DEBUG -log4j.category.org.springframework.data.document.mongodb=DEBUG -log4j.category.org.springframework.transaction=INFO - - The important configuration to look at aside from host and port is - the database and collectionPattern. The variables year, month, day and - hour are available for you to use in forming a collection name. This is to - support the common convention of grouping log information in a collection - that corresponds to a specific time period, for example a collection per - day. - - There is also an applicationId which is put into the stored message. - The document stored from logging as the following keys: level, name, - applicationId, timestamp, properties, traceback, and message. -
- diff --git a/src/docbkx/reference/mapping.xml b/src/docbkx/reference/mapping.xml deleted file mode 100644 index 41fb77e39..000000000 --- a/src/docbkx/reference/mapping.xml +++ /dev/null @@ -1,744 +0,0 @@ - - - - Mapping - - Rich mapping support is provided by the - MongoMappingConverter. - MongoMappingConverter has a rich metadata model that - provides a full feature set of functionality to map domain objects to - MongoDB documents.The mapping metadata model is populated using annotations - on your domain objects. However, the infrastructure is not limited to using - annotations as the only source of metadata information. The - MongoMappingConverter also allows you to map objects - to documents without providing any additional metadata, by following a set - of conventions. - - In this section we will describe the features of the - MongoMappingConverter. How to use conventions for mapping objects to - documents and how to override those conventions with annotation based - mapping metadata. - - - SimpleMongoConverter has been deprecated in - Spring Data MongoDB M3 as all of its functionality has been subsumed into - MappingMongoConverter. - - -
- Convention based Mapping - - MongoMappingConverter has a few conventions - for mapping objects to documents when no additional mapping metadata is - provided. The conventions are: - - - - The short Java class name is mapped to the collection name in - the following manner. The class - 'com.bigbank.SavingsAccount' maps to - 'savingsAccount' collection name. - - - - All nested objects are stored as nested objects in the document - and *not* as DBRefs - - - - The converter will use any Spring Converters registered with it - to override the default mapping of object properties to document - field/values. - - - - The fields of an object are used to convert to and from fields - in the document. Public JavaBean properties are not used. - - - - You can have a single non-zero argument constructor whose - constructor argument names match top level field names of document, - that constructor will be used. Otherwise the zero arg constructor will - be used. if there is more than one non-zero argument constructor an - exception will be thrown. - - - -
- How the '_id' field is handled in the mapping layer - - MongoDB requires that you have an '_id' field for all documents. - If you don't provide one the driver will assign a ObjectId with a - generated value. The "_id" field can be of any type the, other than - arrays, so long as it is unique. The driver naturally supports all - primitive types and Dates. When using the - MongoMappingConverter there are certain rules - that govern how properties from the Java class is mapped to this '_id' - field. - - The following outlines what field will be mapped to the '_id' - document field: - - - - A field annotated with @Id - (org.springframework.data.annotation.Id) - will be mapped to the '_id' field. - - - - A field without an annotation but named - id will be mapped to the '_id' - field. - - - - The following outlines what type conversion, if any, will be done - on the property mapped to the _id document field. - - - - If a field named 'id' is declared as a String or BigInteger in - the Java class it will be converted to and stored as an ObjectId if - possible. ObjectId as a field type is also valid. If you specify a - value for 'id' in your application, the conversion to an ObjectId is - detected to the MongoDBdriver. If the specified 'id' value cannot be - converted to an ObjectId, then the value will be stored as is in the - document's _id field. - - - - If a field named ' id' id field is not declared as a String, - BigInteger, or ObjectID in the Java class then you should assign it - a value in your application so it can be stored 'as-is' in the - document's _id field. - - - - If no field named 'id' is present in the Java class then an - implicit '_id' file will be generated by the driver but not mapped - to a property or field of the Java class. - - - - When querying and updating MongoTemplate - will use the converter to handle conversions of the - Query and Update objects - that correspond to the above rules for saving documents so field names - and types used in your queries will be able to match what is in your - domain classes. -
-
- -
- Mapping Configuration - - Unless explicitly configured, an instance of - MongoMappingConverter is created by default when - creating a MongoTemplate. You can create your own - instance of the MappingMongoConverter so as to tell - it where to scan the classpath at startup your domain classes in order to - extract metadata and construct indexes. Also, by creating your own - instance you can register Spring converters to use for mapping specific - classes to and from the database. - - You can configure the MongoMappingConverter - as well as com.mongodb.Mongo and MongoTemplate - either using Java or XML based metadata. Here is an example using Spring's - Java based configuration - - - @Configuration class to configure MongoDB mapping support - - @Configuration -public class GeoSpatialAppConfig extends AbstractMongoConfiguration { - - @Bean - public Mongo mongo() throws Exception { - return new Mongo("localhost"); - } - - @Override - public String getDatabaseName() { - return "database"; - } - - @Override - public String getMappingBasePackage() { - return "com.bigbank.domain"; - } - - // the following are optional - - - @Bean - @Override - public CustomConversions customConversions() throws Exception { - List<Converter<?, ?>> converterList = new ArrayList<Converter<?, ?>>(); - converterList.add(new org.springframework.data.mongodb.test.PersonReadConverter()); - converterList.add(new org.springframework.data.mongodb.test.PersonWriteConverter()); - return new CustomConversions(converterList); - } - - @Bean - public LoggingEventListener<MongoMappingEvent> mappingEventsListener() { - return new LoggingEventListener<MongoMappingEvent>(); - } - -} - - - AbstractMongoConfiguration requires you to - implement methods that define a com.mongodb.Mongo - as well as provide a database name. - AbstractMongoConfiguration also has a method you - can override named 'getMappingBasePackage' which - tells the converter where to scan for classes annotated with the - @org.springframework.data.mongodb.core.mapping.Document - annotation. - - You can add additional converters to the converter by overriding the - method afterMappingMongoConverterCreation. Also shown in the above example - is a LoggingEventListener which logs - MongoMappingEvents that are posted onto Spring's - ApplicationContextEvent - infrastructure. - - - AbstractMongoConfiguration will create a MongoTemplate instance - and registered with the container under the name 'mongoTemplate'. - - - You can also override the method UserCredentials - getUserCredentials() to provide the username and password - information to connect to the database. - - Spring's MongoDB namespace enables you to easily enable mapping - functionality in XML - - - XML schema to configure MongoDB mapping support - - <?xml version="1.0" encoding="UTF-8"?> -<beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:context="http://www.springframework.org/schema/context" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation="http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd - http://www.springframework.org/schema/data/mongo http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd - http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> - - <!-- Default bean name is 'mongo' --> - <mongo:mongo host="localhost" port="27017"/> - - <mongo:db-factory dbname="database" mongo-ref="mongo"/> - - <!-- by default look for a Mongo object named 'mongo' - default name used for the converter is 'mappingConverter' --> - <mongo:mapping-converter base-package="com.bigbank.domain"> - <mongo:custom-converters> - <mongo:converter ref="readConverter"/> - <mongo:converter> - <bean class="org.springframework.data.mongodb.test.PersonWriteConverter"/> - </mongo:converter> - </mongo:custom-converters> - </mongo:mapping-converter> - - <bean id="readConverter" class="org.springframework.data.mongodb.test.PersonReadConverter"/> - - <!-- set the mapping converter to be used by the MongoTemplate --> - <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg name="mongoDbFactory" ref="mongoDbFactory"/> - <constructor-arg name="mongoConverter" ref="mappingConverter"/> - </bean> - - <bean class="org.springframework.data.mongodb.core.mapping.event.LoggingEventListener"/> - -</beans - - - - The base-package property tells it where to scan for - classes annotated with the - @org.springframework.data.mongodb.core.mapping.Document - annotation. -
- -
- Metadata based Mapping - - To take full advantage of the object mapping functionality inside - the Spring Data/MongoDB support, you should annotate your mapped objects - with the - @org.springframework.data.mongodb.core.mapping.Document - annotation. Although it is not necessary for the mapping framework to have - this annotation (your POJOs will be mapped correctly, even without any - annotations), it allows the classpath scanner to find and pre-process your - domain objects to extract the necessary metadata. If you don't use this - annotation, your application will take a slight performance hit the first - time you store a domain object because the mapping framework needs to - build up its internal metadata model so it knows about the properties of - your domain object and how to persist them. - - - Example domain object - - package com.mycompany.domain; - -@Document -public class Person { - - @Id - private ObjectId id; - - @Indexed - private Integer ssn; - - private String firstName; - - @Indexed - private String lastName; - -} - - - - - The @Id annotation tells the mapper which - property you want to use for the MongoDB _id property and - the @Indexed annotation tells the mapping - framework to call ensureIndex on that property of your - document, making searches faster. - - - - Automatic index creation is only done for types annotated with - @Document. - - -
- Mapping annotation overview - - The MappingMongoConverter can use metadata to drive the mapping of - objects to documents. An overview of the annotations is provided - below - - - - @Id - applied at the field level to mark - the field used for identiy purpose. - - - - @Document - applied at the class level to - indicate this class is a candidate for mapping to the database. You - can specify the name of the collection where the database will be - stored. - - - - @DBRef - applied at the field to indicate - it is to be stored using a com.mongodb.DBRef. - - - - @Indexed - applied at the field level to - describe how to index the field. - - - - @CompoundIndex - applied at the type level - to declare Compound Indexes - - - - @GeoSpatialIndexed - applied at the field - level to describe how to geoindex the field. - - - - @TextIndexed - applied at the field level - to mark the field to be included in the text index. - - - - @Language - applied at the field level to - set the language override property for text index. - - - - @Transient - by default all private fields - are mapped to the document, this annotation excludes the field where - it is applied from being stored in the database - - - - @PersistenceConstructor - marks a given - constructor - even a package protected one - to use when - instantiating the object from the database. Constructor arguments - are mapped by name to the key values in the retrieved - DBObject. - - - - @Value - this annotation is part of the - Spring Framework . Within the mapping framework it can be applied to - constructor arguments. This lets you use a Spring Expression - Language statement to transform a key's value retrieved in the - database before it is used to construct a domain object. In order to - reference a property of a given document one has to use expressions - like: @Value("#root.myProperty") where - root refers to the root of the given - document. - - - - @Field - applied at the field level and - described the name of the field as it will be represented in the - MongoDB BSON document thus allowing the name to be different than - the fieldname of the class. - - - - The mapping metadata infrastructure is defined in a seperate - spring-data-commons project that is technology agnostic. Specific - subclasses are using in the MongoDB support to support annotation based - metadata. Other strategies are also possible to put in place if there is - demand. - - Here is an example of a more complex mapping. - - @Document -@CompoundIndexes({ - @CompoundIndex(name = "age_idx", def = "{'lastName': 1, 'age': -1}") -}) -public class Person<T extends Address> { - - @Id - private String id; - - @Indexed(unique = true) - private Integer ssn; - - @Field("fName") - private String firstName; - - @Indexed - private String lastName; - - private Integer age; - - @Transient - private Integer accountTotal; - - @DBRef - private List<Account> accounts; - - private T address; - - - public Person(Integer ssn) { - this.ssn = ssn; - } - - @PersistenceConstructor - public Person(Integer ssn, String firstName, String lastName, Integer age, T address) { - this.ssn = ssn; - this.firstName = firstName; - this.lastName = lastName; - this.age = age; - this.address = address; - } - - public String getId() { - return id; - } - - // no setter for Id. (getter is only exposed for some unit testing) - - public Integer getSsn() { - return ssn; - } - - -// other getters/setters ommitted - - - -
- -
- Customized Object Construction - - The mapping subsystem allows the customization of the object - construction by annotating a constructor with the - @PersistenceConstructor annotation. The values to be - used for the constructor parameters are resolved in the following - way: - - - - If a parameter is annotated with the @Value - annotation, the given expression is evaluated and the result is used - as the parameter value. - - - - If the Java type has a property whose name matches the given - field of the input document, then it's property information is used - to select the appropriate constructor parameter to pass the input - field value to. This works only if the parameter name information is - present in the java .class files which can be achieved by compiling - the source with debug information or using the new - -parameters command-line switch for javac in Java - 8. - - - - Otherwise an MappingException will be - thrown indicating that the given constructor parameter could not be - bound. - - - - class OrderItem { - - private @Id String id; - private int quantity; - private double unitPrice; - - OrderItem(String id, @Value("#root.qty ?: 0") int quantity, double unitPrice) { - this.id = id; - this.quantity = quantity; - this.unitPrice = unitPrice; - } - - // getters/setters ommitted -} - -DBObject input = new BasicDBObject("id", "4711"); -input.put("unitPrice", 2.5); -input.put("qty",5); -OrderItem item = converter.read(OrderItem.class, input); - - - The SpEL expression in the @Value annotation - of the quantity parameter falls back to the value - 0 if the given property path cannot be - resolved. - - - Additional examples for using the - @PersistenceConstructor annotation can be found - in the MappingMongoConverterUnitTests - test suite. -
- -
- Compound Indexes - - Compound indexes are also supported. They are defined at the class - level, rather than on indidvidual properties. - - - Compound indexes are very important to improve the performance - of queries that involve criteria on multiple fields - - - Here's an example that creates a compound index of - lastName in ascending order and age in - descending order: - Example Compound Index Usage - - package com.mycompany.domain; - -@Document -@CompoundIndexes({ - @CompoundIndex(name = "age_idx", def = "{'lastName': 1, 'age': -1}") -}) -public class Person { - - @Id - private ObjectId id; - private Integer age; - private String firstName; - private String lastName; - -} - - -
- -
- Text Indexes - - - The text index feature is disabled by default for mongodb - v.2.4. - - - Creating a text index allows to accumulate several fields into a - searchable full text index. It is only possible to have one text index - per collection so all fields marked with - @TextIndexed are combined into this - index. Properties can be weighted to influence document score for - ranking results. The default language for the text index is english, to - change the default language set - @Document(language="spanish") to any - language you want. Using a property called language - or @Language allows to define a language - override on a per document base. - - - Example Text Index Usage - - @Document(language = "spanish") -class SomeEntity { - - @TextIndexed String foo; - - @Language String lang; - - Nested nested; - - -} - -class Nested { - - @TextIndexed(weight=5) String bar; - - String roo; -} - - -
- -
- Using DBRefs - - The mapping framework doesn't have to store child objects embedded - within the document. You can also store them separately and use a DBRef - to refer to that document. When the object is loaded from MongoDB, those - references will be eagerly resolved and you will get back a mapped - object that looks the same as if it had been stored embedded within your - master document. - - Here's an example of using a DBRef to refer to a specific document - that exists independently of the object in which it is referenced (both - classes are shown in-line for brevity's sake): - - - -@Document -public class Account { - - @Id - private ObjectId id; - private Float total; - -} - -@Document -public class Person { - - @Id - private ObjectId id; - @Indexed - private Integer ssn; - @DBRef - private List<Account> accounts; - -} - - - - There's no need to use something like @OneToMany - because the mapping framework sees that you're wanting a one-to-many - relationship because there is a List of objects. When the object is - stored in MongoDB, there will be a list of DBRefs rather than the - Account objects themselves. - The mapping framework does not handle cascading saves. If you - change an Account object that is referenced by a - Person object, you must save the Account object - separately. Calling save on the Person - object will not automatically save the Account objects - in the property accounts. - -
- -
- Mapping Framework Events - - Events are fired throughout the lifecycle of the mapping process. - This is described in the Lifecycle Events - section. - - Simply declaring these beans in your Spring ApplicationContext - will cause them to be invoked whenever the event is dispatched. -
- -
- Overriding Mapping with explicit Converters - - When storing and querying your objects it is convenient to have a - MongoConverter instance handle the - mapping of all Java types to DBObjects. However, sometimes you may want - the MongoConverter's do most of the work - but allow you to selectivly handle the conversion for a particular type - or to optimize performance. - - To selectivly handle the conversion yourself, register one or more - one or more - org.springframework.core.convert.converter.Converter - instances with the MongoConverter. - - - Spring 3.0 introduced a core.convert package that provides a - general type conversion system. This is described in detail in the - Spring reference documentation section entitled Spring - 3 Type Conversion. - - - The method customConversions in - AbstractMongoConfiguration can be used to - configure Converters. The examples here at the begining of this - chapter show how to perform the configuration using Java and XML. - - Below is an example of a Spring Converter implementation that - converts from a DBObject to a Person POJO. - - @ReadingConverter - public class PersonReadConverter implements Converter<DBObject, Person> { - - public Person convert(DBObject source) { - Person p = new Person((ObjectId) source.get("_id"), (String) source.get("name")); - p.setAge((Integer) source.get("age")); - return p; - } - -} - - Here is an example that converts from a Person to a - DBObject. - - @WritingConverter -public class PersonWriteConverter implements Converter<Person, DBObject> { - - public DBObject convert(Person source) { - DBObject dbo = new BasicDBObject(); - dbo.put("_id", source.getId()); - dbo.put("name", source.getFirstName()); - dbo.put("age", source.getAge()); - return dbo; - } - -} -
-
- diff --git a/src/docbkx/reference/mongo-repositories.xml b/src/docbkx/reference/mongo-repositories.xml deleted file mode 100644 index df8a1a58a..000000000 --- a/src/docbkx/reference/mongo-repositories.xml +++ /dev/null @@ -1,652 +0,0 @@ - - - - MongoDB repositories - -
- Introduction - - This chapter will point out the specialties for repository support - for MongoDB. This builds on the core repository support explained in . So make sure you've got a sound understanding of - the basic concepts explained there. -
- -
- Usage - - To access domain entities stored in a MongoDB you can leverage our - sophisticated repository support that eases implementing those quite - significantly. To do so, simply create an interface for your - repository: - - - Sample Person entity - - public class Person { - - @Id - private String id; - private String firstname; - private String lastname; - private Address address; - - // … getters and setters omitted -} - - - - We have a quite simple domain object here. Note that it has a - property named id of typeObjectId. The - default serialization mechanism used in - MongoTemplate (which is backing the repository - support) regards properties named id as document id. Currently we - supportString, ObjectId and - BigInteger as id-types. - - - Basic repository interface to persist Person entities - - public interface PersonRepository extends PagingAndSortingRepository<Person, Long> { - - // additional custom finder methods go here -} - - - - Right now this interface simply serves typing purposes but we will - add additional methods to it later. In your Spring configuration simply - add - - - General MongoDB repository Spring configuration - - <?xml version="1.0" encoding="UTF-8"?> -<beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation="http://www.springframework.org/schema/beans - http://www.springframework.org/schema/beans/spring-beans-3.0.xsd - http://www.springframework.org/schema/data/mongo - http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd"> - - <mongo:mongo id="mongo" /> - - <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg ref="mongo" /> - <constructor-arg value="databaseName" /> - </bean> - - <mongo:repositories base-package="com.acme.*.repositories" /> - -</beans> - - - This namespace element will cause the base packages to be scanned - for interfaces extending MongoRepository - and create Spring beans for each of them found. By default the - repositories will get a MongoTemplate Spring bean - wired that is called mongoTemplate, so you only need to - configure mongo-template-ref explicitly if you deviate from - this convention. - - If you'd rather like to go with JavaConfig use the - @EnableMongoRepositories annotation. The - annotation carries the very same attributes like the namespace element. If - no base package is configured the infrastructure will scan the package of - the annotated configuration class. - - - JavaConfig for repositories - - @Configuration -@EnableMongoRepositories -class ApplicationConfig extends AbstractMongoConfiguration { - - @Override - protected String getDatabaseName() { - return "e-store"; - } - - @Override - public Mongo mongo() throws Exception { - return new Mongo(); - } - - @Override - protected String getMappingBasePackage() { - return "com.oreilly.springdata.mongodb" - } -} - - - As our domain repository extends - PagingAndSortingRepository it provides you - with CRUD operations as well as methods for paginated and sorted access to - the entities. Working with the repository instance is just a matter of - dependency injecting it into a client. So accessing the second page of - Persons at a page size of 10 would simply look - something like this: - - - Paging access to Person entities - - @RunWith(SpringJUnit4ClassRunner.class) -@ContextConfiguration -public class PersonRepositoryTests { - - @Autowired PersonRepository repository; - - @Test - public void readsFirstPageCorrectly() { - - Page<Person> persons = repository.findAll(new PageRequest(0, 10)); - assertThat(persons.isFirstPage(), is(true)); - } -} - - - The sample creates an application context with Spring's unit test - support which will perform annotation based dependency injection into test - cases. Inside the test method we simply use the repository to query the - datastore. We hand the repository a PageRequest - instance that requests the first page of persons at a page size of - 10. -
- -
- Query methods - - Most of the data access operations you usually trigger on a - repository result a query being executed against the MongoDB databases. - Defining such a query is just a matter of declaring a method on the - repository interface - - - PersonRepository with query methods - - public interface PersonRepository extends PagingAndSortingRepository<Person, String> { - - List<Person> findByLastname(String lastname); - - Page<Person> findByFirstname(String firstname, Pageable pageable); - - Person findByShippingAddresses(Address address); - -} - - - The first method shows a query for all people with the given - lastname. The query will be derived parsing the method name for - constraints which can be concatenated with And and - Or. Thus the method name will result in a query - expression of{"lastname" : lastname}. The second example - shows how pagination is applied to a query. Just equip your method - signature with a Pageable parameter and let - the method return a Page instance and we - will automatically page the query accordingly. The third examples shows - that you can query based on properties which are not a primitive - type. - - - Note that for version 1.0 we currently don't support referring to - parameters that are mapped as DBRef in the domain - class. - - - - Supported keywords for query methods - - - - - - - - - - - Keyword - - Sample - - Logical result - - - - - - GreaterThan - - findByAgeGreaterThan(int - age) - - {"age" : {"$gt" : age}} - - - - GreaterThanEqual - - findByAgeGreaterThanEqual(int - age) - - {"age" : {"$gte" : age}} - - - - LessThan - - findByAgeLessThan(int - age) - - {"age" : {"$lt" : age}} - - - - LessThanEqual - - findByAgeLessThanEqual(int - age) - - {"age" : {"$lte" : age}} - - - - Between - - findByAgeBetween(int from, int - to) - - {"age" : {"$gt" : from, "$lt" : to}} - - - - In - - findByAgeIn(Collection ages) - - - {"age" : {"$in" : [ages...]}} - - - - NotIn - - findByAgeNotIn(Collection ages) - - - {"age" : {"$nin" : [ages...]}} - - - - IsNotNull, - NotNull - - findByFirstnameNotNull() - - {"age" : {"$ne" : null}} - - - - IsNull, - Null - - findByFirstnameNull() - - {"age" : null} - - - - Like - - findByFirstnameLike(String - name) - - {"age" : age} ( age as - regex) - - - - Regex - - findByFirstnameRegex(String - firstname) - - {"firstname" : {"$regex" : firstname - }} - - - - (No keyword) - - findByFirstname(String - name) - - {"age" : name} - - - - Not - - findByFirstnameNot(String - name) - - {"age" : {"$ne" : name}} - - - - Near - - findByLocationNear(Point - point) - - {"location" : {"$near" : [x,y]}} - - - - Within - - findByLocationWithin(Circle - circle) - - {"location" : {"$within" : {"$center" : [ [x, y], - distance]}}} - - - - Within - - findByLocationWithin(Box - box) - - {"location" : {"$within" : {"$box" : [ [x1, y1], - x2, y2]}}}True - - - - IsTrue, - True - - findByActiveIsTrue() - - {"active" : true} - - - - IsFalse, - False - - findByActiveIsFalse() - - {"active" : false} - - - - Exists - - findByLocationExists(boolean - exists) - - {"location" : {"$exists" : exists }} - - - -
- -
- Repository delete queries - - The above keywords can be used in conjunciton with - delete…By or remove…By to create queries - deleting matching documents. - - - <code>Delete…By</code> Query - - public interface PersonRepository extends MongoRepository<Person, String> { - List <Person> deleteByLastname(String lastname); - - Long deletePersonByLastname(String lastname); -} - - - Using return type List will - retrieve and return all matching documents before actually deleting - them. A numeric return type directly removes the matching documents - returning the total number of documents removed. -
- -
- Geo-spatial repository queries - - As you've just seen there are a few keywords triggering - geo-spatial operations within a MongoDB query. The Near - keyword allows some further modification. Let's have look at some - examples: - - - Advanced <code>Near</code> queries - - public interface PersonRepository extends MongoRepository<Person, String> - - // { 'location' : { '$near' : [point.x, point.y], '$maxDistance' : distance}} - List<Person> findByLocationNear(Point location, Distance distance); -} - - - Adding a Distance parameter to the query - method allows restricting results to those within the given distance. If - the Distance was set up containing a - Metric we will transparently use - $nearSphere instead of $code. - - - Using <code>Distance</code> with <code>Metrics</code> - - Point point = new Point(43.7, 48.8); -Distance distance = new Distance(200, Metrics.KILOMETERS); -… = repository.findByLocationNear(point, distance); -// {'location' : {'$nearSphere' : [43.7, 48.8], '$maxDistance' : 0.03135711885774796}} - - - As you can see using a Distance equipped - with a Metric causes - $nearSphere clause to be added instead of a plain - $near. Beyond that the actual distance gets calculated - according to the Metrics used. - - - Geo-near queries - - - - public interface PersonRepository extends MongoRepository<Person, String> - - // {'geoNear' : 'location', 'near' : [x, y] } - GeoResults<Person> findByLocationNear(Point location); - - // No metric: {'geoNear' : 'person', 'near' : [x, y], maxDistance : distance } - // Metric: {'geoNear' : 'person', 'near' : [x, y], 'maxDistance' : distance, - // 'distanceMultiplier' : metric.multiplier, 'spherical' : true } - GeoResults<Person> findByLocationNear(Point location, Distance distance); - - // {'geoNear' : 'location', 'near' : [x, y] } - GeoResults<Person> findByLocationNear(Point location); -} - -
- -
- MongoDB JSON based query methods and field restriction - - By adding the annotation - org.springframework.data.mongodb.repository.Query - repository finder methods you can specify a MongoDB JSON query string to - use instead of having the query derived from the method name. For - example - - public interface PersonRepository extends MongoRepository<Person, String> - - @Query("{ 'firstname' : ?0 }") - List<Person> findByThePersonsFirstname(String firstname); - -} - - The placeholder ?0 lets you substitute the value from the method - arguments into the JSON query string. - - You can also use the filter property to restrict the set of - properties that will be mapped into the Java object. For example, - - public interface PersonRepository extends MongoRepository<Person, String> - - @Query(value="{ 'firstname' : ?0 }", fields="{ 'firstname' : 1, 'lastname' : 1}") - List<Person> findByThePersonsFirstname(String firstname); - -} - - This will return only the firstname, lastname and Id properties of - the Person objects. The age property, a java.lang.Integer, will not be - set and its value will therefore be null. -
- -
- Type-safe Query methods - - MongoDB repository support integrates with the QueryDSL project which provides a - means to perform type-safe queries in Java. To quote from the project - description, "Instead of writing queries as inline strings or - externalizing them into XML files they are constructed via a fluent - API." It provides the following features - - - - Code completion in IDE (all properties, methods and operations - can be expanded in your favorite Java IDE) - - - - Almost no syntactically invalid queries allowed (type-safe on - all levels) - - - - Domain types and properties can be referenced safely (no - Strings involved!) - - - - Adopts better to refactoring changes in domain types - - - - Incremental query definition is easier - - - - Please refer to the QueryDSL documentation which describes how to - bootstrap your environment for APT based code generation using - Maven or using - Ant. - - Using QueryDSL you will be able to write queries as shown - below - - QPerson person = new QPerson("person"); -List<Person> result = repository.findAll(person.address.zipCode.eq("C0123")); - -Page<Person> page = repository.findAll(person.lastname.contains("a"), - new PageRequest(0, 2, Direction.ASC, "lastname")); - - QPerson is a class that is generated (via - the Java annotation post processing tool) which is a - Predicate that allows you to write type safe - queries. Notice that there are no strings in the query other than the - value "C0123". - - You can use the generated Predicate class - via the interface - QueryDslPredicateExecutor which is shown - below - - public interface QueryDslPredicateExecutor<T> { - - T findOne(Predicate predicate); - - List<T> findAll(Predicate predicate); - - List<T> findAll(Predicate predicate, OrderSpecifier<?>... orders); - - Page<T> findAll(Predicate predicate, Pageable pageable); - - Long count(Predicate predicate); -} - - - To use this in your repository implementation, simply inherit from - it in addition to other repository interfaces. This is shown - below - - public interface PersonRepository extends MongoRepository<Person, String>, QueryDslPredicateExecutor<Person> { - - // additional finder methods go here - -} - - We think you will find this an extremely powerful tool for writing - MongoDB queries. -
-
- -
- Miscellaneous - - - -
- CDI Integration - - Instances of the repository interfaces are usually created by a - container, which Spring is the most natural choice when working with - Spring Data. As of version 1.3.0 Spring Data MongoDB ships with a custom - CDI extension that allows using the repository abstraction in CDI - environments. The extension is part of the JAR so all you need to do to - activate it is dropping the Spring Data MongoDB JAR into your classpath. - You can now set up the infrastructure by implementing a CDI Producer for - the MongoTemplate: - - class MongoTemplateProducer { - - @Produces - @ApplicationScoped - public MongoOperations createMongoTemplate() throws UnknownHostException, MongoException { - - MongoDbFactory factory = new SimpleMongoDbFactory(new Mongo(), "database"); - return new MongoTemplate(factory); - } -} - - The Spring Data MongoDB CDI extension will pick up the - MongoTemplate available as CDI bean and create a - proxy for a Spring Data repository whenever an bean of a repository type - is requested by the container. Thus obtaining an instance of a Spring - Data repository is a matter of declaring an @Inject-ed - property: - - class RepositoryClient { - - @Inject - PersonRepository repository; - - public void businessMethod() { - - List<Person> people = repository.findAll(); - } -} -
-
- diff --git a/src/docbkx/reference/mongodb.xml b/src/docbkx/reference/mongodb.xml deleted file mode 100644 index 66301bb8d..000000000 --- a/src/docbkx/reference/mongodb.xml +++ /dev/null @@ -1,3546 +0,0 @@ - - - - MongoDB support - - The MongoDB support contains a wide range of features which are - summarized below. - - - - Spring configuration support using Java based @Configuration - classes or an XML namespace for a Mongo driver instance and replica - sets - - - - MongoTemplate helper class that increases productivity performing - common Mongo operations. Includes integrated object mapping between - documents and POJOs. - - - - Exception translation into Spring's portable Data Access Exception - hierarchy - - - - Feature Rich Object Mapping integrated with Spring's Conversion - Service - - - - Annotation based mapping metadata but extensible to support other - metadata formats - - - - Persistence and mapping lifecycle events - - - - Java based Query, Criteria, and Update DSLs - - - - Automatic implementation of Repository interfaces including - support for custom finder methods. - - - - QueryDSL integration to support type-safe queries. - - - - Cross-store persistance - support for JPA Entities with fields - transparently persisted/retrieved using MongoDB - - - - Log4j log appender - - - - GeoSpatial integration - - - - For most tasks you will find yourself using - MongoTemplate or the Repository support that both - leverage the rich mapping functionality. MongoTemplate is the place to look - for accessing functionality such as incrementing counters or ad-hoc CRUD - operations. MongoTemplate also provides callback methods so that it is easy - for you to get a hold of the low level API artifacts such as - org.mongo.DB to communicate directly with MongoDB. The - goal with naming conventions on various API artifacts is to copy those in - the base MongoDB Java driver so you can easily map your existing knowledge - onto the Spring APIs. - -
- Getting Started - - Spring MongoDB support requires MongoDB 1.4 or higher and Java SE 5 - or higher. The latest production release (2.4.9 as of this writing) is - recommended. An easy way to bootstrap setting up a working environment is - to create a Spring based project in STS. - - First you need to set up a running Mongodb server. Refer to the - Mongodb - Quick Start guide for an explanation on how to startup a MongoDB - instance. Once installed starting MongoDB is typically a matter of - executing the following command: - MONGO_HOME/bin/mongod - - To create a Spring project in STS go to File -> New -> Spring - Template Project -> Simple Spring Utility Project -> press Yes when - prompted. Then enter a project and a package name such as - org.spring.mongodb.example. - - Then add the following to pom.xml dependencies section. - - <dependencies> - - <!-- other dependency elements omitted --> - - <dependency> - <groupId>org.springframework.data</groupId> - <artifactId>spring-data-mongodb</artifactId> - <version>1.4.1.RELEASE</version> - </dependency> - -</dependencies> - - Also change the version of Spring in the pom.xml to be - - <spring.framework.version>3.2.8.RELEASE</spring.framework.version> - - You will also need to add the location of the Spring Milestone - repository for maven to your pom.xml which is at the same level of your - <dependencies/> element - - <repositories> - <repository> - <id>spring-milestone</id> - <name>Spring Maven MILESTONE Repository</name> - <url>http://repo.spring.io/libs-milestone</url> - </repository> -</repositories> - - The repository is also browseable - here. - - You may also want to set the logging level to DEBUG to - see some additional information, edit the log4j.properties file to - have - - log4j.category.org.springframework.data.document.mongodb=DEBUG -log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %40.40c:%4L - %m%n - - Create a simple Person class to persist - - package org.spring.mongodb.example; - -public class Person { - - private String id; - private String name; - private int age; - - public Person(String name, int age) { - this.name = name; - this.age = age; - } - - public String getId() { - return id; - } - public String getName() { - return name; - } - public int getAge() { - return age; - } - - @Override - public String toString() { - return "Person [id=" + id + ", name=" + name + ", age=" + age + "]"; - } - -} - - And a main application to run - - package org.spring.mongodb.example; - -import static org.springframework.data.mongodb.core.query.Criteria.where; - -import org.apache.commons.logging.Log; -import org.apache.commons.logging.LogFactory; -import org.springframework.data.mongodb.core.MongoOperations; -import org.springframework.data.mongodb.core.MongoTemplate; -import org.springframework.data.mongodb.core.query.Query; - -import com.mongodb.Mongo; - -public class MongoApp { - - private static final Log log = LogFactory.getLog(MongoApp.class); - - public static void main(String[] args) throws Exception { - - MongoOperations mongoOps = new MongoTemplate(new Mongo(), "database"); - - mongoOps.insert(new Person("Joe", 34)); - - log.info(mongoOps.findOne(new Query(where("name").is("Joe")), Person.class)); - - mongoOps.dropCollection("person"); - } -} - - This will produce the following output - - 10:01:32,062 DEBUG apping.MongoPersistentEntityIndexCreator: 80 - Analyzing class class org.spring.example.Person for index information. -10:01:32,265 DEBUG ramework.data.mongodb.core.MongoTemplate: 631 - insert DBObject containing fields: [_class, age, name] in collection: Person -10:01:32,765 DEBUG ramework.data.mongodb.core.MongoTemplate:1243 - findOne using query: { "name" : "Joe"} in db.collection: database.Person -10:01:32,953 INFO org.spring.mongodb.example.MongoApp: 25 - Person [id=4ddbba3c0be56b7e1b210166, name=Joe, age=34] -10:01:32,984 DEBUG ramework.data.mongodb.core.MongoTemplate: 375 - Dropped collection [database.person] - - Even in this simple example, there are few things to take notice - of - - - - You can instantiate the central helper class of Spring Mongo, - MongoTemplate, - using the standard com.mongodb.Mongo object and - the name of the database to use. - - - - The mapper works against standard POJO objects without the need - for any additional metadata (though you can optionally provide that - information. See here.). - - - - Conventions are used for handling the id field, converting it to - be a ObjectId when stored in the database. - - - - Mapping conventions can use field access. Notice the Person - class has only getters. - - - - If the constructor argument names match the field names of the - stored document, they will be used to instantiate the object - - -
- -
- Examples Repository - - There is an github - repository with several examples that you can download and play - around with to get a feel for how the library works. -
- -
- Connecting to MongoDB with Spring - - One of the first tasks when using MongoDB and Spring is to create a - com.mongodb.Mongo object using the IoC container. - There are two main ways to do this, either using Java based bean metadata - or XML based bean metadata. These are discussed in the following sections. - - For those not familiar with how to configure the Spring - container using Java based bean metadata instead of XML based metadata - see the high level introduction in the reference docs here as well as the detailed documentation - here. - - -
- Registering a Mongo instance using Java based metadata - - An example of using Java based bean metadata to register an - instance of a com.mongodb.Mongo is shown below - - Registering a com.mongodb.Mongo object using Java based bean - metadata - - @Configuration -public class AppConfig { - - /* - * Use the standard Mongo driver API to create a com.mongodb.Mongo instance. - */ - public @Bean Mongo mongo() throws UnknownHostException { - return new Mongo("localhost"); - } -} - - - This approach allows you to use the standard - com.mongodb.Mongo API that you may already be - used to using but also pollutes the code with the UnknownHostException - checked exception. The use of the checked exception is not desirable as - Java based bean metadata uses methods as a means to set object - dependencies, making the calling code cluttered. - - An alternative is to register an instance of - com.mongodb.Mongo instance with the container - using Spring's MongoFactoryBean. As - compared to instantiating a com.mongodb.Mongo - instance directly, the FactoryBean approach does not throw a checked - exception and has the added advantage of also providing the container - with an ExceptionTranslator implementation that translates MongoDB - exceptions to exceptions in Spring's portable - DataAccessException hierarchy for data access - classes annoated with the @Repository annotation. - This hierarchy and use of @Repository is described in - Spring's - DAO support features. - - An example of a Java based bean metadata that supports exception - translation on @Repository annotated classes is - shown below: - - - Registering a com.mongodb.Mongo object using Spring's - MongoFactoryBean and enabling Spring's exception translation - support - - @Configuration -public class AppConfig { - - /* - * Factory bean that creates the com.mongodb.Mongo instance - */ - public @Bean MongoFactoryBean mongo() { - MongoFactoryBean mongo = new MongoFactoryBean(); - mongo.setHost("localhost"); - return mongo; - } -} - - - To access the com.mongodb.Mongo object - created by the MongoFactoryBean in other - @Configuration or your own classes, use a - "private @Autowired Mongo mongo;" field. - -
- -
- Registering a Mongo instance using XML based metadata - - While you can use Spring's traditional - <beans/> XML namespace to register an instance - of com.mongodb.Mongo with the container, the XML - can be quite verbose as it is general purpose. XML namespaces are a - better alternative to configuring commonly used objects such as the - Mongo instance. The mongo namespace alows you to create a Mongo instance - server location, replica-sets, and options. - - To use the Mongo namespace elements you will need to reference the - Mongo schema: - - - XML schema to configure MongoDB - - <?xml version="1.0" encoding="UTF-8"?> -<beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:context="http://www.springframework.org/schema/context" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation= - "http://www.springframework.org/schema/context - http://www.springframework.org/schema/context/spring-context-3.0.xsd - http://www.springframework.org/schema/data/mongo - http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd - http://www.springframework.org/schema/beans - http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> - - <!-- Default bean name is 'mongo' --> - <mongo:mongo host="localhost" port="27017"/> - -</beans> - - - - A more advanced configuration with MongoOptions is shown below - (note these are not recommended values) - - - XML schema to configure a com.mongodb.Mongo object with - MongoOptions - - <beans> - - <mongo:mongo host="localhost" port="27017"> - <mongo:options connections-per-host="8" - threads-allowed-to-block-for-connection-multiplier="4" - connect-timeout="1000" - max-wait-time="1500}" - auto-connect-retry="true" - socket-keep-alive="true" - socket-timeout="1500" - slave-ok="true" - write-number="1" - write-timeout="0" - write-fsync="true"/> - </mongo:mongo/> - -</beans> - - - - A configuration using replica sets is shown below. - XML schema to configure com.mongodb.Mongo object with Replica - Sets - - <mongo:mongo id="replicaSetMongo" replica-set="127.0.0.1:27017,localhost:27018"/> - -
- -
- The MongoDbFactory interface - - While com.mongodb.Mongo is the entry point - to the MongoDB driver API, connecting to a specific MongoDB database - instance requires additional information such as the database name and - an optional username and password. With that information you can obtain - a com.mongodb.DB object and access all the functionality of a specific - MongoDB database instance. Spring provides the - org.springframework.data.mongodb.core.MongoDbFactory - interface shown below to bootstrap connectivity to the database. - - public interface MongoDbFactory { - - DB getDb() throws DataAccessException; - - DB getDb(String dbName) throws DataAccessException; -} - - The following sections show how you can use the container with - either Java or the XML based metadata to configure an instance of the - MongoDbFactory interface. In turn, you can use - the MongoDbFactory instance to configure - MongoTemplate. - - The class - org.springframework.data.mongodb.core.SimpleMongoDbFactory - provides implements the MongoDbFactory interface and is created with a - standard com.mongodb.Mongo instance, the database - name and an optional - org.springframework.data.authentication.UserCredentials - constructor argument. - - Instead of using the IoC container to create an instance of - MongoTemplate, you can just use them in standard Java code as shown - below. - - public class MongoApp { - - private static final Log log = LogFactory.getLog(MongoApp.class); - - public static void main(String[] args) throws Exception { - - MongoOperations mongoOps = new MongoTemplate(new SimpleMongoDbFactory(new Mongo(), "database")); - - mongoOps.insert(new Person("Joe", 34)); - - log.info(mongoOps.findOne(new Query(where("name").is("Joe")), Person.class)); - - mongoOps.dropCollection("person"); - } -} - - The code in bold highlights the use of SimpleMongoDbFactory and is - the only difference between the listing shown in the getting started - section. -
- -
- Registering a MongoDbFactory instance using Java based - metadata - - To register a MongoDbFactory instance with the container, you - write code much like what was highlighted in the previous code listing. - A simple example is shown below - - @Configuration -public class MongoConfiguration { - - public @Bean MongoDbFactory mongoDbFactory() throws Exception { - return new SimpleMongoDbFactory(new Mongo(), "database"); - } -} - - To define the username and password create an instance of - org.springframework.data.authentication.UserCredentials - and pass it into the constructor as shown below. This listing also shows - using MongoDbFactory register an instance of - MongoTemplate with the container. - - @Configuration -public class MongoConfiguration { - - public @Bean MongoDbFactory mongoDbFactory() throws Exception { - UserCredentials userCredentials = new UserCredentials("joe", "secret"); - return new SimpleMongoDbFactory(new Mongo(), "database", userCredentials); - } - - public @Bean MongoTemplate mongoTemplate() throws Exception { - return new MongoTemplate(mongoDbFactory()); - } -} -
- -
- Registering a MongoDbFactory instance using XML based - metadata - - The mongo namespace provides a convient way to create a - SimpleMongoDbFactory as compared to using - the<beans/> namespace. Simple usage is shown - below - - <mongo:db-factory dbname="database"> - - In the above example a com.mongodb.Mongo - instance is created using the default host and port number. The - SimpleMongoDbFactory registered with the - container is identified by the id 'mongoDbFactory' unless a value for - the id attribute is specified. - - You can also provide the host and port for the underlying - com.mongodb.Mongo instance as shown below, in - addition to username and password for the database. - - <mongo:db-factory id="anotherMongoDbFactory" - host="localhost" - port="27017" - dbname="database" - username="joe" - password="secret"/> - - If you need to configure additional options on the - com.mongodb.Mongo instance that is used to create - a SimpleMongoDbFactory you can refer to an - existing bean using the mongo-ref attribute as shown - below. To show another common usage pattern, this listing show the use - of a property placeholder to parameterise the configuration and creating - MongoTemplate. - - <context:property-placeholder location="classpath:/com/myapp/mongodb/config/mongo.properties"/> - -<mongo:mongo host="${mongo.host}" port="${mongo.port}"> - <mongo:options - connections-per-host="${mongo.connectionsPerHost}" - threads-allowed-to-block-for-connection-multiplier="${mongo.threadsAllowedToBlockForConnectionMultiplier}" - connect-timeout="${mongo.connectTimeout}" - max-wait-time="${mongo.maxWaitTime}" - auto-connect-retry="${mongo.autoConnectRetry}" - socket-keep-alive="${mongo.socketKeepAlive}" - socket-timeout="${mongo.socketTimeout}" - slave-ok="${mongo.slaveOk}" - write-number="1" - write-timeout="0" - write-fsync="true"/> -</mongo:mongo> - -<mongo:db-factory dbname="database" mongo-ref="mongo"/> - -<bean id="anotherMongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg name="mongoDbFactory" ref="mongoDbFactory"/> -</bean> -
-
- -
- General auditing configuration - - Activating auditing functionality is just a matter of adding the - Spring Data Mongo auditing namespace element to your - configuration: - - - Activating auditing using XML configuration - - <mongo:auditing mapping-context-ref="customMappingContext" auditor-aware-ref="yourAuditorAwareImpl"/> - - - Since Spring Data MongoDB 1.4 auditing can be enabled by annotating - a configuration class with the @EnableMongoAuditing - annotation. - - - Activating auditing using JavaConfig - - @Configuration -@EnableMongoAuditing -class Config { - - @Bean - public AuditorAware<AuditableUser> myAuditorProvider() { - return new AuditorAwareImpl(); - } -} - - - If you expose a bean of type - AuditorAware to the - ApplicationContext, the auditing - infrastructure will pick it up automatically and use it to determine the - current user to be set on domain types. If you have multiple - implementations registered in the - ApplicationContext, you can select the one - to be used by explicitly setting the auditorAwareRef - attribute of @EnableJpaAuditing. -
- -
- Introduction to MongoTemplate - - The class MongoTemplate, located in the - package org.springframework.data.document.mongodb, is - the central class of the Spring's MongoDB support providng a rich feature - set to interact with the database. The template offers convenience - operations to create, update, delete and query for MongoDB documents and - provides a mapping between your domain objects and MongoDB - documents. - - - Once configured, MongoTemplate is - thread-safe and can be reused across multiple instances. - - - The mapping between MongoDB documents and domain classes is done by - delegating to an implementation of the interface - MongoConverter. Spring provides two - implementations, SimpleMappingConverter and - MongoMappingConverter, but you can also write your - own converter. Please refer to the section on MongoCoverters for more - detailed information. - - The MongoTemplate class implements the - interface MongoOperations. In as much as - possible, the methods on MongoOperations - are named after methods available on the MongoDB driver - Collection object as as to make the API familiar to - existing MongoDB developers who are used to the driver API. For example, - you will find methods such as "find", "findAndModify", "findOne", - "insert", "remove", "save", "update" and "updateMulti". The design goal - was to make it as easy as possible to transition between the use of the - base MongoDB driver and MongoOperations. A - major difference in between the two APIs is that MongOperations can be - passed domain objects instead of DBObject and there - are fluent APIs for Query, - Criteria, and Update - operations instead of populating a DBObject to - specify the parameters for those operatiosn. - - - The preferred way to reference the operations on - MongoTemplate instance is via its interface - MongoOperations. - - - The default converter implementation used by - MongoTemplate is MongoMappingConverter. While the - MongoMappingConverter can make use of additional - metadata to specify the mapping of objects to documents it is also capable - of converting objects that contain no additonal metadata by using some - conventions for the mapping of IDs and collection names. These conventions - as well as the use of mapping annotations is explained in the Mapping chapter. - In the M2 release SimpleMappingConverter, - was the default and this class is now deprecated as its functionality - has been subsumed by the MongoMappingConverter. - - - Another central feature of MongoTemplate is exception translation of - exceptions thrown in the MongoDB Java driver into Spring's portable Data - Access Exception hierarchy. Refer to the section on exception translation for more - information. - - While there are many convenience methods on - MongoTemplate to help you easily perform common - tasks if you should need to access the MongoDB driver API directly to - access functionality not explicitly exposed by the MongoTemplate you can - use one of several Execute callback methods to access underlying driver - APIs. The execute callbacks will give you a reference to either a - com.mongodb.Collection or a - com.mongodb.DB object. Please see the section - Execution Callbacks for more - information. - - Now let's look at a examples of how to work with the - MongoTemplate in the context of the Spring - container. - -
- Instantiating MongoTemplate - - You can use Java to create and register an instance of - MongoTemplate as shown below. - - - Registering a com.mongodb.Mongo object and enabling Spring's - exception translation support - - @Configuration -public class AppConfig { - - public @Bean Mongo mongo() throws Exception { - return new Mongo("localhost"); - } - - public @Bean MongoTemplate mongoTemplate() throws Exception { - return new MongoTemplate(mongo(), "mydatabase"); - } -} - - - - There are several overloaded constructors of MongoTemplate. These - are - - - - MongoTemplate - (Mongo mongo, String databaseName) - takes the - com.mongodb.Mongo object and the default - database name to operate against. - - - - MongoTemplate - (Mongo mongo, String databaseName, UserCredentials - userCredentials) - adds the username and password for - authenticating with the database. - - - - MongoTemplate - (MongoDbFactory mongoDbFactory) - takes a - MongoDbFactory object that encapsulated the - com.mongodb.Mongo object, database name, and - username and password. - - - - MongoTemplate - (MongoDbFactory mongoDbFactory, MongoConverter - mongoConverter) - adds a MongoConverter to use for - mapping. - - - - You can also configure a MongoTemplate using Spring's XML - <beans/> schema. - - <mongo:mongo host="localhost" port="27017"/> - - <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg ref="mongo"/> - <constructor-arg name="databaseName" value="geospatial"/> - </bean> - - Other optional properties that you might like to set when creating - a MongoTemplate are the default - WriteResultCheckingPolicy, - WriteConcern, and - ReadPreference. - - - The preferred way to reference the operations on - MongoTemplate instance is via its interface - MongoOperations. - - -
- WriteResultChecking Policy - - When in development it is very handy to either log or throw an - exception if the com.mongodb.WriteResult - returned from any MongoDB operation contains an error. It is quite - common to forget to do this during development and then end up with an - application that looks like it runs successfully but in fact the - database was not modified according to your expectations. Set - MongoTemplate's WriteResultChecking property to - an enum with the following values, LOG, EXCEPTION, or NONE to either - log the error, throw and exception or do nothing. The default is to - use a WriteResultChecking value of NONE. -
- -
- WriteConcern - - You can set the com.mongodb.WriteConcern - property that the MongoTemplate will use for - write operations if it has not yet been specified via the driver at a - higher level such as com.mongodb.Mongo. If - MongoTemplate's WriteConcern property is not - set it will default to the one set in the MongoDB driver's DB or - Collection setting. -
- -
- WriteConcernResolver - - For more advanced cases where you want to set different - WriteConcern values on a per-operation basis - (for remove, update, insert and save operations), a strategy interface - called WriteConcernResolver can be - configured on MongoTemplate. Since - MongoTemplate is used to persist POJOs, the - WriteConcernResolver lets you create a - policy that can map a specific POJO class to a - WriteConcern value. The - WriteConcernResolver interface is shown - below. - - public interface WriteConcernResolver { - WriteConcern resolve(MongoAction action); -} - - The passed in argument, MongoAction, is what you use to - determine the WriteConcern value to be used or - to use the value of the Template itself as a default. - MongoAction contains the collection name being - written to, the java.lang.Class of the POJO, - the converted DBObject, as well as the - operation as an enumeration - (MongoActionOperation: REMOVE, UPDATE, INSERT, - INSERT_LIST, SAVE) and a few other pieces of contextual information. - For example, - - private class MyAppWriteConcernResolver implements WriteConcernResolver { - - public WriteConcern resolve(MongoAction action) { - if (action.getEntityClass().getSimpleName().contains("Audit")) { - return WriteConcern.NONE; - } else if (action.getEntityClass().getSimpleName().contains("Metadata")) { - return WriteConcern.JOURNAL_SAFE; - } - return action.getDefaultWriteConcern(); - } -} -
-
-
- -
- Saving, Updating, and Removing Documents - - MongoTemplate provides a simple way for you - to save, update, and delete your domain objects and map those objects to - documents stored in MongoDB. - - Given a simple class such as Person - - public class Person { - - private String id; - private String name; - private int age; - - public Person(String name, int age) { - this.name = name; - this.age = age; - } - - public String getId() { - return id; - } - public String getName() { - return name; - } - public int getAge() { - return age; - } - - @Override - public String toString() { - return "Person [id=" + id + ", name=" + name + ", age=" + age + "]"; - } - -} - - - You can save, update and delete the object as shown below. - - - MongoOperations is the interface - that MongoTemplate implements. - - - package org.spring.example; - -import static org.springframework.data.mongodb.core.query.Criteria.where; -import static org.springframework.data.mongodb.core.query.Update.update; -import static org.springframework.data.mongodb.core.query.Query.query; - -import java.util.List; - -import org.apache.commons.logging.Log; -import org.apache.commons.logging.LogFactory; -import org.springframework.data.mongodb.core.MongoOperations; -import org.springframework.data.mongodb.core.MongoTemplate; -import org.springframework.data.mongodb.core.SimpleMongoDbFactory; - -import com.mongodb.Mongo; - -public class MongoApp { - - private static final Log log = LogFactory.getLog(MongoApp.class); - - public static void main(String[] args) throws Exception { - - MongoOperations mongoOps = new MongoTemplate(new SimpleMongoDbFactory(new Mongo(), "database")); - - Person p = new Person("Joe", 34); - - // Insert is used to initially store the object into the database. - mongoOps.insert(p); - log.info("Insert: " + p); - - // Find - p = mongoOps.findById(p.getId(), Person.class); - log.info("Found: " + p); - - // Update - mongoOps.updateFirst(query(where("name").is("Joe")), update("age", 35), Person.class); - p = mongoOps.findOne(query(where("name").is("Joe")), Person.class); - log.info("Updated: " + p); - - // Delete - mongoOps.remove(p); - - // Check that deletion worked - List<Person> people = mongoOps.findAll(Person.class); - log.info("Number of people = : " + people.size()); - - - mongoOps.dropCollection(Person.class); - } -} - - - This would produce the following log output (including debug - messages from MongoTemplate itself) - - DEBUG apping.MongoPersistentEntityIndexCreator: 80 - Analyzing class class org.spring.example.Person for index information. -DEBUG work.data.mongodb.core.MongoTemplate: 632 - insert DBObject containing fields: [_class, age, name] in collection: person -INFO org.spring.example.MongoApp: 30 - Insert: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=34] -DEBUG work.data.mongodb.core.MongoTemplate:1246 - findOne using query: { "_id" : { "$oid" : "4ddc6e784ce5b1eba3ceaf5c"}} in db.collection: database.person -INFO org.spring.example.MongoApp: 34 - Found: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=34] -DEBUG work.data.mongodb.core.MongoTemplate: 778 - calling update using query: { "name" : "Joe"} and update: { "$set" : { "age" : 35}} in collection: person -DEBUG work.data.mongodb.core.MongoTemplate:1246 - findOne using query: { "name" : "Joe"} in db.collection: database.person -INFO org.spring.example.MongoApp: 39 - Updated: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=35] -DEBUG work.data.mongodb.core.MongoTemplate: 823 - remove using query: { "id" : "4ddc6e784ce5b1eba3ceaf5c"} in collection: person -INFO org.spring.example.MongoApp: 46 - Number of people = : 0 -DEBUG work.data.mongodb.core.MongoTemplate: 376 - Dropped collection [database.person] - - There was implicit conversion using the - MongoConverter between a - String and ObjectId as - stored in the database and recognizing a convention of the property "Id" - name. - - - This example is meant to show the use of save, update and remove - operations on MongoTemplate and not to show complex mapping - functionality - - - The query syntax used in the example is explained in more detail in - the section Querying Documents. - -
- How the '_id' field is handled in the mapping layer - - MongoDB requires that you have an '_id' field for all documents. - If you don't provide one the driver will assign a - ObjectId with a generated value. When using the - MongoMappingConverter there are certain rules - that govern how properties from the Java class is mapped to this '_id' - field. - - The following outlines what property will be mapped to the '_id' - document field: - - - - A property or field annotated with - @Id - (org.springframework.data.annotation.Id) - will be mapped to the '_id' field. - - - - A property or field without an annotation but named - id will be mapped to the '_id' - field. - - - - The following outlines what type conversion, if any, will be done - on the property mapped to the _id document field when using the - MappingMongoConverter, the default for - MongoTemplate. - - - - An id property or field declared as a String in the Java class - will be converted to and stored as an - ObjectId if possible using a Spring - Converter<String, ObjectId>. - Valid conversion rules are delegated to the MongoDB Java driver. If - it cannot be converted to an ObjectId, then the value will be stored - as a string in the database. - - - - An id property or field declared as - BigInteger in the Java class will be - converted to and stored as an ObjectId using - a Spring Converter<BigInteger, - ObjectId>. - - - - If no field or property specified above is present in the Java - class then an implicit '_id' file will be generated by the driver but - not mapped to a property or field of the Java class. - - When querying and updating MongoTemplate - will use the converter to handle conversions of the - Query and Update objects - that correspond to the above rules for saving documents so field names - and types used in your queries will be able to match what is in your - domain classes. -
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- Type mapping - - As MongoDB collections can contain documents that represent - instances of a variety of types. A great example here is if you store a - hierarchy of classes or simply have a class with a property of type - Object. In the latter case the values held inside - that property have to be read in correctly when retrieving the object. - Thus we need a mechanism to store type information alongside the actual - document. - - To achieve that the MappingMongoConverter - uses a MongoTypeMapper abstraction with - DefaultMongoTypeMapper as it's main - implementation. It's default behaviour is storing the fully qualified - classname under _class inside the document for the - top-level document as well as for every value if it's a complex type and - a subtype of the property type declared. - - - Type mapping - - public class Sample { - Contact value; -} - -public abstract class Contact { … } - -public class Person extends Contact { … } - -Sample sample = new Sample(); -sample.value = new Person(); - -mongoTemplate.save(sample); - -{ "_class" : "com.acme.Sample", - "value" : { "_class" : "com.acme.Person" } -} - - - As you can see we store the type information for the actual root - class persistent as well as for the nested type as it is complex and a - subtype of Contact. So if you're now using - mongoTemplate.findAll(Object.class, "sample") - we are able to find out that the document stored shall be a - Sample instance. We are also able to find out - that the value property shall be a Person - actually. - - - Customizing type mapping - - In case you want to avoid writing the entire Java class name as - type information but rather like to use some key you can use the - @TypeAlias annotation at the entity - class being persisted. If you need to customize the mapping even more - have a look at the - TypeInformationMapper interface. An - instance of that interface can be configured at the - DefaultMongoTypeMapper which can be configured - in turn on MappingMongoConverter. - - - Defining a TypeAlias for an Entity - - @TypeAlias("pers") -class Person { - -} - - Note that the resulting document will contain - "pers" as the value in the _class - Field. - - - - - Configuring custom type mapping - - The following example demonstrates how to configure a custom - MongoTypeMapper in - MappingMongoConverter. - - - Configuring a custom MongoTypeMapper via Spring Java - Config - - class CustomMongoTypeMapper extends DefaultMongoTypeMapper { - //implement custom type mapping here -} - - @Configuration -class SampleMongoConfiguration extends AbstractMongoConfiguration { - - @Override - protected String getDatabaseName() { - return "database"; - } - - @Override - public Mongo mongo() throws Exception { - return new Mongo(); - } - - @Bean - @Override - public MappingMongoConverter mappingMongoConverter() throws Exception { - MappingMongoConverter mmc = super.mappingMongoConverter(); - mmc.setTypeMapper(customTypeMapper()); - return mmc; - } - - @Bean - public MongoTypeMapper customTypeMapper() { - return new CustomMongoTypeMapper(); - } -} - - Note that we are extending the - AbstractMongoConfiguration class and override - the bean definition of the - MappingMongoConverter where we configure our - custom MongoTypeMapper. - - - - Configuring a custom MongoTypeMapper via XML - - <mongo:mapping-converter type-mapper-ref="customMongoTypeMapper"/> - -<bean name="customMongoTypeMapper" class="com.bubu.mongo.CustomMongoTypeMapper"/> - - -
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- Methods for saving and inserting documents - - There are several convenient methods on - MongoTemplate for saving and inserting your - objects. To have more fine grained control over the conversion process - you can register Spring converters with the - MappingMongoConverter, for example - Converter<Person, DBObject> and - Converter<DBObject, Person>. - - - The difference between insert and save operations is that a save - operation will perform an insert if the object is not already - present. - - - The simple case of using the save operation is to save a POJO. In - this case the collection name will be determined by name (not fully - qualfied) of the class. You may also call the save operation with a - specific collection name. The collection to store the object can be - overriden using mapping metadata. - - When inserting or saving, if the Id property is not set, the - assumption is that its value will be auto-generated by the database. As - such, for auto-generation of an ObjectId to succeed the type of the Id - property/field in your class must be either a - String, ObjectId, or - BigInteger. - - Here is a basic example of using the save operation and retrieving - its contents. - - - Inserting and retrieving documents using the - MongoTemplate - - import static org.springframework.data.mongodb.core.query.Criteria.where; -import static org.springframework.data.mongodb.core.query.Criteria.query; - -… - -Person p = new Person("Bob", 33); -mongoTemplate.insert(p); - -Person qp = mongoTemplate.findOne(query(where("age").is(33)), Person.class); - - - The insert/save operations available to you are listed - below. - - - - void save - (Object objectToSave) Save the - object to the default collection. - - - - void save - (Object objectToSave, String collectionName) - Save the object to the specified collection. - - - - A similar set of insert operations is listed below - - - - void insert (Object objectToSave) - Insert the object to the default collection. - - - - void insert - (Object objectToSave, String collectionName) - Insert the object to the specified collection. - - - -
- Which collection will my documents be saved into? - - There are two ways to manage the collection name that is used - for operating on the documents. The default collection name that is - used is the class name changed to start with a lower-case letter. So a - com.test.Person class would be stored in the - "person" collection. You can customize this by providing a different - collection name using the @Document annotation. You can also override - the collection name by providing your own collection name as the last - parameter for the selected MongoTemplate method calls. -
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- Inserting or saving individual objects - - The MongoDB driver supports inserting a collection of documents - in one operation. The methods in the MongoOperations interface that - support this functionality are listed below - - - - insert - Insert an object. If there is an existing document - with the same id then an error is generated. - - - - insertAll Takes a - Collection of objects as the first parameter. - This method inspects each object and inserts it to the - appropriate collection based on the rules specified - above. - - - - save Save the object - overwriting any object that might exist with the same id. - - -
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- Inserting several objects in a batch - - The MongoDB driver supports inserting a collection of documents - in one operation. The methods in the MongoOperations interface that - support this functionality are listed below - - - - insert methods - that take a Collection as the first - argument.This inserts a list of objects in a single - batch write to the database. - - -
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- Updating documents in a collection - - For updates we can elect to update the first document found using - MongoOperation's method - updateFirst or we can update all documents that were - found to match the query using the method - updateMulti. Here is an example of an update of all - SAVINGS accounts where we are adding a one time $50.00 bonus to the - balance using the $inc operator. - - - Updating documents using the MongoTemplate - - import static org.springframework.data.mongodb.core.query.Criteria.where; -import static org.springframework.data.mongodb.core.query.Query; -import static org.springframework.data.mongodb.core.query.Update; - - ... - - WriteResult wr = mongoTemplate.updateMulti(new Query(where("accounts.accountType").is(Account.Type.SAVINGS)), - new Update().inc("accounts.$.balance", 50.00), - Account.class); - - - - In addition to the Query discussed above we - provide the update definition using an Update - object. The Update class has methods that match - the update modifiers available for MongoDB. - - As you can see most methods return the - Update object to provide a fluent style for the - API. - -
- Methods for executing updates for documents - - - - updateFirst Updates the - first document that matches the query document criteria with the - provided updated document. - - - - updateMulti Updates all - objects that match the query document criteria with the provided - updated document. - - -
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- Methods for the Update class - - The Update class can be used with a little 'syntax sugar' as its - methods are meant to be chained together and you can kick-start the - creation of a new Update instance via the static method - public static Update update(String key, Object - value) and using static imports. - - Here is a listing of methods on the Update class - - - - Update addToSet - (String key, Object value) - Update using the $addToSet update - modifier - - - - Update inc - (String key, Number inc) Update - using the $inc update modifier - - - - Update pop - (String key, Update.Position pos) - Update using the $pop update - modifier - - - - Update pull - (String key, Object value) - Update using the $pull update modifier - - - - Update pullAll - (String key, Object[] values) - Update using the $pullAll update - modifier - - - - Update push - (String key, Object value) - Update using the $push update modifier - - - - Update pushAll - (String key, Object[] values) - Update using the $pushAll update - modifier - - - - Update rename - (String oldName, String newName) - Update using the $rename update - modifier - - - - Update set - (String key, Object value) - Update using the $set update modifier - - - - Update unset - (String key) Update using the - $unset update modifier - - -
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- Upserting documents in a collection - - Related to performing an updateFirst - operations, you can also perform an upsert operation which will perform - an insert if no document is found that matches the query. The document - that is inserted is a combination of the query document and the update - document. Here is an example - - template.upsert(query(where("ssn").is(1111).and("firstName").is("Joe").and("Fraizer").is("Update")), update("address", addr), Person.class); -
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- Finding and Upserting documents in a collection - - The findAndModify(…) method on - DBCollection can update a document and return either the old or newly - updated document in a single operation. - MongoTemplate provides a findAndModify method - that takes Query and - Update classes and converts from - DBObject to your POJOs. Here are the - methods - - <T> T findAndModify(Query query, Update update, Class<T> entityClass); - -<T> T findAndModify(Query query, Update update, Class<T> entityClass, String collectionName); - -<T> T findAndModify(Query query, Update update, FindAndModifyOptions options, Class<T> entityClass); - -<T> T findAndModify(Query query, Update update, FindAndModifyOptions options, Class<T> entityClass, String collectionName); - - As an example usage, we will insert of few - Person objects into the container and perform a - simple findAndUpdate operation - - mongoTemplate.insert(new Person("Tom", 21)); -mongoTemplate.insert(new Person("Dick", 22)); -mongoTemplate.insert(new Person("Harry", 23)); - -Query query = new Query(Criteria.where("firstName").is("Harry")); -Update update = new Update().inc("age", 1); -Person p = mongoTemplate.findAndModify(query, update, Person.class); // return's old person object - -assertThat(p.getFirstName(), is("Harry")); -assertThat(p.getAge(), is(23)); -p = mongoTemplate.findOne(query, Person.class); -assertThat(p.getAge(), is(24)); - - -// Now return the newly updated document when updating -p = template.findAndModify(query, update, new FindAndModifyOptions().returnNew(true), Person.class); -assertThat(p.getAge(), is(25)); - - The FindAndModifyOptions lets you set the - options of returnNew, upsert, and remove. An example extending off the - previous code snippit is shown below - - Query query2 = new Query(Criteria.where("firstName").is("Mary")); -p = mongoTemplate.findAndModify(query2, update, new FindAndModifyOptions().returnNew(true).upsert(true), Person.class); -assertThat(p.getFirstName(), is("Mary")); -assertThat(p.getAge(), is(1)); -
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- Methods for removing documents - - You can use several overloaded methods to remove an object from - the database. - - - - remove Remove the given - document based on one of the following: a specific object - instance, a query document criteria combined with a class or a - query document criteria combined with a specific collection - name. - - -
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- Querying Documents - - You can express your queries using the Query - and Criteria classes which have method names that - mirror the native MongoDB operator names such as lt, - lte, is, and others. The - Query and Criteria classes - follow a fluent API style so that you can easily chain together multiple - method criteria and queries while having easy to understand code. Static - imports in Java are used to help remove the need to see the 'new' keyword - for creating Query and - Criteria instances so as to improve readability. If - you like to create Query instances from a plain - JSON String use BasicQuery. - - - Creating a Query instance from a plain JSON String - - BasicQuery query = new BasicQuery("{ age : { $lt : 50 }, accounts.balance : { $gt : 1000.00 }}"); -List<Person> result = mongoTemplate.find(query, Person.class); - - - GeoSpatial queries are also supported and are described more in the - section GeoSpatial Queries. - - Map-Reduce operations are also supported and are described more in - the section Map-Reduce. - -
- Querying documents in a collection - - We saw how to retrieve a single document using the findOne and - findById methods on MongoTemplate in previous sections which return a - single domain object. We can also query for a collection of documents to - be returned as a list of domain objects. Assuming that we have a number - of Person objects with name and age stored as documents in a collection - and that each person has an embedded account document with a balance. We - can now run a query using the following code. - - - Querying for documents using the MongoTemplate - - import static org.springframework.data.mongodb.core.query.Criteria.where; -import static org.springframework.data.mongodb.core.query.Query.query; - -… - -List<Person> result = mongoTemplate.find(query(where("age").lt(50) - .and("accounts.balance").gt(1000.00d)), Person.class); - - - All find methods take a Query object as a - parameter. This object defines the criteria and options used to perform - the query. The criteria is specified using a - Criteria object that has a static factory method - named where used to instantiate a new - Criteria object. We recommend using a static - import for - org.springframework.data.mongodb.core.query.Criteria.where - and Query.query to make the query more - readable. - - This query should return a list of Person - objects that meet the specified criteria. The - Criteria class has the following methods that - correspond to the operators provided in MongoDB. - - As you can see most methods return the - Criteria object to provide a fluent style for the - API. - -
- Methods for the Criteria class - - - - - Criteria all - (Object o)Creates a criterion - using the $all operator - - - - Criteria and - (String key) Adds a chained - Criteria with the specified - key to the current - Criteria and returns the newly created - one - - - - Criteria andOperator (Criteria... - criteria)Creates an and query using the - $and operator for all of the provided - criteria (requires MongoDB 2.0 or later) - - - - Criteria elemMatch (Criteria c) - Creates a criterion using the - $elemMatch operator - - - - Criteria exists - (boolean b) Creates a criterion - using the $exists operator - - - - Criteria gt - (Object o)Creates a criterion - using the $gt operator - - - - Criteria gte - (Object o)Creates a criterion - using the $gte operator - - - - Criteria in - (Object... o) Creates a criterion - using the $in operator for a varargs - argument. - - - - Criteria in - (Collection<?> collection) - Creates a criterion using the $in - operator using a collection - - - - Criteria is - (Object o)Creates a criterion - using the $is operator - - - - Criteria lt - (Object o)Creates a criterion - using the $lt operator - - - - Criteria lte - (Object o)Creates a criterion - using the $lte operator - - - - Criteria mod - (Number value, Number - remainder)Creates a criterion using the - $mod operator - - - - Criteria ne - (Object o)Creates a criterion - using the $ne operator - - - - Criteria nin - (Object... o) Creates a criterion - using the $nin operator - - - - Criteria norOperator (Criteria... - criteria)Creates an nor query using the - $nor operator for all of the provided - criteria - - - - Criteria not - ()Creates a criterion using the - $not meta operator which affects the clause - directly following - - - - Criteria orOperator (Criteria... - criteria)Creates an or query using the - $or operator for all of the provided - criteria - - - - Criteria regex - (String re) Creates a criterion - using a $regex - - - - Criteria size - (int s)Creates a criterion using - the $size operator - - - - Criteria type - (int t)Creates a criterion using - the $type operator - - - -
- - There are also methods on the Criteria class for geospatial - queries. Here is a listing but look at the section on GeoSpatial Queries to see them in - action. - - - - Criteria withinCenter - (Circle circle) Creates a geospatial - criterion using $within $center operators - - - - Criteria withinCenterSphere (Circle circle) - Creates a geospatial criterion using $within - $center operators. This is only available for MongoDB 1.7 - and higher. - - - - Criteria withinBox - (Box box) Creates a geospatial - criterion using a $within $box operation - - - - - Criteria near - (Point point) Creates a geospatial - criterion using a $near operation - - - - Criteria nearSphere - (Point point) Creates a geospatial - criterion using $nearSphere$center operations. - This is only available for MongoDB 1.7 and higher. - - - - Criteria maxDistance - (double maxDistance) Creates a - geospatial criterion using the $maxDistance - operation, for use with $near. - - - - The Query class has some additional methods - used to provide options for the query. - -
- Methods for the Query class - - - - - Query addCriteria - (Criteria criteria) used to add - additional criteria to the query - - - - Field fields - () used to define fields to be - included in the query results - - - - Query limit - (int limit) used to limit the - size of the returned results to the provided limit (used for - paging) - - - - Query skip - (int skip) used to skip the - provided number of documents in the results (used for - paging) - - - - Sort sort - () used to provide sort - definition for the results - - - -
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- Methods for querying for documents - - The query methods need to specify the target type T that will be - returned and they are also overloaded with an explicit collection name - for queries that should operate on a collection other than the one - indicated by the return type. - - - - findAll Query for a list - of objects of type T from the collection. - - - - findOne Map the results of - an ad-hoc query on the collection to a single instance of an - object of the specified type. - - - - findById Return an object - of the given id and target class. - - - - find Map the results of an - ad-hoc query on the collection to a List of the specified - type. - - - - findAndRemove Map the - results of an ad-hoc query on the collection to a single instance - of an object of the specified type. The first document that - matches the query is returned and also removed from the collection - in the database. - - -
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- GeoSpatial Queries - - MongoDB supports GeoSpatial queries through the use of operators - such as $near, $within, and - $nearSphere. Methods specific to geospatial queries - are available on the Criteria class. There are - also a few shape classes, Box, - Circle, and Point that are - used in conjunction with geospatial related - Criteria methods. - - To understand how to perform GeoSpatial queries we will use the - following Venue class taken from the integration tests.which relies on - using the rich MappingMongoConverter. - - @Document(collection="newyork") -public class Venue { - - @Id - private String id; - private String name; - private double[] location; - - @PersistenceConstructor - Venue(String name, double[] location) { - super(); - this.name = name; - this.location = location; - } - - public Venue(String name, double x, double y) { - super(); - this.name = name; - this.location = new double[] { x, y }; - } - - public String getName() { - return name; - } - - public double[] getLocation() { - return location; - } - - @Override - public String toString() { - return "Venue [id=" + id + ", name=" + name + ", location=" - + Arrays.toString(location) + "]"; - } -} - - To find locations within a Circle, the - following query can be used. - - Circle circle = new Circle(-73.99171, 40.738868, 0.01); -List<Venue> venues = - template.find(new Query(Criteria.where("location").withinCenter(circle)), Venue.class); - - To find venues within a Circle using - spherical coordinates the following query can be used - - Circle circle = new Circle(-73.99171, 40.738868, 0.003712240453784); -List<Venue> venues = - template.find(new Query(Criteria.where("location").withinCenterSphere(circle)), Venue.class); - - To find venues within a Box the following - query can be used - - //lower-left then upper-right -Box box = new Box(new Point(-73.99756, 40.73083), new Point(-73.988135, 40.741404)); -List<Venue> venues = - template.find(new Query(Criteria.where("location").withinBox(box)), Venue.class); - - To find venues near a Point, the following - query can be used - - Point point = new Point(-73.99171, 40.738868); -List<Venue> venues = - template.find(new Query(Criteria.where("location").near(point).maxDistance(0.01)), Venue.class); - - To find venues near a Point using spherical - coordines the following query can be used - - Point point = new Point(-73.99171, 40.738868); -List<Venue> venues = - template.find(new Query( - Criteria.where("location").nearSphere(point).maxDistance(0.003712240453784)), - Venue.class); - - -
- Geo near queries - - MongoDB supports querying the database for geo locations and - calculation the distance from a given origin at the very same time. - With geo-near queries it's possible to express queries like: "find all - restaurants in the surrounding 10 miles". To do so - MongoOperations provides - geoNear(…) methods taking a - NearQuery as argument as well as the already - familiar entity type and collection - - Point location = new Point(-73.99171, 40.738868); -NearQuery query = NearQuery.near(location).maxDistance(new Distance(10, Metrics.MILES)); - -GeoResults<Restaurant> = operations.geoNear(query, Restaurant.class); - - As you can see we use the NearQuery - builder API to set up a query to return all - Restaurant instances surrounding the given - Point by 10 miles maximum. The - Metrics enum used here actually implements an - interface so that other metrics could be plugged into a distance as - well. A Metric is backed by a - multiplier to transform the distance value of the given metric into - native distances. The sample shown here would consider the 10 to be - miles. Using one of the pre-built in metrics (miles and kilometers) - will automatically trigger the spherical flag to be set on the query. - If you want to avoid that, simply hand in plain - double values into - maxDistance(…). For more information see the - JavaDoc of NearQuery and - Distance. - - The geo near operations return a - GeoResults wrapper object that encapsulates - GeoResult instances. The wrapping - GeoResults allows to access the average - distance of all results. A single GeoResult - object simply carries the entity found plus its distance from the - origin. -
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- Full Text Queries - - Since mongodb 2.6 full text queries can be excuted using the - $text operator. Methods and operations specific for - full text queries are available in TextQuery and - TextCriteria. When doing full text search please - refer to the mongodb - reference for its behavior and limitations. - - - Full Text Search - - Bevore we are actually able to use full text search we have to - ensure to set up the search index correctly. Please refer to section - Text Index for - creating index structures. - - db.foo.ensureIndex( -{ - title : "text", - content : "text" -}, -{ - weights : { - title : 3 - } -} -) - - - A query searching for coffee cake, sorted by - relevance according to the weights can be defined - and executed as: - - Query query = TextQuery.searching(new TextCriteria().matchingAny("coffee", "cake")).sortByScore(); -List<Document> page = template.find(query, Document.class); - - - Exclusion of search terms can directly be done by prefixing the - term with - or using - notMatching - - // search for 'coffee' and not 'cake' -TextQuery.searching(new TextCriteria().matching("coffee").matching("-cake")); -TextQuery.searching(new TextCriteria().matching("coffee").notMatching("cake")); - - - As TextCriteria.matching takes the - provided term as is. Therefore phrases can be defined by putting them - between double quotes (eg. \"coffee cake\") or - using TextCriteria.phrase. - - // search for phrase 'coffee cake' -TextQuery.searching(new TextCriteria().matching("\"coffee cake\"")); -TextQuery.searching(new TextCriteria().phrase("coffee cake")); - - -
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- Map-Reduce Operations - - You can query MongoDB using Map-Reduce which is useful for batch - processing, data aggregation, and for when the query language doesn't - fulfill your needs. - - Spring provides integration with MongoDB's map reduce by providing - methods on MongoOperations to simplify the creation and execution of - Map-Reduce operations. It can convert the results of a Map-Reduce - operation to a POJO also integrates with Spring's Resource - abstraction abstraction. This will let you place your JavaScript - files on the file system, classpath, http server or any other Spring - Resource implementation and then reference the JavaScript resources via an - easy URI style syntax, e.g. 'classpath:reduce.js;. Externalizing - JavaScript code in files is often preferable to embedding them as Java - strings in your code. Note that you can still pass JavaScript code as Java - strings if you prefer. - -
- Example Usage - - To understand how to perform Map-Reduce operations an example from - the book 'MongoDB - The definitive guide' is used. In this example we - will create three documents that have the values [a,b], [b,c], and [c,d] - respectfully. The values in each document are associated with the key - 'x' as shown below. For this example assume these documents are in the - collection named "jmr1". { "_id" : ObjectId("4e5ff893c0277826074ec533"), "x" : [ "a", "b" ] } -{ "_id" : ObjectId("4e5ff893c0277826074ec534"), "x" : [ "b", "c" ] } -{ "_id" : ObjectId("4e5ff893c0277826074ec535"), "x" : [ "c", "d" ] } - A map function that will count the occurance of each letter - in the array for each document is shown below function () { - for (var i = 0; i < this.x.length; i++) { - emit(this.x[i], 1); - } -} The reduce function that will sum up the occurance of each - letter across all the documents is shown below function (key, values) { - var sum = 0; - for (var i = 0; i < values.length; i++) - sum += values[i]; - return sum; -} Executing this will result in a collection as shown below. - { "_id" : "a", "value" : 1 } -{ "_id" : "b", "value" : 2 } -{ "_id" : "c", "value" : 2 } -{ "_id" : "d", "value" : 1 } Assuming that the map and reduce - functions are located in map.js and reduce.js and bundled in your jar so - they are available on the classpath, you can execute a map-reduce - operation and obtain the results as shown below MapReduceResults<ValueObject> results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", ValueObject.class); -for (ValueObject valueObject : results) { - System.out.println(valueObject); -} The output of the above code is ValueObject [id=a, value=1.0] -ValueObject [id=b, value=2.0] -ValueObject [id=c, value=2.0] -ValueObject [id=d, value=1.0] The MapReduceResults class - implements Iterable and provides access to the - raw output, as well as timing and count statistics. The - ValueObject class is simply public class ValueObject { - - private String id; - private float value; - - public String getId() { - return id; - } - - public float getValue() { - return value; - } - - public void setValue(float value) { - this.value = value; - } - - @Override - public String toString() { - return "ValueObject [id=" + id + ", value=" + value + "]"; - } -} By default the output type of INLINE is used so you don't - have to specify an output collection. To specify additional map-reduce - options use an overloaded method that takes an additional - MapReduceOptions argument. The class - MapReduceOptions has a fluent API so adding - additional options can be done in a very compact syntax. Here an example - that sets the output collection to "jmr1_out". Note that setting only - the output collection assumes a default output type of REPLACE. - MapReduceResults<ValueObject> results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", - new MapReduceOptions().outputCollection("jmr1_out"), ValueObject.class); - There is also a static import import static - org.springframework.data.mongodb.core.mapreduce.MapReduceOptions.options; - that can be used to make the syntax slightly more compact - MapReduceResults<ValueObject> results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", - options().outputCollection("jmr1_out"), ValueObject.class); - You can also specify a query to reduce the set of data that will be used - to feed into the map-reduce operation. This will remove the document - that contains [a,b] from consideration for map-reduce operations. - Query query = new Query(where("x").ne(new String[] { "a", "b" })); -MapReduceResults<ValueObject> results = mongoOperations.mapReduce(query, "jmr1", "classpath:map.js", "classpath:reduce.js", - options().outputCollection("jmr1_out"), ValueObject.class); - Note that you can specify additional limit and sort values as well on - the query but not skip values. -
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- Group Operations - - As an alternative to using Map-Reduce to perform data aggregation, - you can use the group - operation which feels similar to using SQL's group by query style, - so it may feel more approachable vs. using Map-Reduce. Using the group - operations does have some limitations, for example it is not supported in - a shareded environment and it returns the full result set in a single BSON - object, so the result should be small, less than 10,000 keys. - - Spring provides integration with MongoDB's group operation by - providing methods on MongoOperations to simplify the creation and - execution of group operations. It can convert the results of the group - operation to a POJO and also integrates with Spring's Resource - abstraction abstraction. This will let you place your JavaScript - files on the file system, classpath, http server or any other Spring - Resource implementation and then reference the JavaScript resources via an - easy URI style syntax, e.g. 'classpath:reduce.js;. Externalizing - JavaScript code in files if often preferable to embedding them as Java - strings in your code. Note that you can still pass JavaScript code as Java - strings if you prefer. - -
- Example Usage - - In order to understand how group operations work the following - example is used, which is somewhat artificial. For a more realistic - example consult the book 'MongoDB - The definitive guide'. A collection - named "group_test_collection" created with the following rows. - - { "_id" : ObjectId("4ec1d25d41421e2015da64f1"), "x" : 1 } -{ "_id" : ObjectId("4ec1d25d41421e2015da64f2"), "x" : 1 } -{ "_id" : ObjectId("4ec1d25d41421e2015da64f3"), "x" : 2 } -{ "_id" : ObjectId("4ec1d25d41421e2015da64f4"), "x" : 3 } -{ "_id" : ObjectId("4ec1d25d41421e2015da64f5"), "x" : 3 } -{ "_id" : ObjectId("4ec1d25d41421e2015da64f6"), "x" : 3 } - - We would like to group by the only field in each row, the 'x' - field and aggregate the number of times each specific value of 'x' - occurs. To do this we need to create an initial document that contains - our count variable and also a reduce function which will increment it - each time it is encountered. The Java code to execute the group - operation is shown below - - GroupByResults<XObject> results = mongoTemplate.group("group_test_collection", - GroupBy.key("x").initialDocument("{ count: 0 }").reduceFunction("function(doc, prev) { prev.count += 1 }"), - XObject.class); - - The first argument is the name of the collection to run the group - operation over, the second is a fluent API that specifies properties of - the group operation via a GroupBy class. In this - example we are using just the intialDocument - and reduceFunction methods. You can also - specify a key-function, as well as a finalizer as part of the fluent - API. If you have multiple keys to group by, you can pass in a comma - separated list of keys. - - The raw results of the group operation is a JSON document that - looks like this - - { - "retval" : [ { "x" : 1.0 , "count" : 2.0} , - { "x" : 2.0 , "count" : 1.0} , - { "x" : 3.0 , "count" : 3.0} ] , - "count" : 6.0 , - "keys" : 3 , - "ok" : 1.0 -} - - The document under the "retval" field is mapped onto the third - argument in the group method, in this case XObject which is shown - below. - - public class XObject { - - private float x; - - private float count; - - - public float getX() { - return x; - } - - public void setX(float x) { - this.x = x; - } - - public float getCount() { - return count; - } - - public void setCount(float count) { - this.count = count; - } - - @Override - public String toString() { - return "XObject [x=" + x + " count = " + count + "]"; - } -} - - You can also obtain the raw result as a - DbObject by calling the method - getRawResults on the - GroupByResults class. - - There is an additional method overload of the group method on - MongoOperations which lets you specify a - Criteria object for selecting a subset of the - rows. An example which uses a Criteria object, - with some syntax sugar using static imports, as well as referencing a - key-function and reduce function javascript files via a Spring Resource - string is shown below. - - import static org.springframework.data.mongodb.core.mapreduce.GroupBy.keyFunction; -import static org.springframework.data.mongodb.core.query.Criteria.where; - -GroupByResults<XObject> results = mongoTemplate.group(where("x").gt(0), - "group_test_collection", - keyFunction("classpath:keyFunction.js").initialDocument("{ count: 0 }").reduceFunction("classpath:groupReduce.js"), XObject.class); -
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- Aggregation Framework Support - - Spring Data MongoDB provides support for the Aggregation Framework - introduced to MongoDB in version 2.2. - - The MongoDB Documentation describes the Aggregation - Framework as follows:The MongoDB aggregation framework - provides a means to calculate aggregated values without having to use - map-reduce. While map-reduce is powerful, it is often more difficult than - necessary for many simple aggregation tasks, such as totaling or averaging - field values. - - For further information see the full reference - documentation of the aggregation framework and other data - aggregation tools for MongoDB. - -
- Basic Concepts - - The Aggregation Framework support in Spring Data MongoDB is based - on the following key abstractions Aggregation, - AggregationOperation and - AggregationResults. - - - - Aggregation - - An Aggregation represents a MongoDB - aggregate operation and holds the - description of the aggregation pipline instructions. Aggregations - are created by inoking the appropriate - newAggregation(…) static factory Method of the - Aggregation class which takes the list of - AggregateOperation as a parameter next to the - optional input class. - - The actual aggregate operation is executed by the - aggregate method of the - MongoTemplate which also takes the desired - output class as parameter. - - - - AggregationOperation - - An AggregationOperation represents a - MongoDB aggregation pipeline operation and describes the processing - that should be performed in this aggregation step. Although one - could manually create an AggregationOperation - the recommended way to construct an - AggregateOperation is to use the static - factory methods provided by the Aggregate - class. - - - - AggregationResults - - AggregationResults is the container for - the result of an aggregate operation. It provides access to the raw - aggregation result in the form of an - DBObject, to the mapped objects and - information which performed the aggregation. - - - - The canonical example for using the Spring Data MongoDB support - for the MongoDB Aggregation Framework looks as follows: - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -Aggregation agg = newAggregation( - pipelineOP1(), - pipelineOP2(), - pipelineOPn() -); - -AggregationResults<OutputType> results = mongoTemplate.aggregate(agg, "INPUT_COLLECTION_NAME", OutputType.class); -List<OutputType> mappedResult = results.getMappedResults(); - - - Note that if you provide an input class as the first parameter to - the newAggregation method the - MongoTemplate will derive the name of the input - collection from this class. Otherwise if you don't not specify an input - class you must provide the name of the input collection explicitly. If - an input-class and an input-collection is provided the latter takes - precedence. -
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- Supported Aggregation Operations - - The MongoDB Aggregation Framework provides the following types of - Aggregation Operations: - - - - Pipeline Aggregation Operators - - - - Group Aggregation Operators - - - - Boolean Aggregation Operators - - - - Comparison Aggregation Operators - - - - Arithmetic Aggregation Operators - - - - String Aggregation Operators - - - - Date Aggregation Operators - - - - Conditional Aggregation Operators - - - - At the time of this writing we provide support for the following - Aggregation Operations in Spring Data MongoDB. - - - Aggregation Operations currently supported by Spring Data - MongoDB - - - - - Pipeline Aggregation Operators - - project, skip, limit, unwind, group, sort, - geoNear - - - - Group Aggregation Operators - - addToSet, first, last, max, min, avg, push, sum, - (*count) - - - - Arithmetic Aggregation Operators - - add (*via plus), subtract (*via minus), multiply, divide, - mod - - - - Comparison Aggregation Operators - - eq (*via: is), gt, gte, lt, lte, ne - - - -
- - Note that the aggregation operations not listed here are currently - not supported by Spring Data MongoDB. Comparison aggregation operators - are expressed as Criteria expressions. - - *) The operation is mapped or added by Spring Data MongoDB. -
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- Projection Expressions - - Projection expressions are used to define the fields that are the - outcome of a particular aggregation step. Projection expressions can be - defined via the project method of the - Aggregate class. - - - Projection expression examples - - project("name", "netPrice") // will generate {$project: {name: 1, netPrice: 1}} -project().and("foo").as("bar") // will generate {$project: {bar: $foo}} -project("a","b").and("foo").as("bar") // will generate {$project: {a: 1, b: 1, bar: $foo}} - - Note that more examples for project operations can be found in - the AggregationTests class. - - - Note that further details regarding the projection expressions can - be found in the corresponding - section of the MongoDB Aggregation Framework reference - documentation. - -
- Spring Expression Support in Projection Expressions - - As of Version 1.4.0 we support the use of SpEL expression in - projection expressions via the andExpression - method of the ProjectionOperation class. This - allows you to define the desired expression as a SpEL expression which - is translated into a corresponding MongoDB projection expression part - on query execution. This makes it much easier to express complex - calculations. - - - Complex calculations with SpEL expressions - - The following SpEL expression: - - 1 + (q + 1) / (q - 1) - - will be translated into the following projection expression - part: - - { "$add" : [ 1, { - "$divide" : [ { - "$add":["$q", 1]}, { - "$subtract":[ "$q", 1]} - ] -}]} - - - Have a look at an example in more context in and . You can find more - usage examples for supported SpEL expression constructs in - SpelExpressionTransformerUnitTests. -
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- Aggregation Framework Examples - - The following examples demonstrate the usage patterns for the - MongoDB Aggregation Framework with Spring Data MongoDB. - - - Aggregation Framework Example 1 - - In this introductory example we want to aggregate a list of tags - to get the occurrence count of a particular tag from a MongoDB - collection called "tags" sorted by the occurrence count - in descending order. This example demonstrates the usage of grouping, - sorting, projections (selection) and unwinding (result - splitting). - - class TagCount { - String tag; - int n; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -Aggregation agg = newAggregation( - project("tags"), - unwind("tags"), - group("tags").count().as("n"), - project("n").and("tag").previousOperation(), - sort(DESC, "n") -); - -AggregationResults<TagCount> results = mongoTemplate.aggregate(agg, "tags", TagCount.class); -List<TagCount> tagCount = results.getMappedResults(); - - - - - In order to do this we first create a new aggregation via the - newAggregation static factory method to - which we pass a list of aggregation operations. These aggregate - operations define the aggregation pipeline of our - Aggregation. - - - - As a second step we select the "tags" field - (which is an array of strings) from the input collection with the - project operation. - - - - In a third step we use the unwind - operation to generate a new document for each tag within the - "tags" array. - - - - In the forth step we use the group - operation to define a group for each "tags"-value for - which we aggregate the occurrence count via the - count aggregation operator and collect the - result in a new field called "n". - - - - As a fifth step we select the field "n" and - create an alias for the id-field generated from the previous group - operation (hence the call to previousOperation()) with - the name "tag". - - - - As the sixth step we sort the resulting list of tags by their - occurrence count in descending order via the - sort operation. - - - - Finally we call the aggregate Method - on the MongoTemplate in order to let MongoDB perform the acutal - aggregation operation with the created - Aggregation as an argument. - - - - Note that the input collection is explicitly specified as the - "tags" parameter to the aggregate - Method. If the name of the input collection is not specified explicitly, - it is derived from the input-class passed as first parameter to the - newAggreation Method. - - - Aggregation Framework Example 2 - - This example is based on the Largest - and Smallest Cities by State example from the MongoDB - Aggregation Framework documentation. We added additional sorting to - produce stable results with different MongoDB versions. Here we want - to return the smallest and largest cities by population for each - state, using the aggregation framework. This example demonstrates the - usage of grouping, sorting and projections (selection). - - class ZipInfo { - String id; - String city; - String state; - @Field("pop") int population; - @Field("loc") double[] location; -} - -class City { - String name; - int population; -} - -class ZipInfoStats { - String id; - String state; - City biggestCity; - City smallestCity; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -TypedAggregation<ZipInfo> aggregation = newAggregation(ZipInfo.class, - group("state", "city") - .sum("population").as("pop"), - sort(ASC, "pop", "state", "city"), - group("state") - .last("city").as("biggestCity") - .last("pop").as("biggestPop") - .first("city").as("smallestCity") - .first("pop").as("smallestPop"), - project() - .and("state").previousOperation() - .and("biggestCity") - .nested(bind("name", "biggestCity").and("population", "biggestPop")) - .and("smallestCity") - .nested(bind("name", "smallestCity").and("population", "smallestPop")), - sort(ASC, "state") -); - -AggregationResults<ZipInfoStats> result = mongoTemplate.aggregate(aggregation, ZipInfoStats.class); -ZipInfoStats firstZipInfoStats = result.getMappedResults().get(0); - - - - - - The class ZipInfo maps the structure of - the given input-collection. The class - ZipInfoStats defines the structure in the - desired output format. - - - - As a first step we use the group - operation to define a group from the input-collection. The grouping - criteria is the combination of the fields "state" and - "city" which forms the id structure of the group. We - aggregate the value of the "population" property from - the grouped elements with by using the sum - operator saving the result in the field "pop". - - - - In a second step we use the sort - operation to sort the intermediate-result by the fields - "pop", "state" and "city" in - ascending order, such that the smallest city is at the top and the - biggest city is at the bottom of the result. Note that the sorting - on "state" and "city" is implicitly performed against - the group id fields which Spring Data MongoDB took care of. - - - - In the third step we use a group - operation again to group the intermediate result by - "state". Note that "state" again - implicitly references an group-id field. We select the name and the - population count of the biggest and smallest city with calls to the - last(…) and first(...) operator - respectively via the project - operation. - - - - As the forth step we select the "state" field - from the previous group operation. Note - that "state" again implicitly references an group-id - field. As we do not want an implicit generated id to appear, we - exclude the id from the previous operation via - and(previousOperation()).exclude(). As we want to - populate the nested City structures in our - output-class accordingly we have to emit appropriate sub-documents - with the nested method. - - - - Finally as the fifth step we sort the resulting list of - StateStats by their state name in ascending - order via the sort operation. - - - - Note that we derive the name of the input-collection from the - ZipInfo-class passed as first parameter to the - newAggregation-Method. - - - Aggregation Framework Example 3 - - This example is based on the States - with Populations Over 10 Million example from the MongoDB - Aggregation Framework documentation. We added additional sorting to - produce stable results with different MongoDB versions. Here we want - to return all states with a population greater than 10 million, using - the aggregation framework. This example demonstrates the usage of - grouping, sorting and matching (filtering). - - class StateStats { - @Id String id; - String state; - @Field("totalPop") int totalPopulation; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -TypedAggregation<ZipInfo> agg = newAggregation(ZipInfo.class, - group("state").sum("population").as("totalPop"), - sort(ASC, previousOperation(), "totalPop"), - match(where("totalPop").gte(10 * 1000 * 1000)) -); - -AggregationResults<StateStats> result = mongoTemplate.aggregate(agg, StateStats.class); -List<StateStats> stateStatsList = result.getMappedResults(); - - - - - As a first step we group the input collection by the - "state" field and calculate the sum of the - "population" field and store the result in the new - field "totalPop". - - - - In the second step we sort the intermediate result by the - id-reference of the previous group operation in addition to the - "totalPop" field in ascending order. - - - - Finally in the third step we filter the intermediate result by - using a match operation which accepts a - Criteria query as an argument. - - - - Note that we derive the name of the input-collection from the - ZipInfo-class passed as first parameter to the - newAggregation-Method. - - - Aggregation Framework Example 4 - - This example demonstrates the use of simple arithmetic - operations in the projection operation. - - class Product { - String id; - String name; - double netPrice; - int spaceUnits; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -TypedAggregation<Product> agg = newAggregation(Product.class, - project("name", "netPrice") - .and("netPrice").plus(1).as("netPricePlus1") - .and("netPrice").minus(1).as("netPriceMinus1") - .and("netPrice").multiply(1.19).as("grossPrice") - .and("netPrice").divide(2).as("netPriceDiv2") - .and("spaceUnits").mod(2).as("spaceUnitsMod2") -); - -AggregationResults<DBObject> result = mongoTemplate.aggregate(agg, DBObject.class); -List<DBObject> resultList = result.getMappedResults(); - - - Note that we derive the name of the input-collection from the - Product-class passed as first parameter to the - newAggregation-Method. - - - Aggregation Framework Example 5 - - This example demonstrates the use of simple arithmetic - operations derived from SpEL Expressions in the projection - operation. - - class Product { - String id; - String name; - double netPrice; - int spaceUnits; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -TypedAggregation<Product> agg = newAggregation(Product.class, - project("name", "netPrice") - .andExpression("netPrice + 1").as("netPricePlus1") - .andExpression("netPrice - 1").as("netPriceMinus1") - .andExpression("netPrice / 2").as("netPriceDiv2") - .andExpression("netPrice * 1.19").as("grossPrice") - .andExpression("spaceUnits % 2").as("spaceUnitsMod2") - .andExpression("(netPrice * 0.8 + 1.2) * 1.19").as("grossPriceIncludingDiscountAndCharge") - -); - -AggregationResults<DBObject> result = mongoTemplate.aggregate(agg, DBObject.class); -List<DBObject> resultList = result.getMappedResults(); - - - - Aggregation Framework Example 6 - - This example demonstrates the use of complex arithmetic - operations derived from SpEL Expressions in the projection - operation. - - Note: The additional parameters passed to the - addExpression Method can be referenced via - indexer expressions according to their position. In this example we - reference the parameter shippingCosts which is the - first parameter of the parameters array via [0]. External - parameter expressions are replaced with their respective values when - the SpEL expression is transformed into a MongoDB aggregation - framework expression. - - class Product { - String id; - String name; - double netPrice; - int spaceUnits; -} - - import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; - -double shippingCosts = 1.2; - -TypedAggregation<Product> agg = newAggregation(Product.class, - project("name", "netPrice") - .andExpression("(netPrice * (1-discountRate) + [0]) * (1+taxRate)", shippingCosts).as("salesPrice") -); - -AggregationResults<DBObject> result = mongoTemplate.aggregate(agg, DBObject.class); -List<DBObject> resultList = result.getMappedResults(); - - - Note that we can also refer to other fields of the document within - the SpEL expression. -
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- Overriding default mapping with custom converters - - In order to have more fine grained control over the mapping process - you can register Spring converters with the - MongoConverter implementations such as the - MappingMongoConverter. - - The MappingMongoConverter checks to see if - there are any Spring converters that can handle a specific class before - attempting to map the object itself. To 'hijack' the normal mapping - strategies of the MappingMongoConverter, perhaps - for increased performance or other custom mapping needs, you first need to - create an implementation of the Spring - Converter interface and then register it - with the MappingConverter. - - - For more information on the Spring type conversion service see the - reference docs here. - - -
- Saving using a registered Spring Converter - - An example implementation of the - Converter that converts from a Person - object to a com.mongodb.DBObject is shown - below - - import org.springframework.core.convert.converter.Converter; - -import com.mongodb.BasicDBObject; -import com.mongodb.DBObject; - -public class PersonWriteConverter implements Converter<Person, DBObject> { - - public DBObject convert(Person source) { - DBObject dbo = new BasicDBObject(); - dbo.put("_id", source.getId()); - dbo.put("name", source.getFirstName()); - dbo.put("age", source.getAge()); - return dbo; - } -} -
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- Reading using a Spring Converter - - An example implementation of a Converter that converts from a - DBObject ot a Person object is shownn below - - public class PersonReadConverter implements Converter<DBObject, Person> { - - public Person convert(DBObject source) { - Person p = new Person((ObjectId) source.get("_id"), (String) source.get("name")); - p.setAge((Integer) source.get("age")); - return p; - } -} -
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- Registering Spring Converters with the MongoConverter - - The Mongo Spring namespace provides a convenience way to register - Spring Converters with the - MappingMongoConverter. The configuration snippet - below shows how to manually register converter beans as well as - configuring the wrapping MappingMongoConverter - into a MongoTemplate. - - <mongo:db-factory dbname="database"/> - -<mongo:mapping-converter> - <mongo:custom-converters> - <mongo:converter ref="readConverter"/> - <mongo:converter> - <bean class="org.springframework.data.mongodb.test.PersonWriteConverter"/> - </mongo:converter> - </mongo:custom-converters> -</mongo:mapping-converter> - -<bean id="readConverter" class="org.springframework.data.mongodb.test.PersonReadConverter"/> - -<bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> - <constructor-arg name="mongoDbFactory" ref="mongoDbFactory"/> - <constructor-arg name="mongoConverter" ref="mappingConverter"/> -</bean> - - You can also use the base-package attribute of the - custom-converters element to enable classpath scanning for all - Converter and - GenericConverter implementations below - the given package. - - <mongo:mapping-converter> - <mongo:custom-converters base-package="com.acme.**.converters" /> -</mongo:mapping-converter> -
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- Converter disambiguation - - Generally we inspect the Converter - implementations for the source and target types they convert from and - to. Depending on whether one of those is a type MongoDB can handle - natively we will register the converter instance as reading or writing - one. Have a look at the following samples: - - // Write converter as only the target type is one Mongo can handle natively -class MyConverter implements Converter<Person, String> { … } - -// Read converter as only the source type is one Mongo can handle natively -class MyConverter implements Converter<String, Person> { … } - - In case you write a Converter whose - source and target type are native Mongo types there's no way for us to - determine whether we should consider it as reading or writing converter. - Registering the converter instance as both might lead to unwanted - results then. E.g. a Converter<String, - Long> is ambiguous although it probably does not make - sense to try to convert all Strings into - Longs when writing. To be generally able to force - the infrastructure to register a converter for one way only we provide - @ReadingConverter as well as - @WritingConverter to be used at the - converter implementation. -
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- Index and Collection management - - MongoTemplate provides a few methods for - managing indexes and collections. These are collected into a helper - interface called IndexOperations. You - access these operations by calling the method - indexOps and pass in either the collection name - or the java.lang.Class of your entity (the collection - name will be derived from the .class either by name or via annotation - metadata). - - The IndexOperations interface is - shown below - - public interface IndexOperations { - - void ensureIndex(IndexDefinition indexDefinition); - - void dropIndex(String name); - - void dropAllIndexes(); - - void resetIndexCache(); - - List<IndexInfo> getIndexInfo(); -} - -
- Methods for creating an Index - - We can create an index on a collection to improve query - performance. - - - Creating an index using the MongoTemplate - - mongoTemplate.indexOps(Person.class).ensureIndex(new Index().on("name",Order.ASCENDING)); - - - - - ensureIndex Ensure that an - index for the provided IndexDefinition exists for the - collection. - - - - You can create standard, geospatial and text indexes using the - classes IndexDefinition, - GeoSpatialIndex and - TextIndexDefinition. For example, given the Venue - class defined in a previous section, you would declare a geospatial - query as shown below. - - mongoTemplate.indexOps(Venue.class).ensureIndex(new GeospatialIndex("location")); -
- -
- Accessing index information - - The IndexOperations interface has the method getIndexInfo that - returns a list of IndexInfo objects. This contains all the indexes - defined on the collectcion. Here is an example that defines an index on - the Person class that has age property. - - template.indexOps(Person.class).ensureIndex(new Index().on("age", Order.DESCENDING).unique(Duplicates.DROP)); - -List<IndexInfo> indexInfoList = template.indexOps(Person.class).getIndexInfo(); - -// Contains -// [IndexInfo [fieldSpec={_id=ASCENDING}, name=_id_, unique=false, dropDuplicates=false, sparse=false], -// IndexInfo [fieldSpec={age=DESCENDING}, name=age_-1, unique=true, dropDuplicates=true, sparse=false]] - -
- -
- Methods for working with a Collection - - It's time to look at some code examples showing how to use the - MongoTemplate. First we look at creating our - first collection. - - - Working with collections using the MongoTemplate - - DBCollection collection = null; -if (!mongoTemplate.getCollectionNames().contains("MyNewCollection")) { - collection = mongoTemplate.createCollection("MyNewCollection"); -} - -mongoTemplate.dropCollection("MyNewCollection"); - - - - - getCollectionNames Returns - a set of collection names. - - - - collectionExists Check to - see if a collection with a given name exists. - - - - createCollection Create an - uncapped collection - - - - dropCollection Drop the - collection - - - - getCollection Get a - collection by name, creating it if it doesn't exist. - - -
-
- -
- Executing Commands - - You can also get at the MongoDB driver's DB.command( - ) method using the executeCommand(…) - methods on MongoTemplate. These will also perform - exception translation into Spring's - DataAccessException hierarchy. - -
- Methods for executing commands - - - - CommandResult executeCommand (DBObject command) - Execute a MongoDB command. - - - - CommandResult executeCommand (String - jsonCommand) Execute the a MongoDB command expressed as - a JSON string. - - -
-
- -
- Lifecycle Events - - Built into the MongoDB mapping framework are several - org.springframework.context.ApplicationEvent events - that your application can respond to by registering special beans in the - ApplicationContext. By being based off Spring's - ApplicationContext event infastructure this enables other products, such - as Spring Integration, to easily receive these events as they are a well - known eventing mechanism in Spring based applications. - - To intercept an object before it goes through the conversion process - (which turns your domain object into a - com.mongodb.DBObject), you'd register a subclass of - AbstractMongoEventListener that overrides the - onBeforeConvert method. When the event is dispatched, your - listener will be called and passed the domain object before it goes into - the converter. - - - public class BeforeConvertListener extends AbstractMongoEventListener<Person> { - @Override - public void onBeforeConvert(Person p) { - ... does some auditing manipulation, set timestamps, whatever ... - } -} - - - To intercept an object before it goes into the database, you'd - register a subclass of - org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener - that overrides the onBeforeSave method. When the event is - dispatched, your listener will be called and passed the domain object and - the converted com.mongodb.DBObject. - - - public class BeforeSaveListener extends AbstractMongoEventListener<Person> { - @Override - public void onBeforeSave(Person p, DBObject dbo) { - … change values, delete them, whatever … - } -} - - - Simply declaring these beans in your Spring ApplicationContext will - cause them to be invoked whenever the event is dispatched. - - The list of callback methods that are present in - AbstractMappingEventListener are - - - - onBeforeConvert - called in - MongoTemplate insert, insertList and save operations before the object - is converted to a DBObject using a MongoConveter. - - - - onBeforeSave - called in MongoTemplate - insert, insertList and save operations before - inserting/saving the DBObject in the database. - - - - onAfterSave - called in MongoTemplate - insert, insertList and save operations after - inserting/saving the DBObject in the database. - - - - onAfterLoad - called in MongoTempnlate - find, findAndRemove, findOne and getCollection methods after the - DBObject is retrieved from the database. - - - - onAfterConvert - called in - MongoTempnlate find, findAndRemove, findOne and getCollection methods - after the DBObject retrieved from the database was converted to a - POJO. - - -
- -
- Exception Translation - - The Spring framework provides exception translation for a wide - variety of database and mapping technologies. This has traditionally been - for JDBC and JPA. The Spring support for MongoDB extends this feature to - the MongoDB Database by providing an implementation of the - org.springframework.dao.support.PersistenceExceptionTranslator - interface. - - The motivation behind mapping to Spring's consistent - data access exception hierarchy is that you are then able to write - portable and descriptive exception handling code without resorting to - coding against MongoDB error - codes. All of Spring's data access exceptions are inherited from - the root DataAccessException class so you can be - sure that you will be able to catch all database related exception within - a single try-catch block. Note, that not all exceptions thrown by the - MongoDB driver inherit from the MongoException class. The inner exception - and message are preserved so no information is lost. - - Some of the mappings performed by the - MongoExceptionTranslator are: com.mongodb.Network - to DataAccessResourceFailureException and - MongoException error codes 1003, 12001, 12010, - 12011, 12012 to InvalidDataAccessApiUsageException. - Look into the implementation for more details on the mapping. -
- -
- Execution callbacks - - One common design feature of all Spring template classes is that all - functionality is routed into one of the templates execute callback - methods. This helps ensure that exceptions and any resource management - that maybe required are performed consistency. While this was of much - greater need in the case of JDBC and JMS than with MongoDB, it still - offers a single spot for exception translation and logging to occur. As - such, using thexe execute callback is the preferred way to access the - MongoDB driver's DB and - DBCollection objects to perform uncommon operations - that were not exposed as methods on - MongoTemplate. - - Here is a list of execute callback methods. - - - - <T> T execute - (Class<?> entityClass, - CollectionCallback<T> action) Executes the given - CollectionCallback for the entity collection of the specified - class. - - - - <T> T execute - (String collectionName, - CollectionCallback<T> action) Executes the given - CollectionCallback on the collection of the given name. - - - - <T> T execute - (DbCallback<T> action) Spring Data - MongoDB provides support for the Aggregation Framework introduced to - MongoDB in version 2.2. Executes a DbCallback translating - any exceptions as necessary. - - - - <T> T execute - (String collectionName, DbCallback<T> - action) Executes a DbCallback on the collection of the - given name translating any exceptions as necessary. - - - - <T> T executeInSession - (DbCallback<T> action) Executes the given - DbCallback within the same connection to the database so as to - ensure consistency in a write heavy environment where you may read - the data that you wrote. - - - - Here is an example that uses the - CollectionCallback to return information - about an index - - boolean hasIndex = template.execute("geolocation", new CollectionCallbackBoolean>() { - public Boolean doInCollection(Venue.class, DBCollection collection) throws MongoException, DataAccessException { - List<DBObject> indexes = collection.getIndexInfo(); - for (DBObject dbo : indexes) { - if ("location_2d".equals(dbo.get("name"))) { - return true; - } - } - return false; - } -}); -
- -
- GridFS support - - MongoDB supports storing binary files inside it's filesystem GridFS. - Spring Data MongoDB provides a - GridFsOperations interface as well as the - according implementation GridFsTemplate to easily - interact with the filesystem. You can setup a - GridFsTemplate instance by handing it a - MongoDbFactory as well as a - MongoConverter: - - - JavaConfig setup for a GridFsTemplate - - class GridFsConfiguration extends AbstractMongoConfiguration { - - // … further configuration omitted - - @Bean - public GridFsTemplate gridFsTemplate() { - return new GridFsTemplate(mongoDbFactory(), mappingMongoConverter()); - } -} - - - An according XML configuration looks like this: - - - XML configuration for a GridFsTemplate - - <?xml version="1.0" encoding="UTF-8"?> -<beans xmlns="http://www.springframework.org/schema/beans" - xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" - xmlns:mongo="http://www.springframework.org/schema/data/mongo" - xsi:schemaLocation="http://www.springframework.org/schema/data/mongo - http://www.springframework.org/schema/data/mongo/spring-mongo.xsd - http://www.springframework.org/schema/beans - http://www.springframework.org/schema/beans/spring-beans.xsd"> - - <mongo:db-factory id="mongoDbFactory" dbname="database" /> - <mongo:mapping-converter id="converter" /> - - <bean class="org.springframework.data.mongodb.gridfs.GridFsTemplate"> - <constructor-arg ref="mongoDbFactory" /> - <constructor-arg ref="converter" /> - </bean> - -</beans> - - - The template can now be injected and used to perform storage and - retrieval operations. - - - Using GridFsTemplate to store files - - class GridFsClient { - - @Autowired - GridFsOperations operations; - - @Test - public void storeFileToGridFs { - - FileMetadata metadata = new FileMetadata(); - // populate metadata - Resource file = … // lookup File or Resource - - operations.store(file.getInputStream(), "filename.txt", metadata); - } -} - - - The store(…) operations take an - InputStream, a filename and optionally - metadata information about the file to store. The metadata can be an - arbitrary object which will be marshalled by the - MongoConverter configured with the - GridFsTemplate. Alternatively you can also provide - a DBObject as well. - - Reading files from the filesystem can either be achieved through the - find(…) or - getResources(…) methods. Let's have a look at the - find(…) methods first. You can either find a - single file matching a Query or multiple ones. To - easily define file queries we provide the - GridFsCriteria helper class. It provides static - factory methods to encapsulate default metadata fields (e.g. - whereFilename(), - whereContentType()) or the custom one through - whereMetaData(). - - - Using GridFsTemplate to query for files - - class GridFsClient { - - @Autowired - GridFsOperations operations; - - @Test - public void findFilesInGridFs { - List<GridFSDBFile> result = operations.find(query(whereFilename().is("filename.txt"))) - } -} - - - - Currently MongoDB does not support defining sort criterias when - retrieving files from GridFS. Thus any sort criterias defined on the - Query instance handed into the - find(…) method will be disregarded. - - - The other option to read files from the GridFs is using the methods - introduced by the ResourcePatternResolver - interface. They allow handing an Ant path into the method ar thus retrieve - files matching the given pattern. - - - Using GridFsTemplate to read files - - class GridFsClient { - - @Autowired - GridFsOperations operations; - - @Test - public void readFilesFromGridFs { - GridFsResources[] txtFiles = operations.getResources("*.txt"); - } -} - - - GridFsOperations extending - ResourcePatternResolver allows the - GridFsTemplate e.g. to be plugged into an - ApplicationContext to read Spring Config - files from a MongoDB. -
- diff --git a/src/main/asciidoc/index.adoc b/src/main/asciidoc/index.adoc new file mode 100644 index 000000000..e2c8630bf --- /dev/null +++ b/src/main/asciidoc/index.adoc @@ -0,0 +1,38 @@ += Spring Data MongoDB - Reference Documentation +Mark Pollack, Thomas Risberg, Oliver Gierke, Costin Leau, Jon Brisbin, Thomas Darimont, Christoph Strobl +:toc: +:spring-data-commons-docs: https://raw.githubusercontent.com/spring-projects/spring-data-commons/issue/DATACMNS-551/src/main/asciidoc +{version} + +NOTE: _Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically._ + +include::preface.adoc[] +include::introduction/introduction.adoc[] + +:leveloffset: 1 +include::introduction/requirements.adoc[] +include::introduction/getting-started.adoc[] +include::{spring-data-commons-docs}/repositories.adoc[] + +:leveloffset: 0 +[[reference]] += Reference Documentation + +:leveloffset: 1 +include::reference/introduction.adoc[] +include::reference/mongodb.adoc[] +include::reference/mongo-repositories.adoc[] +include::{spring-data-commons-docs}/auditing.adoc[] +include::reference/mapping.adoc[] +include::reference/cross-store.adoc[] +include::reference/logging.adoc[] +include::reference/jmx.adoc[] + +:leveloffset: 0 += Appendix + +:numbered!: +:leveloffset: 1 +include::{spring-data-commons-docs}/repository-namespace-reference.adoc[] +include::{spring-data-commons-docs}/repository-namespace-reference.adoc[] +include::{spring-data-commons-docs}/repository-query-keywords-reference.adoc[] diff --git a/src/main/asciidoc/introduction/getting-started.adoc b/src/main/asciidoc/introduction/getting-started.adoc new file mode 100644 index 000000000..77051a6a9 --- /dev/null +++ b/src/main/asciidoc/introduction/getting-started.adoc @@ -0,0 +1,24 @@ +[[get-started]] += Additional Help Resources + +Learning a new framework is not always straight forward. In this section, we try to provide what we think is an easy to follow guide for starting with Spring Data Document module. However, if you encounter issues or you are just looking for an advice, feel free to use one of the links below: + +[[get-started:help]] +== Support + +There are a few support options available: + +[[get-started:help:community]] +=== Community Forum + +Spring Data on Stackoverflow http://stackoverflow.com/questions/tagged/spring-data[Stackoverflow ] is a tag for all Spring Data (not just Document) users to share information and help each other. Note that registration is needed *only* for posting. + +[[get-started:help:professional]] +=== Professional Support + +Professional, from-the-source support, with guaranteed response time, is available from http://gopivotal.com/[Pivotal Sofware, Inc.], the company behind Spring Data and Spring. + +[[get-started:up-to-date]] +== Following Development + +For information on the Spring Data Mongo source code repository, nightly builds and snapshot artifacts please see the http://projects.spring.io/spring-data-mongodb/[Spring Data Mongo homepage]. You can help make Spring Data best serve the needs of the Spring community by interacting with developers through the Community on http://stackoverflow.com/questions/tagged/spring-data[Stackoverflow]. To follow developer activity look for the mailing list information on the Spring Data Mongo homepage. If you encounter a bug or want to suggest an improvement, please create a ticket on the Spring Data issue https://jira.spring.io/browse/DATAMONGO[tracker]. To stay up to date with the latest news and announcements in the Spring eco system, subscribe to the Spring Community http://spring.io[Portal]. Lastly, you can follow the SpringSource Data http://spring.io/blog[blog ]or the project team on Twitter (http://twitter.com/SpringData[SpringData]). diff --git a/src/main/asciidoc/introduction/introduction.adoc b/src/main/asciidoc/introduction/introduction.adoc new file mode 100644 index 000000000..210f82c9f --- /dev/null +++ b/src/main/asciidoc/introduction/introduction.adoc @@ -0,0 +1,26 @@ +[[introduction]] += Introduction + +This document is the reference guide for Spring Data - Document Support. It explains Document module concepts and semantics and the syntax for various stores namespaces. + +This section provides some basic introduction to Spring and Document database. The rest of the document refers only to Spring Data Document features and assumes the user is familiar with document databases such as MongoDB and CouchDB as well as Spring concepts. + +[[get-started:first-steps:spring]] +== Knowing Spring +Spring Data uses Spring framework's http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/spring-core.html[core] functionality, such as the http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/beans.html[IoC] container, http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/validation.html#core-convert[type conversion system], http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/expressions.html[expression language], http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/jmx.html[JMX integration], and portable http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/dao.html#dao-exceptions[DAO exception hierarchy]. While it is not important to know the Spring APIs, understanding the concepts behind them is. At a minimum, the idea behind IoC should be familiar for whatever IoC container you choose to use. + +The core functionality of the MongoDB and CouchDB support can be used directly, with no need to invoke the IoC services of the Spring Container. This is much like `JdbcTemplate` which can be used 'standalone' without any other services of the Spring container. To leverage all the features of Spring Data document, such as the repository support, you will need to configure some parts of the library using Spring. + +To learn more about Spring, you can refer to the comprehensive (and sometimes disarming) documentation that explains in detail the Spring Framework. There are a lot of articles, blog entries and books on the matter - take a look at the Spring framework http://spring.io/docs[home page ] for more information. + +[[get-started:first-steps:nosql]] +== Knowing NoSQL and Document databases +NoSQL stores have taken the storage world by storm. It is a vast domain with a plethora of solutions, terms and patterns (to make things worth even the term itself has multiple http://www.google.com/search?q=nosoql+acronym[meanings]). While some of the principles are common, it is crucial that the user is familiar to some degree with the stores supported by DATADOC. The best way to get acquainted to this solutions is to read their documentation and follow their examples - it usually doesn't take more then 5-10 minutes to go through them and if you are coming from an RDMBS-only background many times these exercises can be an eye opener. + +The jumping off ground for learning about MongoDB is http://www.mongodb.org/[www.mongodb.org]. Here is a list of other useful resources: + +* The http://docs.mongodb.org/manual/[manual] introduces MongoDB and contains links to getting started guides, reference documentation and tutorials. +* The http://try.mongodb.org/[online shell] provides a convenient way to interact with a MongoDB instance in combination with the online http://docs.mongodb.org/manual/tutorial/getting-started/[tutorial.] +* MongoDB http://docs.mongodb.org/ecosystem/drivers/java/[Java Language Center] +* Several http://www.mongodb.org/books[books] available for purchase +* Karl Seguin's online book: http://openmymind.net/mongodb.pdf[The Little MongoDB Book] diff --git a/src/main/asciidoc/introduction/requirements.adoc b/src/main/asciidoc/introduction/requirements.adoc new file mode 100644 index 000000000..b63b3e501 --- /dev/null +++ b/src/main/asciidoc/introduction/requirements.adoc @@ -0,0 +1,6 @@ +[[requirements]] += Requirements + +Spring Data MongoDB 1.x binaries requires JDK level 6.0 and above, and http://spring.io/docs[Spring Framework] 3.2.x and above. + +In terms of document stores, http://www.mongodb.org/[MongoDB] preferably version 2.4. diff --git a/src/main/asciidoc/preface.adoc b/src/main/asciidoc/preface.adoc new file mode 100644 index 000000000..a7639a7d1 --- /dev/null +++ b/src/main/asciidoc/preface.adoc @@ -0,0 +1,5 @@ +[[preface]] +[preface] += Preface + +The Spring Data MongoDB project applies core Spring concepts to the development of solutions using the MongoDB document style data store. We provide a "template" as a high-level abstraction for storing and querying documents. You will notice similarities to the JDBC support in the Spring Framework. diff --git a/src/main/asciidoc/reference/cross-store.adoc b/src/main/asciidoc/reference/cross-store.adoc new file mode 100644 index 000000000..32a8d8ecd --- /dev/null +++ b/src/main/asciidoc/reference/cross-store.adoc @@ -0,0 +1,243 @@ +[[mongo.cross.store]] += Cross Store support + +Sometimes you need to store data in multiple data stores and these data stores can be of different types. One might be relational while the other a document store. For this use case we have created a separate module in the MongoDB support that handles what we call cross-store support. The current implementation is based on JPA as the driver for the relational database and we allow select fields in the Entities to be stored in a Mongo database. In addition to allowing you to store your data in two stores we also coordinate persistence operations for the non-transactional MongoDB store with the transaction life-cycle for the relational database. + +[[mongodb_cross-store-configuration]] +== Cross Store Configuration + +Assuming that you have a working JPA application and would like to add some cross-store persistence for MongoDB. What do you have to add to your configuration? + +First of all you need to add a dependency on the module. Using Maven this is done by adding a dependency to your pom: + +=== Example Maven pom.xml with spring-data-mongodb-cross-store dependency + +[source,xml] +---- + + 4.0.0 + + ... + + + + org.springframework.data + spring-data-mongodb-cross-store + ${spring.data.mongo.version} + + + ... + + +---- + +Once this is done we need to enable AspectJ for the project. The cross-store support is implemented using AspectJ aspects so by enabling compile time AspectJ support the cross-store features will become available to your project. In Maven you would add an additional plugin to the section of the pom: + +=== Example Maven pom.xml with AspectJ plugin enabled + +[source,xml] +---- + + 4.0.0 + + ... + + + + + … + + + org.codehaus.mojo + aspectj-maven-plugin + 1.0 + + + + org.aspectj + aspectjrt + ${aspectj.version} + + + org.aspectj + aspectjtools + ${aspectj.version} + + + + + + compile + test-compile + + + + + true + + + org.springframework + spring-aspects + + + org.springframework.data + spring-data-mongodb-cross-store + + + 1.6 + 1.6 + + + + ... + + + + +... + + +---- + +Finally, you need to configure your project to use MongoDB and also configure the aspects that are used. The following XML snippet should be added to your application context: + +=== Example application context with MongoDB and cross-store aspect support + +[source,xml] +---- + + + + ... + + + + + + + + + + + + + + + + + + + + + + ... + + +---- + +[[mongodb_cross-store-application]] +== Writing the Cross Store Application + +We are assuming that you have a working JPA application so we will only cover the additional steps needed to persist part of your Entity in your Mongo database. First you need to identify the field you want persisted. It should be a domain class and follow the general rules for the Mongo mapping support covered in previous chapters. The field you want persisted in MongoDB should be annotated using the `@RelatedDocument` annotation. That is really all you need to do!. The cross-store aspects take care of the rest. This includes marking the field with `@Transient` so it won't be persisted using JPA, keeping track of any changes made to the field value and writing them to the database on successful transaction completion, loading the document from MongoDB the first time the value is used in your application. Here is an example of a simple Entity that has a field annotated with `@RelatedEntity`. + +=== Example of Entity with @RelatedDocument + +[source,java] +---- +@Entity +public class Customer { + + @Id + @GeneratedValue(strategy = GenerationType.IDENTITY) + private Long id; + + private String firstName; + + private String lastName; + + @RelatedDocument + private SurveyInfo surveyInfo; + + // getters and setters omitted +} +---- + +=== Example of domain class to be stored as document + +[source,java] +---- +public class SurveyInfo { + + private Map questionsAndAnswers; + + public SurveyInfo() { + this.questionsAndAnswers = new HashMap(); + } + + public SurveyInfo(Map questionsAndAnswers) { + this.questionsAndAnswers = questionsAndAnswers; + } + + public Map getQuestionsAndAnswers() { + return questionsAndAnswers; + } + + public void setQuestionsAndAnswers(Map questionsAndAnswers) { + this.questionsAndAnswers = questionsAndAnswers; + } + + public SurveyInfo addQuestionAndAnswer(String question, String answer) { + this.questionsAndAnswers.put(question, answer); + return this; + } +} +---- + +Once the SurveyInfo has been set on the Customer object above the MongoTemplate that was configured above is used to save the SurveyInfo along with some metadata about the JPA Entity is stored in a MongoDB collection named after the fully qualified name of the JPA Entity class. The following code: + +=== Example of code using the JPA Entity configured for cross-store persistence + +[source,java] +---- +Customer customer = new Customer(); +customer.setFirstName("Sven"); +customer.setLastName("Olafsen"); +SurveyInfo surveyInfo = new SurveyInfo() + .addQuestionAndAnswer("age", "22") + .addQuestionAndAnswer("married", "Yes") + .addQuestionAndAnswer("citizenship", "Norwegian"); +customer.setSurveyInfo(surveyInfo); +customerRepository.save(customer); +---- + +Executing the code above results in the following JSON document stored in MongoDB. + +=== Example of JSON document stored in MongoDB + +[source,javascript] +---- +{ "_id" : ObjectId( "4d9e8b6e3c55287f87d4b79e" ), + "_entity_id" : 1, + "_entity_class" : "org.springframework.data.mongodb.examples.custsvc.domain.Customer", + "_entity_field_name" : "surveyInfo", + "questionsAndAnswers" : { "married" : "Yes", + "age" : "22", + "citizenship" : "Norwegian" }, + "_entity_field_class" : "org.springframework.data.mongodb.examples.custsvc.domain.SurveyInfo" } +---- diff --git a/src/main/asciidoc/reference/introduction.adoc b/src/main/asciidoc/reference/introduction.adoc new file mode 100644 index 000000000..dff5a2e95 --- /dev/null +++ b/src/main/asciidoc/reference/introduction.adoc @@ -0,0 +1,10 @@ +[[introduction]] += Introduction + +== Document Structure + +This part of the reference documentation explains the core functionality offered by Spring Data Document. + +<> introduces the MongoDB module feature set. + +<> introduces the repository support for MongoDB. diff --git a/src/docbkx/reference/jconsole.png b/src/main/asciidoc/reference/jconsole.png similarity index 100% rename from src/docbkx/reference/jconsole.png rename to src/main/asciidoc/reference/jconsole.png diff --git a/src/main/asciidoc/reference/jmx.adoc b/src/main/asciidoc/reference/jmx.adoc new file mode 100644 index 000000000..7539120e3 --- /dev/null +++ b/src/main/asciidoc/reference/jmx.adoc @@ -0,0 +1,63 @@ +[[mongo.jmx]] += JMX support + +The JMX support for MongoDB exposes the results of executing the 'serverStatus' command on the admin database for a single MongoDB server instance. It also exposes an administrative MBean, MongoAdmin which will let you perform administrative operations such as drop or create a database. The JMX features build upon the JMX feature set available in the Spring Framework. See http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/jmx.html[here ] for more details. + +[[mongodb:jmx-configuration]] +== MongoDB JMX Configuration + +Spring's Mongo namespace enables you to easily enable JMX functionality + +=== XML schema to configure MongoDB + +[source,xml] +---- + + + + + + + + + + + + + + + + + + + + +---- + +This will expose several MBeans + +* AssertMetrics +* BackgroundFlushingMetrics +* BtreeIndexCounters +* ConnectionMetrics +* GlobalLoclMetrics +* MemoryMetrics +* OperationCounters +* ServerInfo +* MongoAdmin + +This is shown below in a screenshot from JConsole + +image::jconsole.png[] \ No newline at end of file diff --git a/src/main/asciidoc/reference/logging.adoc b/src/main/asciidoc/reference/logging.adoc new file mode 100644 index 000000000..5cd3c5d40 --- /dev/null +++ b/src/main/asciidoc/reference/logging.adoc @@ -0,0 +1,33 @@ +[[mongo.logging]] += Logging support + +An appender for Log4j is provided in the maven module "spring-data-mongodb-log4j". Note, there is no dependency on other Spring Mongo modules, only the MongoDB driver. + +[[mongodb:logging-configuration]] +== MongoDB Log4j Configuration + +Here is an example configuration + +[source] +---- +log4j.rootCategory=INFO, stdout + +log4j.appender.stdout=org.springframework.data.document.mongodb.log4j.MongoLog4jAppender +log4j.appender.stdout.layout=org.apache.log4j.PatternLayout +log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - <%m>%n +log4j.appender.stdout.host = localhost +log4j.appender.stdout.port = 27017 +log4j.appender.stdout.database = logs +log4j.appender.stdout.collectionPattern = %X{year}%X{month} +log4j.appender.stdout.applicationId = my.application +log4j.appender.stdout.warnOrHigherWriteConcern = FSYNC_SAFE + +log4j.category.org.apache.activemq=ERROR +log4j.category.org.springframework.batch=DEBUG +log4j.category.org.springframework.data.document.mongodb=DEBUG +log4j.category.org.springframework.transaction=INFO +---- + +The important configuration to look at aside from host and port is the database and collectionPattern. The variables year, month, day and hour are available for you to use in forming a collection name. This is to support the common convention of grouping log information in a collection that corresponds to a specific time period, for example a collection per day. + +There is also an applicationId which is put into the stored message. The document stored from logging as the following keys: level, name, applicationId, timestamp, properties, traceback, and message. diff --git a/src/main/asciidoc/reference/mapping.adoc b/src/main/asciidoc/reference/mapping.adoc new file mode 100644 index 000000000..8ac0314c4 --- /dev/null +++ b/src/main/asciidoc/reference/mapping.adoc @@ -0,0 +1,425 @@ +[[mapping-chapter]] += Mapping + +Rich mapping support is provided by the `MongoMappingConverter`. `MongoMappingConverter` has a rich metadata model that provides a full feature set of functionality to map domain objects to MongoDB documents.The mapping metadata model is populated using annotations on your domain objects. However, the infrastructure is not limited to using annotations as the only source of metadata information. The `MongoMappingConverter` also allows you to map objects to documents without providing any additional metadata, by following a set of conventions. + +In this section we will describe the features of the `MongoMappingConverter`. How to use conventions for mapping objects to documents and how to override those conventions with annotation based mapping metadata. + +NOTE: `SimpleMongoConverter` has been deprecated in Spring Data MongoDB M3 as all of its functionality has been subsumed into `MappingMongoConverter`. + +[[mapping-conventions]] +== Convention based Mapping + +`MongoMappingConverter` has a few conventions for mapping objects to documents when no additional mapping metadata is provided. The conventions are: + +* The short Java class name is mapped to the collection name in the following manner. The class '`com.bigbank.SavingsAccount`' maps to '`savingsAccount`' collection name. +* All nested objects are stored as nested objects in the document and *not* as DBRefs +* The converter will use any Spring Converters registered with it to override the default mapping of object properties to document field/values. +* The fields of an object are used to convert to and from fields in the document. Public JavaBean properties are not used. +* You can have a single non-zero argument constructor whose constructor argument names match top level field names of document, that constructor will be used. Otherwise the zero arg constructor will be used. if there is more than one non-zero argument constructor an exception will be thrown. + +[[mapping.conventions.id-field]] +=== How the '_id' field is handled in the mapping layer + +MongoDB requires that you have an '_id' field for all documents. If you don't provide one the driver will assign a ObjectId with a generated value. The "_id" field can be of any type the, other than arrays, so long as it is unique. The driver naturally supports all primitive types and Dates. When using the `MongoMappingConverter` there are certain rules that govern how properties from the Java class is mapped to this '_id' field. + +The following outlines what field will be mapped to the '_id' document field: + +* A field annotated with `@Id` (`org.springframework.data.annotation.Id`) will be mapped to the '_id' field. +* A field without an annotation but named `id` will be mapped to the '_id' field. + +The following outlines what type conversion, if any, will be done on the property mapped to the _id document field. + +* If a field named 'id' is declared as a String or BigInteger in the Java class it will be converted to and stored as an ObjectId if possible. ObjectId as a field type is also valid. If you specify a value for 'id' in your application, the conversion to an ObjectId is detected to the MongoDBdriver. If the specified 'id' value cannot be converted to an ObjectId, then the value will be stored as is in the document's _id field. +* If a field named ' id' id field is not declared as a String, BigInteger, or ObjectID in the Java class then you should assign it a value in your application so it can be stored 'as-is' in the document's _id field. +* If no field named 'id' is present in the Java class then an implicit '_id' file will be generated by the driver but not mapped to a property or field of the Java class. + +When querying and updating `MongoTemplate` will use the converter to handle conversions of the `Query` and `Update` objects that correspond to the above rules for saving documents so field names and types used in your queries will be able to match what is in your domain classes. + +[[mapping-configuration]] +== Mapping Configuration + +Unless explicitly configured, an instance of `MongoMappingConverter` is created by default when creating a `MongoTemplate`. You can create your own instance of the `MappingMongoConverter` so as to tell it where to scan the classpath at startup your domain classes in order to extract metadata and construct indexes. Also, by creating your own instance you can register Spring converters to use for mapping specific classes to and from the database. + +You can configure the `MongoMappingConverter` as well as `com.mongodb.Mongo` and MongoTemplate either using Java or XML based metadata. Here is an example using Spring's Java based configuration + +=== @Configuration class to configure MongoDB mapping support + +[source,java] +---- +@Configuration +public class GeoSpatialAppConfig extends AbstractMongoConfiguration { + + @Bean + public Mongo mongo() throws Exception { + return new Mongo("localhost"); + } + + @Override + public String getDatabaseName() { + return "database"; + } + + @Override + public String getMappingBasePackage() { + return "com.bigbank.domain"; + } + + // the following are optional + + + @Bean + @Override + public CustomConversions customConversions() throws Exception { + List> converterList = new ArrayList>(); + converterList.add(new org.springframework.data.mongodb.test.PersonReadConverter()); + converterList.add(new org.springframework.data.mongodb.test.PersonWriteConverter()); + return new CustomConversions(converterList); + } + + @Bean + public LoggingEventListener mappingEventsListener() { + return new LoggingEventListener(); + } +} +---- + +`AbstractMongoConfiguration` requires you to implement methods that define a `com.mongodb.Mongo` as well as provide a database name. `AbstractMongoConfiguration` also has a method you can override named '`getMappingBasePackage`' which tells the converter where to scan for classes annotated with the `@org.springframework.data.mongodb.core.mapping.Document` annotation. + +You can add additional converters to the converter by overriding the method afterMappingMongoConverterCreation. Also shown in the above example is a `LoggingEventListener` which logs `MongoMappingEvent`s that are posted onto Spring's `ApplicationContextEvent` infrastructure. + +NOTE: AbstractMongoConfiguration will create a MongoTemplate instance and registered with the container under the name 'mongoTemplate'. + +You can also override the method `UserCredentials getUserCredentials()` to provide the username and password information to connect to the database. + +Spring's MongoDB namespace enables you to easily enable mapping functionality in XML + +=== XML schema to configure MongoDB mapping support + +[source,xml] +---- + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +---- + +The `base-package` property tells it where to scan for classes annotated with the `@org.springframework.data.mongodb.core.mapping.Document` annotation. + +[[mapping-usage]] +== Metadata based Mapping + +To take full advantage of the object mapping functionality inside the Spring Data/MongoDB support, you should annotate your mapped objects with the `@org.springframework.data.mongodb.core.mapping.Document` annotation. Although it is not necessary for the mapping framework to have this annotation (your POJOs will be mapped correctly, even without any annotations), it allows the classpath scanner to find and pre-process your domain objects to extract the necessary metadata. If you don't use this annotation, your application will take a slight performance hit the first time you store a domain object because the mapping framework needs to build up its internal metadata model so it knows about the properties of your domain object and how to persist them. + +=== Example domain object + +[source,java] +---- +package com.mycompany.domain; + +@Document +public class Person { + + @Id + private ObjectId id; + + @Indexed + private Integer ssn; + + private String firstName; + + @Indexed + private String lastName; +} +---- + +The `@Id` annotation tells the mapper which property you want to use for the MongoDB `_id` property and the `@Indexed` annotation tells the mapping framework to call `ensureIndex` on that property of your document, making searches faster. + +Automatic index creation is only done for types annotated with `@Document`. + +[[mapping-usage-annotations]] +=== Mapping annotation overview + +The MappingMongoConverter can use metadata to drive the mapping of objects to documents. An overview of the annotations is provided below + +* `@Id `- applied at the field level to mark the field used for identiy purpose. +* `@Document` - applied at the class level to indicate this class is a candidate for mapping to the database. You can specify the name of the collection where the database will be stored. +* `@DBRef` - applied at the field to indicate it is to be stored using a com.mongodb.DBRef. +* `@Indexed` - applied at the field level to describe how to index the field. +* `@CompoundIndex` - applied at the type level to declare Compound Indexes +* `@GeoSpatialIndexed` - applied at the field level to describe how to geoindex the field. +* `@TextIndexed` - applied at the field level to mark the field to be included in the text index. +* `@Language` - applied at the field level to set the language override property for text index. +* `@Transient` - by default all private fields are mapped to the document, this annotation excludes the field where it is applied from being stored in the database +* `@PersistenceConstructor` - marks a given constructor - even a package protected one - to use when instantiating the object from the database. Constructor arguments are mapped by name to the key values in the retrieved DBObject. +* `@Value` - this annotation is part of the Spring Framework . Within the mapping framework it can be applied to constructor arguments. This lets you use a Spring Expression Language statement to transform a key's value retrieved in the database before it is used to construct a domain object. In order to reference a property of a given document one has to use expressions like: `@Value("#root.myProperty")` where `root` refers to the root of the given document. +* `@Field` - applied at the field level and described the name of the field as it will be represented in the MongoDB BSON document thus allowing the name to be different than the fieldname of the class. + +The mapping metadata infrastructure is defined in a seperate spring-data-commons project that is technology agnostic. Specific subclasses are using in the MongoDB support to support annotation based metadata. Other strategies are also possible to put in place if there is demand. + +Here is an example of a more complex mapping. + +[source,java] +---- +@Document +@CompoundIndexes({ + @CompoundIndex(name = "age_idx", def = "{'lastName': 1, 'age': -1}") +}) +public class Person { + + @Id + private String id; + + @Indexed(unique = true) + private Integer ssn; + + @Field("fName") + private String firstName; + + @Indexed + private String lastName; + + private Integer age; + + @Transient + private Integer accountTotal; + + @DBRef + private List accounts; + + private T address; + + + public Person(Integer ssn) { + this.ssn = ssn; + } + + @PersistenceConstructor + public Person(Integer ssn, String firstName, String lastName, Integer age, T address) { + this.ssn = ssn; + this.firstName = firstName; + this.lastName = lastName; + this.age = age; + this.address = address; + } + + public String getId() { + return id; + } + + // no setter for Id. (getter is only exposed for some unit testing) + + public Integer getSsn() { + return ssn; + } + +// other getters/setters ommitted +---- + +[[mapping-custom-object-construction]] +=== Customized Object Construction + +The mapping subsystem allows the customization of the object construction by annotating a constructor with the `@PersistenceConstructor` annotation. The values to be used for the constructor parameters are resolved in the following way: + +* If a parameter is annotated with the `@Value` annotation, the given expression is evaluated and the result is used as the parameter value. +* If the Java type has a property whose name matches the given field of the input document, then it's property information is used to select the appropriate constructor parameter to pass the input field value to. This works only if the parameter name information is present in the java `.class` files which can be achieved by compiling the source with debug information or using the new `-parameters` command-line switch for javac in Java 8. +* Otherwise an `MappingException` will be thrown indicating that the given constructor parameter could not be bound. + +[source,java] +---- +class OrderItem { + + private @Id String id; + private int quantity; + private double unitPrice; + + OrderItem(String id, @Value("#root.qty ?: 0") int quantity, double unitPrice) { + this.id = id; + this.quantity = quantity; + this.unitPrice = unitPrice; + } + + // getters/setters ommitted +} + +DBObject input = new BasicDBObject("id", "4711"); +input.put("unitPrice", 2.5); +input.put("qty",5); +OrderItem item = converter.read(OrderItem.class, input); +---- + +NOTE: The SpEL expression in the `@Value` annotation of the `quantity` parameter falls back to the value `0` if the given property path cannot be resolved. + +Additional examples for using the `@PersistenceConstructor` annotation can be found in the https://github.com/spring-projects/spring-data-mongodb/blob/master/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java[MappingMongoConverterUnitTests] test suite. + +[[mapping-usage-indexes.compound-index]] +=== Compound Indexes + +Compound indexes are also supported. They are defined at the class level, rather than on indidividual properties. + +NOTE: Compound indexes are very important to improve the performance of queries that involve criteria on multiple fields + +Here's an example that creates a compound index of `lastName` in ascending order and `age` in descending order: + +==== Example Compound Index Usage + +[source,java] +---- +package com.mycompany.domain; + +@Document +@CompoundIndexes({ + @CompoundIndex(name = "age_idx", def = "{'lastName': 1, 'age': -1}") +}) +public class Person { + + @Id + private ObjectId id; + private Integer age; + private String firstName; + private String lastName; + +} +---- + +[[mapping-usage-indexes.text-index]] +=== Text Indexes + +NOTE: The text index feature is disabled by default for mongodb v.2.4. + +Creating a text index allows to accumulate several fields into a searchable full text index. It is only possible to have one text index per collection so all fields marked with `@TextIndexed` are combined into this index. Properties can be weighted to influence document score for ranking results. The default language for the text index is english, to change the default language set `@Document(language="spanish")` to any language you want. Using a property called `language` or `@Language` allows to define a language override on a per document base. + +==== Example Text Index Usage + +[source,java] +---- +@Document(language = "spanish") +class SomeEntity { + + @TextIndexed String foo; + + @Language String lang; + + Nested nested; +} + +class Nested { + + @TextIndexed(weight=5) String bar; + String roo; +} +---- + +[[mapping-usage-references]] +=== Using DBRefs + +The mapping framework doesn't have to store child objects embedded within the document. You can also store them separately and use a DBRef to refer to that document. When the object is loaded from MongoDB, those references will be eagerly resolved and you will get back a mapped object that looks the same as if it had been stored embedded within your master document. + +Here's an example of using a DBRef to refer to a specific document that exists independently of the object in which it is referenced (both classes are shown in-line for brevity's sake): + +[source,java] +---- +@Document +public class Account { + + @Id + private ObjectId id; + private Float total; +} + +@Document +public class Person { + + @Id + private ObjectId id; + @Indexed + private Integer ssn; + @DBRef + private List accounts; +} +---- + +There's no need to use something like `@OneToMany` because the mapping framework sees that you're wanting a one-to-many relationship because there is a List of objects. When the object is stored in MongoDB, there will be a list of DBRefs rather than the `Account` objects themselves. + +The mapping framework does not handle cascading saves. If you change an `Account` object that is referenced by a `Person` object, you must save the Account object separately. Calling `save` on the `Person` object will not automatically save the `Account` objects in the property `accounts`. + +[[mapping-usage-events]] +=== Mapping Framework Events + +Events are fired throughout the lifecycle of the mapping process. This is described in the <> section. + +Simply declaring these beans in your Spring ApplicationContext will cause them to be invoked whenever the event is dispatched. + +[[mapping-explicit-converters]] +=== Overriding Mapping with explicit Converters + +When storing and querying your objects it is convenient to have a `MongoConverter` instance handle the mapping of all Java types to DBObjects. However, sometimes you may want the `MongoConverter`'s do most of the work but allow you to selectively handle the conversion for a particular type or to optimize performance. + +To selectively handle the conversion yourself, register one or more one or more `org.springframework.core.convert.converter.Converter` instances with the MongoConverter. + +NOTE: Spring 3.0 introduced a core.convert package that provides a general type conversion system. This is described in detail in the Spring reference documentation section entitled http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/validation.html#core-convert[Spring 3 Type Conversion]. + +The method `customConversions` in `AbstractMongoConfiguration` can be used to configure Converters. The examples <> at the beginning of this chapter show how to perform the configuration using Java and XML. + +Below is an example of a Spring Converter implementation that converts from a DBObject to a Person POJO. + +[source,java] +---- +@ReadingConverter + public class PersonReadConverter implements Converter { + + public Person convert(DBObject source) { + Person p = new Person((ObjectId) source.get("_id"), (String) source.get("name")); + p.setAge((Integer) source.get("age")); + return p; + } +} +---- + +Here is an example that converts from a Person to a DBObject. + +[source,java] +---- +@WritingConverter +public class PersonWriteConverter implements Converter { + + public DBObject convert(Person source) { + DBObject dbo = new BasicDBObject(); + dbo.put("_id", source.getId()); + dbo.put("name", source.getFirstName()); + dbo.put("age", source.getAge()); + return dbo; + } +} +---- diff --git a/src/main/asciidoc/reference/mongo-repositories.adoc b/src/main/asciidoc/reference/mongo-repositories.adoc new file mode 100644 index 000000000..e1189fd26 --- /dev/null +++ b/src/main/asciidoc/reference/mongo-repositories.adoc @@ -0,0 +1,334 @@ +[[mongo.repositories]] += MongoDB repositories + +[[mongo-repo-intro]] +== Introduction + +This chapter will point out the specialties for repository support for MongoDB. This builds on the core repository support explained in <>. So make sure you've got a sound understanding of the basic concepts explained there. + +[[mongo-repo-usage]] +== Usage + +To access domain entities stored in a MongoDB you can leverage our sophisticated repository support that eases implementing those quite significantly. To do so, simply create an interface for your repository: + +=== Sample Person entity + +[source,java] +---- +public class Person { + + @Id + private String id; + private String firstname; + private String lastname; + private Address address; + + // … getters and setters omitted +} +---- + +We have a quite simple domain object here. Note that it has a property named `id` of type`ObjectId`. The default serialization mechanism used in `MongoTemplate` (which is backing the repository support) regards properties named id as document id. Currently we support`String`, `ObjectId` and `BigInteger` as id-types. + +=== Basic repository interface to persist Person entities + +[source] +---- +public interface PersonRepository extends PagingAndSortingRepository { + + // additional custom finder methods go here +} +---- + +Right now this interface simply serves typing purposes but we will add additional methods to it later. In your Spring configuration simply add + +=== General MongoDB repository Spring configuration + +[source,xml] +---- + + + + + + + + + + + + + +---- + +This namespace element will cause the base packages to be scanned for interfaces extending `MongoRepository` and create Spring beans for each of them found. By default the repositories will get a `MongoTemplate` Spring bean wired that is called `mongoTemplate`, so you only need to configure `mongo-template-ref` explicitly if you deviate from this convention. + +If you'd rather like to go with JavaConfig use the `@EnableMongoRepositories` annotation. The annotation carries the very same attributes like the namespace element. If no base package is configured the infrastructure will scan the package of the annotated configuration class. + +=== JavaConfig for repositories + +[source,java] +---- +@Configuration +@EnableMongoRepositories +class ApplicationConfig extends AbstractMongoConfiguration { + + @Override + protected String getDatabaseName() { + return "e-store"; + } + + @Override + public Mongo mongo() throws Exception { + return new Mongo(); + } + + @Override + protected String getMappingBasePackage() { + return "com.oreilly.springdata.mongodb" + } +} +---- + +As our domain repository extends `PagingAndSortingRepository` it provides you with CRUD operations as well as methods for paginated and sorted access to the entities. Working with the repository instance is just a matter of dependency injecting it into a client. So accessing the second page of `Person`s at a page size of 10 would simply look something like this: + +=== Paging access to Person entities + +[source,java] +---- +@RunWith(SpringJUnit4ClassRunner.class) +@ContextConfiguration +public class PersonRepositoryTests { + + @Autowired PersonRepository repository; + + @Test + public void readsFirstPageCorrectly() { + + Page persons = repository.findAll(new PageRequest(0, 10)); + assertThat(persons.isFirstPage(), is(true)); + } +} +---- + +The sample creates an application context with Spring's unit test support which will perform annotation based dependency injection into test cases. Inside the test method we simply use the repository to query the datastore. We hand the repository a `PageRequest` instance that requests the first page of persons at a page size of 10. + +[[mongodb.repositories.queries]] +== Query methods + +Most of the data access operations you usually trigger on a repository result a query being executed against the MongoDB databases. Defining such a query is just a matter of declaring a method on the repository interface + +=== PersonRepository with query methods + +[source,java] +---- +public interface PersonRepository extends PagingAndSortingRepository { + + List findByLastname(String lastname); + + Page findByFirstname(String firstname, Pageable pageable); + + Person findByShippingAddresses(Address address); +} +---- + +The first method shows a query for all people with the given lastname. The query will be derived parsing the method name for constraints which can be concatenated with `And` and `Or`. Thus the method name will result in a query expression of`{"lastname" : lastname}`. The second example shows how pagination is applied to a query. Just equip your method signature with a `Pageable` parameter and let the method return a `Page` instance and we will automatically page the query accordingly. The third examples shows that you can query based on properties which are not a primitive type. + +NOTE: Note that for version 1.0 we currently don't support referring to parameters that are mapped as `DBRef` in the domain class. + +[[mongodb.repositories.queries.delete]] +=== Repository delete queries + +The above keywords can be used in conjunciton with `delete…By` or `remove…By` to create queries deleting matching documents. + +==== `Delete…By` Query + +[source,java] +---- +public interface PersonRepository extends MongoRepository { + + List deleteByLastname(String lastname); + + Long deletePersonByLastname(String lastname); +} +---- + +Using return type `List` will retrieve and return all matching documents before actually deleting them. A numeric return type directly removes the matching documents returning the total number of documents removed. + +[[mongodb.repositories.queries.geo-spatial]] +=== Geo-spatial repository queries + +As you've just seen there are a few keywords triggering geo-spatial operations within a MongoDB query. The `Near` keyword allows some further modification. Let's have look at some examples: + +==== Advanced `Near` queries + +[source,java] +---- +public interface PersonRepository extends MongoRepository + + // { 'location' : { '$near' : [point.x, point.y], '$maxDistance' : distance}} + List findByLocationNear(Point location, Distance distance); +} +---- + +Adding a `Distance` parameter to the query method allows restricting results to those within the given distance. If the `Distance` was set up containing a `Metric` we will transparently use `$nearSphere` instead of $code. + +==== Using `Distance` with `Metrics` + +[source,java] +---- +Point point = new Point(43.7, 48.8); +Distance distance = new Distance(200, Metrics.KILOMETERS); +… = repository.findByLocationNear(point, distance); +// {'location' : {'$nearSphere' : [43.7, 48.8], '$maxDistance' : 0.03135711885774796}} +---- + +As you can see using a `Distance` equipped with a `Metric` causes `$nearSphere` clause to be added instead of a plain `$near`. Beyond that the actual distance gets calculated according to the `Metrics` used. + +==== Geo-near queries + +[source,java] +---- +public interface PersonRepository extends MongoRepository + + // {'geoNear' : 'location', 'near' : [x, y] } + GeoResults findByLocationNear(Point location); + + // No metric: {'geoNear' : 'person', 'near' : [x, y], maxDistance : distance } + // Metric: {'geoNear' : 'person', 'near' : [x, y], 'maxDistance' : distance, + // 'distanceMultiplier' : metric.multiplier, 'spherical' : true } + GeoResults findByLocationNear(Point location, Distance distance); + + // {'geoNear' : 'location', 'near' : [x, y] } + GeoResults findByLocationNear(Point location); +} +---- + +[[mongodb.repositories.queries.json-based]] +=== MongoDB JSON based query methods and field restriction + +By adding the annotation `org.springframework.data.mongodb.repository.Query` repository finder methods you can specify a MongoDB JSON query string to use instead of having the query derived from the method name. For example + +[source,java] +---- +public interface PersonRepository extends MongoRepository + + @Query("{ 'firstname' : ?0 }") + List findByThePersonsFirstname(String firstname); + +} +---- + +The placeholder ?0 lets you substitute the value from the method arguments into the JSON query string. + +You can also use the filter property to restrict the set of properties that will be mapped into the Java object. For example, + +[source,java] +---- +public interface PersonRepository extends MongoRepository + + @Query(value="{ 'firstname' : ?0 }", fields="{ 'firstname' : 1, 'lastname' : 1}") + List findByThePersonsFirstname(String firstname); + +} +---- + +This will return only the firstname, lastname and Id properties of the Person objects. The age property, a java.lang.Integer, will not be set and its value will therefore be null. + +[[mongodb.repositories.queries.type-safe]] +=== Type-safe Query methods + +MongoDB repository support integrates with the http://www.querydsl.com/[QueryDSL] project which provides a means to perform type-safe queries in Java. To quote from the project description, "Instead of writing queries as inline strings or externalizing them into XML files they are constructed via a fluent API." It provides the following features + +* Code completion in IDE (all properties, methods and operations can be expanded in your favorite Java IDE) +* Almost no syntactically invalid queries allowed (type-safe on all levels) +* Domain types and properties can be referenced safely (no Strings involved!) +* Adopts better to refactoring changes in domain types +* Incremental query definition is easier + +Please refer to the QueryDSL documentation which describes how to bootstrap your environment for APT based code generation http://source.mysema.com/static/querydsl/2.1.2/reference/html/ch02.html#d0e112[using Maven] or http://source.mysema.com/static/querydsl/2.1.2/reference/html/ch02.html#d0e131[using Ant]. + +Using QueryDSL you will be able to write queries as shown below + +[source,java] +---- +QPerson person = new QPerson("person"); +List result = repository.findAll(person.address.zipCode.eq("C0123")); + +Page page = repository.findAll(person.lastname.contains("a"), + new PageRequest(0, 2, Direction.ASC, "lastname")); +---- + +`QPerson` is a class that is generated (via the Java annotation post processing tool) which is a `Predicate` that allows you to write type safe queries. Notice that there are no strings in the query other than the value "C0123". + +You can use the generated `Predicate` class via the interface `QueryDslPredicateExecutor` which is shown below + +[source,java] +---- +public interface QueryDslPredicateExecutor { + + T findOne(Predicate predicate); + + List findAll(Predicate predicate); + + List findAll(Predicate predicate, OrderSpecifier... orders); + + Page findAll(Predicate predicate, Pageable pageable); + + Long count(Predicate predicate); +} +---- + +To use this in your repository implementation, simply inherit from it in addition to other repository interfaces. This is shown below + +[source,java] +---- +public interface PersonRepository extends MongoRepository, QueryDslPredicateExecutor { + + // additional finder methods go here +} +---- + +We think you will find this an extremely powerful tool for writing MongoDB queries. + +[[mongodb.repositories.misc]] +== Miscellaneous + +[[mongodb.repositories.misc.cdi-integration]] +=== CDI Integration + +Instances of the repository interfaces are usually created by a container, which Spring is the most natural choice when working with Spring Data. As of version 1.3.0 Spring Data MongoDB ships with a custom CDI extension that allows using the repository abstraction in CDI environments. The extension is part of the JAR so all you need to do to activate it is dropping the Spring Data MongoDB JAR into your classpath. You can now set up the infrastructure by implementing a CDI Producer for the `MongoTemplate`: + +[source,java] +---- +class MongoTemplateProducer { + + @Produces + @ApplicationScoped + public MongoOperations createMongoTemplate() throws UnknownHostException, MongoException { + + MongoDbFactory factory = new SimpleMongoDbFactory(new Mongo(), "database"); + return new MongoTemplate(factory); + } +} +---- + +The Spring Data MongoDB CDI extension will pick up the `MongoTemplate` available as CDI bean and create a proxy for a Spring Data repository whenever an bean of a repository type is requested by the container. Thus obtaining an instance of a Spring Data repository is a matter of declaring an `@Inject`-ed property: + +[source,java] +---- +class RepositoryClient { + + @Inject + PersonRepository repository; + + public void businessMethod() { + List people = repository.findAll(); + } +} +---- \ No newline at end of file diff --git a/src/main/asciidoc/reference/mongodb.adoc b/src/main/asciidoc/reference/mongodb.adoc new file mode 100644 index 000000000..77e6ec549 --- /dev/null +++ b/src/main/asciidoc/reference/mongodb.adoc @@ -0,0 +1,2198 @@ +[[mongo.core]] += MongoDB support + +The MongoDB support contains a wide range of features which are summarized below. + +* Spring configuration support using Java based @Configuration classes or an XML namespace for a Mongo driver instance and replica sets +* MongoTemplate helper class that increases productivity performing common Mongo operations. Includes integrated object mapping between documents and POJOs. +* Exception translation into Spring's portable Data Access Exception hierarchy +* Feature Rich Object Mapping integrated with Spring's Conversion Service +* Annotation based mapping metadata but extensible to support other metadata formats +* Persistence and mapping lifecycle events +* Java based Query, Criteria, and Update DSLs +* Automatic implementation of Repository interfaces including support for custom finder methods. +* QueryDSL integration to support type-safe queries. +* Cross-store persistance - support for JPA Entities with fields transparently persisted/retrieved using MongoDB +* Log4j log appender +* GeoSpatial integration + +For most tasks you will find yourself using `MongoTemplate` or the Repository support that both leverage the rich mapping functionality. MongoTemplate is the place to look for accessing functionality such as incrementing counters or ad-hoc CRUD operations. MongoTemplate also provides callback methods so that it is easy for you to get a hold of the low level API artifacts such as `org.mongo.DB` to communicate directly with MongoDB. The goal with naming conventions on various API artifacts is to copy those in the base MongoDB Java driver so you can easily map your existing knowledge onto the Spring APIs. + +[[mongodb-getting-started]] +== Getting Started + +Spring MongoDB support requires MongoDB 1.4 or higher and Java SE 5 or higher. The latest production release (2.4.9 as of this writing) is recommended. An easy way to bootstrap setting up a working environment is to create a Spring based project in http://spring.io/tools/sts[STS]. + +First you need to set up a running Mongodb server. Refer to the http://docs.mongodb.org/manual/core/introduction/[Mongodb Quick Start guide] for an explanation on how to startup a MongoDB instance. Once installed starting MongoDB is typically a matter of executing the following command: `MONGO_HOME/bin/mongod` + +To create a Spring project in STS go to File -> New -> Spring Template Project -> Simple Spring Utility Project -> press Yes when prompted. Then enter a project and a package name such as org.spring.mongodb.example. + +Then add the following to pom.xml dependencies section. + +[source,xml] +---- + + + + + + org.springframework.data + spring-data-mongodb + 1.4.1.RELEASE + + + +---- + +Also change the version of Spring in the pom.xml to be + +[source,xml] +---- +3.2.8.RELEASE +---- + +You will also need to add the location of the Spring Milestone repository for maven to your pom.xml which is at the same level of your element + +[source,xml] +---- + + + spring-milestone + Spring Maven MILESTONE Repository + http://repo.spring.io/libs-milestone + + +---- + +The repository is also http://shrub.appspot.com/maven.springframework.org/milestone/org/springframework/data/[browseable here]. + +You may also want to set the logging level to `DEBUG` to see some additional information, edit the log4j.properties file to have + +[source] +---- +log4j.category.org.springframework.data.document.mongodb=DEBUG +log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %40.40c:%4L - %m%n +---- + +Create a simple Person class to persist: + +[source,java] +---- +package org.spring.mongodb.example; + +public class Person { + + private String id; + private String name; + private int age; + + public Person(String name, int age) { + this.name = name; + this.age = age; + } + + public String getId() { + return id; + } + public String getName() { + return name; + } + public int getAge() { + return age; + } + + @Override + public String toString() { + return "Person [id=" + id + ", name=" + name + ", age=" + age + "]"; + } +} +---- + +And a main application to run + +[source,java] +---- +package org.spring.mongodb.example; + +import static org.springframework.data.mongodb.core.query.Criteria.where; + +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; +import org.springframework.data.mongodb.core.MongoOperations; +import org.springframework.data.mongodb.core.MongoTemplate; +import org.springframework.data.mongodb.core.query.Query; + +import com.mongodb.Mongo; + +public class MongoApp { + + private static final Log log = LogFactory.getLog(MongoApp.class); + + public static void main(String[] args) throws Exception { + + MongoOperations mongoOps = new MongoTemplate(new Mongo(), "database"); + mongoOps.insert(new Person("Joe", 34)); + + log.info(mongoOps.findOne(new Query(where("name").is("Joe")), Person.class)); + + mongoOps.dropCollection("person"); + } +} +---- + +This will produce the following output + +[source] +---- +10:01:32,062 DEBUG apping.MongoPersistentEntityIndexCreator: 80 - Analyzing class class org.spring.example.Person for index information. +10:01:32,265 DEBUG ramework.data.mongodb.core.MongoTemplate: 631 - insert DBObject containing fields: [_class, age, name] in collection: Person +10:01:32,765 DEBUG ramework.data.mongodb.core.MongoTemplate:1243 - findOne using query: { "name" : "Joe"} in db.collection: database.Person +10:01:32,953 INFO org.spring.mongodb.example.MongoApp: 25 - Person [id=4ddbba3c0be56b7e1b210166, name=Joe, age=34] +10:01:32,984 DEBUG ramework.data.mongodb.core.MongoTemplate: 375 - Dropped collection [database.person] +---- + +Even in this simple example, there are few things to take notice of + +* You can instantiate the central helper class of Spring Mongo, <>, using the standard `com.mongodb.Mongo` object and the name of the database to use. +* The mapper works against standard POJO objects without the need for any additional metadata (though you can optionally provide that information. See <>.). +* Conventions are used for handling the id field, converting it to be a ObjectId when stored in the database. +* Mapping conventions can use field access. Notice the Person class has only getters. +* If the constructor argument names match the field names of the stored document, they will be used to instantiate the object + +[[mongo.examples-repo]] +== Examples Repository + +There is an https://github.com/spring-projects/spring-data-document-examples[github repository with several examples] that you can download and play around with to get a feel for how the library works. + +[[mongodb-connectors]] +== Connecting to MongoDB with Spring + +One of the first tasks when using MongoDB and Spring is to create a `com.mongodb.Mongo` object using the IoC container. There are two main ways to do this, either using Java based bean metadata or XML based bean metadata. These are discussed in the following sections. + +NOTE: For those not familiar with how to configure the Spring container using Java based bean metadata instead of XML based metadata see the high level introduction in the reference docs http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/new-in-3.0.html#new-java-configuration[here ] as well as the detailed documentationhttp://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/beans.html#beans-java-instantiating-container[ here]. + +[[mongo.mongo-java-config]] +=== Registering a Mongo instance using Java based metadata + +An example of using Java based bean metadata to register an instance of a `com.mongodb.Mongo` is shown below + +==== Registering a com.mongodb.Mongo object using Java based bean metadata + +[source,java] +---- +@Configuration +public class AppConfig { + + /* + * Use the standard Mongo driver API to create a com.mongodb.Mongo instance. + */ + public @Bean Mongo mongo() throws UnknownHostException { + return new Mongo("localhost"); + } +} +---- + +This approach allows you to use the standard `com.mongodb.Mongo` API that you may already be used to using but also pollutes the code with the UnknownHostException checked exception. The use of the checked exception is not desirable as Java based bean metadata uses methods as a means to set object dependencies, making the calling code cluttered. + +An alternative is to register an instance of `com.mongodb.Mongo` instance with the container using Spring's` MongoFactoryBean`. As compared to instantiating a `com.mongodb.Mongo` instance directly, the FactoryBean approach does not throw a checked exception and has the added advantage of also providing the container with an ExceptionTranslator implementation that translates MongoDB exceptions to exceptions in Spring's portable `DataAccessException` hierarchy for data access classes annoated with the `@Repository` annotation. This hierarchy and use of `@Repository` is described in http://docs.spring.io/spring/docs/current/spring-framework-reference/html/dao.html[Spring's DAO support features]. + +An example of a Java based bean metadata that supports exception translation on `@Repository` annotated classes is shown below: + +==== Registering a com.mongodb.Mongo object using Spring's MongoFactoryBean and enabling Spring's exception translation support + +[source,java] +---- +@Configuration +public class AppConfig { + + /* + * Factory bean that creates the com.mongodb.Mongo instance + */ + public @Bean MongoFactoryBean mongo() { + MongoFactoryBean mongo = new MongoFactoryBean(); + mongo.setHost("localhost"); + return mongo; + } +} +---- + +To access the `com.mongodb.Mongo` object created by the `MongoFactoryBean` in other `@Configuration` or your own classes, use a "`private @Autowired Mongo mongo;`" field. + +[[mongo.mongo-xml-config]] +=== Registering a Mongo instance using XML based metadata + +While you can use Spring's traditional `` XML namespace to register an instance of `com.mongodb.Mongo` with the container, the XML can be quite verbose as it is general purpose. XML namespaces are a better alternative to configuring commonly used objects such as the Mongo instance. The mongo namespace alows you to create a Mongo instance server location, replica-sets, and options. + +To use the Mongo namespace elements you will need to reference the Mongo schema: + +==== XML schema to configure MongoDB + +[source,xml] +---- + + + + + ** + + +---- + +A more advanced configuration with MongoOptions is shown below (note these are not recommended values) + +==== XML schema to configure a com.mongodb.Mongo object with MongoOptions + +[source,xml] +---- + + + + + + + + +---- + +A configuration using replica sets is shown below. + +===== XML schema to configure com.mongodb.Mongo object with Replica Sets + +[source,xml] +---- + +---- + +[[mongo.mongo-db-factory]] +=== The MongoDbFactory interface + +While `com.mongodb.Mongo` is the entry point to the MongoDB driver API, connecting to a specific MongoDB database instance requires additional information such as the database name and an optional username and password. With that information you can obtain a com.mongodb.DB object and access all the functionality of a specific MongoDB database instance. Spring provides the `org.springframework.data.mongodb.core.MongoDbFactory` interface shown below to bootstrap connectivity to the database. + +[source,java] +---- +public interface MongoDbFactory { + + DB getDb() throws DataAccessException; + + DB getDb(String dbName) throws DataAccessException; +} +---- + +The following sections show how you can use the container with either Java or the XML based metadata to configure an instance of the `MongoDbFactory` interface. In turn, you can use the `MongoDbFactory` instance to configure MongoTemplate. + +The class `org.springframework.data.mongodb.core.SimpleMongoDbFactory` provides implements the MongoDbFactory interface and is created with a standard `com.mongodb.Mongo` instance, the database name and an optional `org.springframework.data.authentication.UserCredentials` constructor argument. + +Instead of using the IoC container to create an instance of MongoTemplate, you can just use them in standard Java code as shown below. + +[source,java] +---- +public class MongoApp { + + private static final Log log = LogFactory.getLog(MongoApp.class); + + public static void main(String[] args) throws Exception { + + MongoOperations mongoOps = new MongoTemplate(*new SimpleMongoDbFactory(new Mongo(), "database")*); + + mongoOps.insert(new Person("Joe", 34)); + + log.info(mongoOps.findOne(new Query(where("name").is("Joe")), Person.class)); + + mongoOps.dropCollection("person"); + } +} +---- + +The code in bold highlights the use of SimpleMongoDbFactory and is the only difference between the listing shown in the <>. + +[[mongo.mongo-db-factory-java]] +=== Registering a MongoDbFactory instance using Java based metadata + +To register a MongoDbFactory instance with the container, you write code much like what was highlighted in the previous code listing. A simple example is shown below + +[source,java] +---- +@Configuration +public class MongoConfiguration { + + public @Bean MongoDbFactory mongoDbFactory() throws Exception { + return new SimpleMongoDbFactory(new Mongo(), "database"); + } +} +---- + +To define the username and password create an instance of `org.springframework.data.authentication.UserCredentials` and pass it into the constructor as shown below. This listing also shows using `MongoDbFactory` register an instance of MongoTemplate with the container. + +[source,java] +---- +@Configuration +public class MongoConfiguration { + + public @Bean MongoDbFactory mongoDbFactory() throws Exception { + UserCredentials userCredentials = new UserCredentials("joe", "secret"); + return new SimpleMongoDbFactory(new Mongo(), "database", userCredentials); + } + + public @Bean MongoTemplate mongoTemplate() throws Exception { + return new MongoTemplate(mongoDbFactory()); + } +} +---- + + +[[mongo.mongo-db-factory-xml]] +=== Registering a MongoDbFactory instance using XML based metadata + +The mongo namespace provides a convient way to create a `SimpleMongoDbFactory` as compared to using the`` namespace. Simple usage is shown below + +[source,xml] +---- + +---- + +In the above example a `com.mongodb.Mongo` instance is created using the default host and port number. The `SimpleMongoDbFactory` registered with the container is identified by the id 'mongoDbFactory' unless a value for the id attribute is specified. + +You can also provide the host and port for the underlying `com.mongodb.Mongo` instance as shown below, in addition to username and password for the database. + +[source,xml] +---- + +---- + +If you need to configure additional options on the `com.mongodb.Mongo` instance that is used to create a `SimpleMongoDbFactory` you can refer to an existing bean using the `mongo-ref` attribute as shown below. To show another common usage pattern, this listing show the use of a property placeholder to parameterise the configuration and creating `MongoTemplate`. + +[source,xml] +---- + + + + + + + + + + + +---- + +[[mongo.auditing]] +== General auditing configuration + +Activating auditing functionality is just a matter of adding the Spring Data Mongo `auditing` namespace element to your configuration: + +=== Activating auditing using XML configuration + +[source,xml] +---- + +---- + +Since Spring Data MongoDB 1.4 auditing can be enabled by annotating a configuration class with the `@EnableMongoAuditing` annotation. + +=== Activating auditing using JavaConfig + +[source,java] +---- +@Configuration +@EnableMongoAuditing +class Config { + + @Bean + public AuditorAware myAuditorProvider() { + return new AuditorAwareImpl(); + } +} +---- + +If you expose a bean of type `AuditorAware` to the `ApplicationContext`, the auditing infrastructure will pick it up automatically and use it to determine the current user to be set on domain types. If you have multiple implementations registered in the `ApplicationContext`, you can select the one to be used by explicitly setting the `auditorAwareRef` attribute of `@EnableJpaAuditing`. + +[[mongo-template]] +== Introduction to MongoTemplate + +The class `MongoTemplate`, located in the package `org.springframework.data.document.mongodb`, is the central class of the Spring's MongoDB support providing a rich feature set to interact with the database. The template offers convenience operations to create, update, delete and query for MongoDB documents and provides a mapping between your domain objects and MongoDB documents. + +NOTE: Once configured, `MongoTemplate` is thread-safe and can be reused across multiple instances. + +The mapping between MongoDB documents and domain classes is done by delegating to an implementation of the interface `MongoConverter`. Spring provides two implementations, `SimpleMappingConverter` and `MongoMappingConverter`, but you can also write your own converter. Please refer to the section on MongoConverters for more detailed information. + +The `MongoTemplate` class implements the interface `MongoOperations`. In as much as possible, the methods on `MongoOperations` are named after methods available on the MongoDB driver `Collection` object as as to make the API familiar to existing MongoDB developers who are used to the driver API. For example, you will find methods such as "find", "findAndModify", "findOne", "insert", "remove", "save", "update" and "updateMulti". The design goal was to make it as easy as possible to transition between the use of the base MongoDB driver and `MongoOperations`. A major difference in between the two APIs is that MongoOperations can be passed domain objects instead of `DBObject` and there are fluent APIs for `Query`, `Criteria`, and `Update` operations instead of populating a `DBObject` to specify the parameters for those operations. + +NOTE: The preferred way to reference the operations on `MongoTemplate` instance is via its interface `MongoOperations`. + +The default converter implementation used by `MongoTemplate` is MongoMappingConverter. While the `MongoMappingConverter` can make use of additional metadata to specify the mapping of objects to documents it is also capable of converting objects that contain no additional metadata by using some conventions for the mapping of IDs and collection names. These conventions as well as the use of mapping annotations is explained in the <>. + +NOTE: In the M2 release `SimpleMappingConverter`, was the default and this class is now deprecated as its functionality has been subsumed by the MongoMappingConverter. + +Another central feature of MongoTemplate is exception translation of exceptions thrown in the MongoDB Java driver into Spring's portable Data Access Exception hierarchy. Refer to the section on <> for more information. + +While there are many convenience methods on `MongoTemplate` to help you easily perform common tasks if you should need to access the MongoDB driver API directly to access functionality not explicitly exposed by the MongoTemplate you can use one of several Execute callback methods to access underlying driver APIs. The execute callbacks will give you a reference to either a `com.mongodb.Collection` or a `com.mongodb.DB` object. Please see the section mongo.executioncallback[Execution Callbacks] for more information. + +Now let's look at a examples of how to work with the `MongoTemplate` in the context of the Spring container. + +[[mongo-template.instantiating]] +=== Instantiating MongoTemplate + +You can use Java to create and register an instance of MongoTemplate as shown below. + +==== Registering a com.mongodb.Mongo object and enabling Spring's exception translation support + +[source,java] +---- +@Configuration +public class AppConfig { + + public @Bean Mongo mongo() throws Exception { + return new Mongo("localhost"); + } + + public @Bean MongoTemplate mongoTemplate() throws Exception { + return new MongoTemplate(mongo(), "mydatabase"); + } +} +---- + +There are several overloaded constructors of MongoTemplate. These are + +* `MongoTemplate(Mongo mongo, String databaseName)` - takes the `com.mongodb.Mongo` object and the default database name to operate against. +* `MongoTemplate(Mongo mongo, String databaseName, UserCredentials userCredentials)` - adds the username and password for authenticating with the database. +* `MongoTemplate(MongoDbFactory mongoDbFactory)` - takes a MongoDbFactory object that encapsulated the `com.mongodb.Mongo` object, database name, and username and password. +* `MongoTemplate(MongoDbFactory mongoDbFactory, MongoConverter mongoConverter)` - adds a MongoConverter to use for mapping. + +You can also configure a MongoTemplate using Spring's XML schema. + +[source,java] +---- + + + + + + +---- + +Other optional properties that you might like to set when creating a `MongoTemplate` are the default `WriteResultCheckingPolicy`, `WriteConcern`, and `ReadPreference`. + +NOTE: The preferred way to reference the operations on `MongoTemplate` instance is via its interface `MongoOperations`. + +[[mongo-template.writeresultchecking]] +=== WriteResultChecking Policy + +When in development it is very handy to either log or throw an exception if the `com.mongodb.WriteResult` returned from any MongoDB operation contains an error. It is quite common to forget to do this during development and then end up with an application that looks like it runs successfully but in fact the database was not modified according to your expectations. Set MongoTemplate's property to an enum with the following values, LOG, EXCEPTION, or NONE to either log the error, throw and exception or do nothing. The default is to use a `WriteResultChecking` value of NONE. + +[[mongo-template.writeconcern]] +=== WriteConcern + +You can set the `com.mongodb.WriteConcern` property that the `MongoTemplate` will use for write operations if it has not yet been specified via the driver at a higher level such as `com.mongodb.Mongo`. If MongoTemplate's `WriteConcern` property is not set it will default to the one set in the MongoDB driver's DB or Collection setting. + +[[mongo-template.writeconcernresolver]] +=== WriteConcernResolver + +For more advanced cases where you want to set different `WriteConcern` values on a per-operation basis (for remove, update, insert and save operations), a strategy interface called `WriteConcernResolver` can be configured on `MongoTemplate`. Since `MongoTemplate` is used to persist POJOs, the `WriteConcernResolver` lets you create a policy that can map a specific POJO class to a `WriteConcern` value. The `WriteConcernResolver` interface is shown below. + +[source,java] +---- +public interface WriteConcernResolver { + WriteConcern resolve(MongoAction action); +} +---- + +The passed in argument, MongoAction, is what you use to determine the `WriteConcern` value to be used or to use the value of the Template itself as a default. `MongoAction` contains the collection name being written to, the `java.lang.Class` of the POJO, the converted `DBObject`, as well as the operation as an enumeration (`MongoActionOperation`: REMOVE, UPDATE, INSERT, INSERT_LIST, SAVE) and a few other pieces of contextual information. For example, + +[source] +---- +private class MyAppWriteConcernResolver implements WriteConcernResolver { + + public WriteConcern resolve(MongoAction action) { + if (action.getEntityClass().getSimpleName().contains("Audit")) { + return WriteConcern.NONE; + } else if (action.getEntityClass().getSimpleName().contains("Metadata")) { + return WriteConcern.JOURNAL_SAFE; + } + return action.getDefaultWriteConcern(); + } +} +---- + +[[mongo-template.save-update-remove]] +== Saving, Updating, and Removing Documents + +`MongoTemplate` provides a simple way for you to save, update, and delete your domain objects and map those objects to documents stored in MongoDB. + +Given a simple class such as Person + +[source,java] +---- +public class Person { + + private String id; + private String name; + private int age; + + public Person(String name, int age) { + this.name = name; + this.age = age; + } + + public String getId() { + return id; + } + public String getName() { + return name; + } + public int getAge() { + return age; + } + + @Override + public String toString() { + return "Person [id=" + id + ", name=" + name + ", age=" + age + "]"; + } + +} +---- + +You can save, update and delete the object as shown below. + +NOTE: `MongoOperations` is the interface that `MongoTemplate` implements. + +[source,java] +---- +package org.spring.example; + +import static org.springframework.data.mongodb.core.query.Criteria.where; +import static org.springframework.data.mongodb.core.query.Update.update; +import static org.springframework.data.mongodb.core.query.Query.query; + +import java.util.List; + +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; +import org.springframework.data.mongodb.core.MongoOperations; +import org.springframework.data.mongodb.core.MongoTemplate; +import org.springframework.data.mongodb.core.SimpleMongoDbFactory; + +import com.mongodb.Mongo; + +public class MongoApp { + + private static final Log log = LogFactory.getLog(MongoApp.class); + + public static void main(String[] args) throws Exception { + + MongoOperations mongoOps = new MongoTemplate(new SimpleMongoDbFactory(new Mongo(), "database")); + + Person p = new Person("Joe", 34); + + // Insert is used to initially store the object into the database. + mongoOps.insert(p); + log.info("Insert: " + p); + + // Find + p = mongoOps.findById(p.getId(), Person.class); + log.info("Found: " + p); + + // Update + mongoOps.updateFirst(query(where("name").is("Joe")), update("age", 35), Person.class); + p = mongoOps.findOne(query(where("name").is("Joe")), Person.class); + log.info("Updated: " + p); + + // Delete + mongoOps.remove(p); + + // Check that deletion worked + List people = mongoOps.findAll(Person.class); + log.info("Number of people = : " + people.size()); + + + mongoOps.dropCollection(Person.class); + } +} +---- + +This would produce the following log output (including debug messages from `MongoTemplate` itself) + +[source] +---- +DEBUG apping.MongoPersistentEntityIndexCreator: 80 - Analyzing class class org.spring.example.Person for index information. +DEBUG work.data.mongodb.core.MongoTemplate: 632 - insert DBObject containing fields: [_class, age, name] in collection: person +INFO org.spring.example.MongoApp: 30 - Insert: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=34] +DEBUG work.data.mongodb.core.MongoTemplate:1246 - findOne using query: { "_id" : { "$oid" : "4ddc6e784ce5b1eba3ceaf5c"}} in db.collection: database.person +INFO org.spring.example.MongoApp: 34 - Found: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=34] +DEBUG work.data.mongodb.core.MongoTemplate: 778 - calling update using query: { "name" : "Joe"} and update: { "$set" : { "age" : 35}} in collection: person +DEBUG work.data.mongodb.core.MongoTemplate:1246 - findOne using query: { "name" : "Joe"} in db.collection: database.person +INFO org.spring.example.MongoApp: 39 - Updated: Person [id=4ddc6e784ce5b1eba3ceaf5c, name=Joe, age=35] +DEBUG work.data.mongodb.core.MongoTemplate: 823 - remove using query: { "id" : "4ddc6e784ce5b1eba3ceaf5c"} in collection: person +INFO org.spring.example.MongoApp: 46 - Number of people = : 0 +DEBUG work.data.mongodb.core.MongoTemplate: 376 - Dropped collection [database.person] +---- + +There was implicit conversion using the `MongoConverter` between a `String` and `ObjectId` as stored in the database and recognizing a convention of the property "Id" name. + +NOTE: This example is meant to show the use of save, update and remove operations on MongoTemplate and not to show complex mapping functionality + +The query syntax used in the example is explained in more detail in the section <>. + +[[mongo-template.id-handling]] +=== How the '_id' field is handled in the mapping layer + +MongoDB requires that you have an '_id' field for all documents. If you don't provide one the driver will assign a `ObjectId` with a generated value. When using the `MongoMappingConverter` there are certain rules that govern how properties from the Java class is mapped to this '_id' field. + +The following outlines what property will be mapped to the '_id' document field: + +* A property or field annotated with `@Id` (`org.springframework.data.annotation.Id`) will be mapped to the '_id' field. +* A property or field without an annotation but named `id` will be mapped to the '_id' field. + +The following outlines what type conversion, if any, will be done on the property mapped to the _id document field when using the `MappingMongoConverter`, the default for `MongoTemplate`. + +* An id property or field declared as a String in the Java class will be converted to and stored as an `ObjectId` if possible using a Spring `Converter`. Valid conversion rules are delegated to the MongoDB Java driver. If it cannot be converted to an ObjectId, then the value will be stored as a string in the database. +* An id property or field declared as `BigInteger` in the Java class will be converted to and stored as an `ObjectId` using a Spring `Converter`. + +If no field or property specified above is present in the Java class then an implicit '_id' file will be generated by the driver but not mapped to a property or field of the Java class. + +When querying and updating `MongoTemplate` will use the converter to handle conversions of the `Query` and `Update` objects that correspond to the above rules for saving documents so field names and types used in your queries will be able to match what is in your domain classes. + +[[mongo-template.type-mapping]] +=== Type mapping + +As MongoDB collections can contain documents that represent instances of a variety of types. A great example here is if you store a hierarchy of classes or simply have a class with a property of type `Object`. In the latter case the values held inside that property have to be read in correctly when retrieving the object. Thus we need a mechanism to store type information alongside the actual document. + +To achieve that the `MappingMongoConverter` uses a `MongoTypeMapper` abstraction with `DefaultMongoTypeMapper` as it's main implementation. It's default behaviour is storing the fully qualified classname under `_class` inside the document for the top-level document as well as for every value if it's a complex type and a subtype of the property type declared. + +==== Type mapping + +[source,java] +---- +public class Sample { + Contact value; +} + +public abstract class Contact { … } + +public class Person extends Contact { … } + +Sample sample = new Sample(); +sample.value = new Person(); + +mongoTemplate.save(sample); + +{ "_class" : "com.acme.Sample", + "value" : { "_class" : "com.acme.Person" } +} +---- + +As you can see we store the type information for the actual root class persistent as well as for the nested type as it is complex and a subtype of `Contact`. So if you're now using `mongoTemplate.findAll(Object.class, "sample")` we are able to find out that the document stored shall be a `Sample` instance. We are also able to find out that the value property shall be a `Person` actually. + +==== Customizing type mapping + +In case you want to avoid writing the entire Java class name as type information but rather like to use some key you can use the `@TypeAlias` annotation at the entity class being persisted. If you need to customize the mapping even more have a look at the `TypeInformationMapper` interface. An instance of that interface can be configured at the `DefaultMongoTypeMapper` which can be configured in turn on `MappingMongoConverter`. + +===== Defining a TypeAlias for an Entity + +[source,java] +---- +@TypeAlias("pers") +class Person { + +} +---- + +Note that the resulting document will contain `"pers"` as the value in the `_class` Field. + +==== Configuring custom type mapping + +The following example demonstrates how to configure a custom `MongoTypeMapper` in `MappingMongoConverter`. + +===== Configuring a custom MongoTypeMapper via Spring Java Config + +[source,java] +---- +class CustomMongoTypeMapper extends DefaultMongoTypeMapper { + //implement custom type mapping here +} +---- + +[source,java] +---- +@Configuration +class SampleMongoConfiguration extends AbstractMongoConfiguration { + + @Override + protected String getDatabaseName() { + return "database"; + } + + @Override + public Mongo mongo() throws Exception { + return new Mongo(); + } + + @Bean + @Override + public MappingMongoConverter mappingMongoConverter() throws Exception { + MappingMongoConverter mmc = super.mappingMongoConverter(); + mmc.setTypeMapper(customTypeMapper()); + return mmc; + } + + @Bean + public MongoTypeMapper customTypeMapper() { + return new CustomMongoTypeMapper(); + } +} +---- + +Note that we are extending the `AbstractMongoConfiguration` class and override the bean definition of the `MappingMongoConverter` where we configure our custom `MongoTypeMapper`. + +===== Configuring a custom MongoTypeMapper via XML + +[source,xml] +---- + + + +---- + +[[mongo-template.save-insert]] +=== Methods for saving and inserting documents + +There are several convenient methods on `MongoTemplate` for saving and inserting your objects. To have more fine grained control over the conversion process you can register Spring converters with the `MappingMongoConverter`, for example `Converter` and `Converter`. + +NOTE: The difference between insert and save operations is that a save operation will perform an insert if the object is not already present. + +The simple case of using the save operation is to save a POJO. In this case the collection name will be determined by name (not fully qualfied) of the class. You may also call the save operation with a specific collection name. The collection to store the object can be overriden using mapping metadata. + +When inserting or saving, if the Id property is not set, the assumption is that its value will be auto-generated by the database. As such, for auto-generation of an ObjectId to succeed the type of the Id property/field in your class must be either a `String`, `ObjectId`, or `BigInteger`. + +Here is a basic example of using the save operation and retrieving its contents. + +==== Inserting and retrieving documents using the MongoTemplate + +[source,java] +---- +import static org.springframework.data.mongodb.core.query.Criteria.where; +import static org.springframework.data.mongodb.core.query.Criteria.query; +… + +Person p = new Person("Bob", 33); +mongoTemplate.insert(p); + +Person qp = mongoTemplate.findOne(query(where("age").is(33)), Person.class); +---- + +The insert/save operations available to you are listed below. + +* `void` *save* `(Object objectToSave)` Save the object to the default collection. +* `void` *save* `(Object objectToSave, String collectionName)` Save the object to the specified collection. + +A similar set of insert operations is listed below + +* `void` *insert* `(Object objectToSave)` Insert the object to the default collection. +* `void` *insert* `(Object objectToSave, String collectionName)` Insert the object to the specified collection. + +[[mongo-template.save-insert.collection]] +==== Which collection will my documents be saved into? + +There are two ways to manage the collection name that is used for operating on the documents. The default collection name that is used is the class name changed to start with a lower-case letter. So a `com.test.Person` class would be stored in the "person" collection. You can customize this by providing a different collection name using the @Document annotation. You can also override the collection name by providing your own collection name as the last parameter for the selected MongoTemplate method calls. + +[[mongo-template.save-insert.individual]] +==== Inserting or saving individual objects + +The MongoDB driver supports inserting a collection of documents in one operation. The methods in the MongoOperations interface that support this functionality are listed below + +* *insert* inserts an object. If there is an existing document with the same id then an error is generated. +* *insertAll* takes a `Collection `of objects as the first parameter. This method inspects each object and inserts it to the appropriate collection based on the rules specified above. +* *save* saves the object overwriting any object that might exist with the same id. + +[[mongo-template.save-insert.batch]] +==== Inserting several objects in a batch + +The MongoDB driver supports inserting a collection of documents in one operation. The methods in the MongoOperations interface that support this functionality are listed below + +* *insert*` methods that take a `Collection` as the first argument. This inserts a list of objects in a single batch write to the database. + +[[mongodb-template-update]] +=== Updating documents in a collection + +For updates we can elect to update the first document found using `MongoOperation`'s method `updateFirst` or we can update all documents that were found to match the query using the method `updateMulti`. Here is an example of an update of all SAVINGS accounts where we are adding a one time $50.00 bonus to the balance using the `$inc` operator. + +==== Updating documents using the MongoTemplate + +[source,java] +---- +import static org.springframework.data.mongodb.core.query.Criteria.where; +import static org.springframework.data.mongodb.core.query.Query; +import static org.springframework.data.mongodb.core.query.Update; + +... + +WriteResult wr = mongoTemplate.updateMulti(new Query(where("accounts.accountType").is(Account.Type.SAVINGS)), + new Update().inc("accounts.$.balance", 50.00), Account.class); +---- + +In addition to the `Query` discussed above we provide the update definition using an `Update` object. The `Update` class has methods that match the update modifiers available for MongoDB. + +As you can see most methods return the `Update` object to provide a fluent style for the API. + +[[mongodb-template-update.methods]] +==== Methods for executing updates for documents + +* *updateFirst* Updates the first document that matches the query document criteria with the provided updated document. +* *updateMulti* Updates all objects that match the query document criteria with the provided updated document. + +[[mongodb-template-update.update]] +==== Methods for the Update class + +The Update class can be used with a little 'syntax sugar' as its methods are meant to be chained together and you can kick-start the creation of a new Update instance via the static method `public static Update update(String key, Object value)` and using static imports. + +Here is a listing of methods on the Update class + +* `Update` *addToSet* `(String key, Object value) ` Update using the `$addToSet` update modifier +* `Update` *inc* `(String key, Number inc)` Update using the `$inc` update modifier +* `Update` *pop* `(String key, Update.Position pos)` Update using the `$pop` update modifier +* `Update` *pull* `(String key, Object value)` Update using the `$pull` update modifier +* `Update` *pullAll* `(String key, Object[] values)` Update using the `$pullAll` update modifier +* `Update` *push* `(String key, Object value) ` Update using the `$push` update modifier +* `Update` *pushAll* `(String key, Object[] values)` Update using the `$pushAll` update modifier +* `Update` *rename* `(String oldName, String newName)` Update using the `$rename` update modifier +* `Update` *set* `(String key, Object value)` Update using the `$set` update modifier +* `Update` *unset* `(String key)` Update using the `$unset` update modifier + +[[mongo-template.upserts]] +=== Upserting documents in a collection + +Related to performing an `updateFirst` operations, you can also perform an upsert operation which will perform an insert if no document is found that matches the query. The document that is inserted is a combination of the query document and the update document. Here is an example + +[source] +---- +template.upsert(query(where("ssn").is(1111).and("firstName").is("Joe").and("Fraizer").is("Update")), update("address", addr), Person.class); +---- + +[[mongo-template.find-and-upsert]] +=== Finding and Upserting documents in a collection + +The `findAndModify(…)` method on DBCollection can update a document and return either the old or newly updated document in a single operation. `MongoTemplate` provides a findAndModify method that takes `Query` and `Update` classes and converts from `DBObject` to your POJOs. Here are the methods + +[source,java] +---- + T findAndModify(Query query, Update update, Class entityClass); + + T findAndModify(Query query, Update update, Class entityClass, String collectionName); + + T findAndModify(Query query, Update update, FindAndModifyOptions options, Class entityClass); + + T findAndModify(Query query, Update update, FindAndModifyOptions options, Class entityClass, String collectionName); +---- + +As an example usage, we will insert of few `Person` objects into the container and perform a simple findAndUpdate operation + +[source,java] +---- +mongoTemplate.insert(new Person("Tom", 21)); +mongoTemplate.insert(new Person("Dick", 22)); +mongoTemplate.insert(new Person("Harry", 23)); + +Query query = new Query(Criteria.where("firstName").is("Harry")); +Update update = new Update().inc("age", 1); +Person p = mongoTemplate.findAndModify(query, update, Person.class); // return's old person object + +assertThat(p.getFirstName(), is("Harry")); +assertThat(p.getAge(), is(23)); +p = mongoTemplate.findOne(query, Person.class); +assertThat(p.getAge(), is(24)); + +// Now return the newly updated document when updating +p = template.findAndModify(query, update, new FindAndModifyOptions().returnNew(true), Person.class); +assertThat(p.getAge(), is(25)); +---- + +The `FindAndModifyOptions` lets you set the options of returnNew, upsert, and remove. An example extending off the previous code snippit is shown below + +[source,java] +---- +Query query2 = new Query(Criteria.where("firstName").is("Mary")); +p = mongoTemplate.findAndModify(query2, update, new FindAndModifyOptions().returnNew(true).upsert(true), Person.class); +assertThat(p.getFirstName(), is("Mary")); +assertThat(p.getAge(), is(1)); +---- + +[[mongo-template.delete]] +=== Methods for removing documents + +You can use several overloaded methods to remove an object from the database. + +* *remove* Remove the given document based on one of the following: a specific object instance, a query document criteria combined with a class or a query document criteria combined with a specific collection name. + +[[mongo.query]] +== Querying Documents + +You can express your queries using the `Query` and `Criteria` classes which have method names that mirror the native MongoDB operator names such as `lt`, `lte`, `is`, and others. The `Query` and `Criteria` classes follow a fluent API style so that you can easily chain together multiple method criteria and queries while having easy to understand code. Static imports in Java are used to help remove the need to see the 'new' keyword for creating `Query` and `Criteria` instances so as to improve readability. If you like to create `Query` instances from a plain JSON String use `BasicQuery`. + +=== Creating a Query instance from a plain JSON String + +[source,java] +---- +BasicQuery query = new BasicQuery("{ age : { $lt : 50 }, accounts.balance : { $gt : 1000.00 }}"); +List result = mongoTemplate.find(query, Person.class); +---- + +GeoSpatial queries are also supported and are described more in the section <>. + +Map-Reduce operations are also supported and are described more in the section <>. + +[[mongodb-template-query]] +=== Querying documents in a collection + +We saw how to retrieve a single document using the findOne and findById methods on MongoTemplate in previous sections which return a single domain object. We can also query for a collection of documents to be returned as a list of domain objects. Assuming that we have a number of Person objects with name and age stored as documents in a collection and that each person has an embedded account document with a balance. We can now run a query using the following code. + +==== Querying for documents using the MongoTemplate + +[source,java] +---- +import static org.springframework.data.mongodb.core.query.Criteria.where; +import static org.springframework.data.mongodb.core.query.Query.query; + +… + +List result = mongoTemplate.find(query(where("age").lt(50) + .and("accounts.balance").gt(1000.00d)), Person.class); +---- + +All find methods take a `Query` object as a parameter. This object defines the criteria and options used to perform the query. The criteria is specified using a `Criteria` object that has a static factory method named `where` used to instantiate a new `Criteria` object. We recommend using a static import for `org.springframework.data.mongodb.core.query.Criteria.where` and `Query.query` to make the query more readable. + +This query should return a list of `Person` objects that meet the specified criteria. The `Criteria` class has the following methods that correspond to the operators provided in MongoDB. + +As you can see most methods return the `Criteria` object to provide a fluent style for the API. + +[[mongodb-template-query.criteria]] +==== Methods for the Criteria class + +* `Criteria` *all* `(Object o)` Creates a criterion using the `$all` operator +* `Criteria` *and* `(String key)` Adds a chained `Criteria` with the specified `key` to the current `Criteria` and returns the newly created one +* `Criteria` *andOperator* `(Criteria... criteria)` Creates an and query using the `$and` operator for all of the provided criteria (requires MongoDB 2.0 or later) +* `Criteria` *elemMatch* `(Criteria c)` Creates a criterion using the `$elemMatch` operator +* `Criteria` *exists* `(boolean b)` Creates a criterion using the `$exists` operator +* `Criteria` *gt* `(Object o)` Creates a criterion using the `$gt` operator +* `Criteria` *gte* `(Object o)` Creates a criterion using the `$gte` operator +* `Criteria` *in* `(Object... o)` Creates a criterion using the `$in` operator for a varargs argument. +* `Criteria` *in* `(Collection collection)` Creates a criterion using the `$in` operator using a collection +* `Criteria` *is* `(Object o)` Creates a criterion using the `$is` operator +* `Criteria` *lt* `(Object o)` Creates a criterion using the `$lt` operator +* `Criteria` *lte* `(Object o)` Creates a criterion using the `$lte` operator +* `Criteria` *mod* `(Number value, Number remainder)` Creates a criterion using the `$mod` operator +* `Criteria` *ne* `(Object o)` Creates a criterion using the `$ne` operator +* `Criteria` *nin* `(Object... o)` Creates a criterion using the `$nin` operator +* `Criteria` *norOperator* `(Criteria... criteria)` Creates an nor query using the `$nor` operator for all of the provided criteria +* `Criteria` *not* `()` Creates a criterion using the `$not` meta operator which affects the clause directly following +* `Criteria` *orOperator* `(Criteria... criteria)` Creates an or query using the `$or` operator for all of the provided criteria +* `Criteria` *regex* `(String re)` Creates a criterion using a `$regex` +* `Criteria` *size* `(int s)` Creates a criterion using the `$size` operator +* `Criteria` *type* `(int t)` Creates a criterion using the `$type` operator + +There are also methods on the Criteria class for geospatial queries. Here is a listing but look at the section on <> to see them in action. + +* `Criteria` *withinCenter* `(Circle circle)` Creates a geospatial criterion using `$within $center` operators +* `Criteria` *withinCenterSphere* `(Circle circle)` Creates a geospatial criterion using `$within $center` operators. This is only available for MongoDB 1.7 and higher. +* `Criteria` *withinBox* `(Box box)` Creates a geospatial criterion using a `$within $box` operation `` +* `Criteria` *near* `(Point point)` Creates a geospatial criterion using a `$near `operation +* `Criteria` *nearSphere* `(Point point)` Creates a geospatial criterion using `$nearSphere$center` operations. This is only available for MongoDB 1.7 and higher. +* `Criteria` *maxDistance* `(double maxDistance)` Creates a geospatial criterion using the `$maxDistance` operation, for use with $near. + +The `Query` class has some additional methods used to provide options for the query. + +[[mongodb-template-query.query]] +==== Methods for the Query class + +* `Query` *addCriteria* `(Criteria criteria)` used to add additional criteria to the query +* `Field` *fields* `()` used to define fields to be included in the query results +* `Query` *limit* `(int limit)` used to limit the size of the returned results to the provided limit (used for paging) +* `Query` *skip* `(int skip)` used to skip the provided number of documents in the results (used for paging) +* `Sort` *sort* `()` used to provide sort definition for the results + +[[mongo-template.querying]] +=== Methods for querying for documents + +The query methods need to specify the target type T that will be returned and they are also overloaded with an explicit collection name for queries that should operate on a collection other than the one indicated by the return type. + +* *findAll* Query for a list of objects of type T from the collection. +* *findOne* Map the results of an ad-hoc query on the collection to a single instance of an object of the specified type. +* *findById* Return an object of the given id and target class. +* *find* Map the results of an ad-hoc query on the collection to a List of the specified type. +* *findAndRemove* Map the results of an ad-hoc query on the collection to a single instance of an object of the specified type. The first document that matches the query is returned and also removed from the collection in the database. + +[[mongo.geospatial]] +=== GeoSpatial Queries + +MongoDB supports GeoSpatial queries through the use of operators such as `$near`, `$within`, and `$nearSphere`. Methods specific to geospatial queries are available on the `Criteria` class. There are also a few shape classes, `Box`, `Circle`, and `Point` that are used in conjunction with geospatial related `Criteria` methods. + +To understand how to perform GeoSpatial queries we will use the following Venue class taken from the integration tests.which relies on using the rich `MappingMongoConverter`. + +[source,java] +---- +@Document(collection="newyork") +public class Venue { + + @Id + private String id; + private String name; + private double[] location; + + @PersistenceConstructor + Venue(String name, double[] location) { + super(); + this.name = name; + this.location = location; + } + + public Venue(String name, double x, double y) { + super(); + this.name = name; + this.location = new double[] { x, y }; + } + + public String getName() { + return name; + } + + public double[] getLocation() { + return location; + } + + @Override + public String toString() { + return "Venue [id=" + id + ", name=" + name + ", location=" + + Arrays.toString(location) + "]"; + } +} +---- + +To find locations within a `Circle`, the following query can be used. + +[source,java] +---- +Circle circle = new Circle(-73.99171, 40.738868, 0.01); +List venues = + template.find(new Query(Criteria.where("location").withinCenter(circle)), Venue.class); +---- + +To find venues within a `Circle` using spherical coordinates the following query can be used + +[source,java] +---- +Circle circle = new Circle(-73.99171, 40.738868, 0.003712240453784); +List venues = + template.find(new Query(Criteria.where("location").withinCenterSphere(circle)), Venue.class); +---- + +To find venues within a `Box` the following query can be used + +[source,java] +---- +//lower-left then upper-right +Box box = new Box(new Point(-73.99756, 40.73083), new Point(-73.988135, 40.741404)); +List venues = + template.find(new Query(Criteria.where("location").withinBox(box)), Venue.class); +---- + +To find venues near a `Point`, the following query can be used + +[source,java] +---- +Point point = new Point(-73.99171, 40.738868); +List venues = + template.find(new Query(Criteria.where("location").near(point).maxDistance(0.01)), Venue.class); +---- + +To find venues near a `Point` using spherical coordines the following query can be used + +[source,java] +---- +Point point = new Point(-73.99171, 40.738868); +List venues = + template.find(new Query( + Criteria.where("location").nearSphere(point).maxDistance(0.003712240453784)), + Venue.class); +---- + +[[mongo.geo-near]] +==== Geo near queries + +MongoDB supports querying the database for geo locations and calculation the distance from a given origin at the very same time. With geo-near queries it's possible to express queries like: "find all restaurants in the surrounding 10 miles". To do so `MongoOperations` provides `geoNear(…)` methods taking a `NearQuery` as argument as well as the already familiar entity type and collection + +[source,java] +---- +Point location = new Point(-73.99171, 40.738868); +NearQuery query = NearQuery.near(location).maxDistance(new Distance(10, Metrics.MILES)); + +GeoResults = operations.geoNear(query, Restaurant.class); +---- + +As you can see we use the `NearQuery` builder API to set up a query to return all `Restaurant` instances surrounding the given `Point` by 10 miles maximum. The `Metrics` enum used here actually implements an interface so that other metrics could be plugged into a distance as well. A `Metric` is backed by a multiplier to transform the distance value of the given metric into native distances. The sample shown here would consider the 10 to be miles. Using one of the pre-built in metrics (miles and kilometers) will automatically trigger the spherical flag to be set on the query. If you want to avoid that, simply hand in plain `double` values into `maxDistance(…)`. For more information see the JavaDoc of `NearQuery` and `Distance`. + +The geo near operations return a `GeoResults` wrapper object that encapsulates `GeoResult` instances. The wrapping `GeoResults` allows to access the average distance of all results. A single `GeoResult` object simply carries the entity found plus its distance from the origin. + +[[mongo.textsearch]] +=== Full Text Queries + +Since MongoDB 2.6 full text queries can be executed using the `$text` operator. Methods and operations specific for full text queries are available in `TextQuery` and `TextCriteria`. When doing full text search please refer to the http://docs.mongodb.org/manual/reference/operator/query/text/#behavior[MongoDB reference] for its behavior and limitations. + +==== Full Text Search + +Before we are actually able to use full text search we have to ensure to set up the search index correctly. Please refer to section <> for creating index structures. + +[source,javascript] +---- +db.foo.ensureIndex( +{ + title : "text", + content : "text" +}, +{ + weights : { + title : 3 + } +} +) +---- + +A query searching for `coffee cake`, sorted by relevance according to the `weights` can be defined and executed as: + +[source,java] +---- +Query query = TextQuery.searching(new TextCriteria().matchingAny("coffee", "cake")).sortByScore(); +List page = template.find(query, Document.class); +---- + +Exclusion of search terms can directly be done by prefixing the term with `-` or using `notMatching` + +[source,java] +---- +// search for 'coffee' and not 'cake' +TextQuery.searching(new TextCriteria().matching("coffee").matching("-cake")); +TextQuery.searching(new TextCriteria().matching("coffee").notMatching("cake")); +---- + +As `TextCriteria.matching` takes the provided term as is. Therefore phrases can be defined by putting them between double quotes (eg. `\"coffee cake\")` or using `TextCriteria.phrase.` + +[source,java] +---- +// search for phrase 'coffee cake' +TextQuery.searching(new TextCriteria().matching("\"coffee cake\"")); +TextQuery.searching(new TextCriteria().phrase("coffee cake")); +---- + +[[mongo.mapreduce]] +== Map-Reduce Operations + +You can query MongoDB using Map-Reduce which is useful for batch processing, data aggregation, and for when the query language doesn't fulfill your needs. + +Spring provides integration with MongoDB's map reduce by providing methods on MongoOperations to simplify the creation and execution of Map-Reduce operations. It can convert the results of a Map-Reduce operation to a POJO also integrates with Spring's http://docs.spring.io/spring/docs/current/spring-framework-reference/html/resources.html[Resource abstraction] abstraction. This will let you place your JavaScript files on the file system, classpath, http server or any other Spring Resource implementation and then reference the JavaScript resources via an easy URI style syntax, e.g. 'classpath:reduce.js;. Externalizing JavaScript code in files is often preferable to embedding them as Java strings in your code. Note that you can still pass JavaScript code as Java strings if you prefer. + +[[mongo.mapreduce.example]] +=== Example Usage + +To understand how to perform Map-Reduce operations an example from the book 'MongoDB - The definitive guide' is used. In this example we will create three documents that have the values [a,b], [b,c], and [c,d] respectfully. The values in each document are associated with the key 'x' as shown below. For this example assume these documents are in the collection named "jmr1". + +[source] +---- +{ "_id" : ObjectId("4e5ff893c0277826074ec533"), "x" : [ "a", "b" ] } +{ "_id" : ObjectId("4e5ff893c0277826074ec534"), "x" : [ "b", "c" ] } +{ "_id" : ObjectId("4e5ff893c0277826074ec535"), "x" : [ "c", "d" ] } +---- + +A map function that will count the occurrence of each letter in the array for each document is shown below + +[source,java] +---- +function () { + for (var i = 0; i < this.x.length; i++) { + emit(this.x[i], 1); + } +} +---- + +The reduce function that will sum up the occurrence of each letter across all the documents is shown below + +[source,java] +---- +function (key, values) { + var sum = 0; + for (var i = 0; i < values.length; i++) + sum += values[i]; + return sum; +} +---- + +Executing this will result in a collection as shown below. + +[source] +---- +{ "_id" : "a", "value" : 1 } +{ "_id" : "b", "value" : 2 } +{ "_id" : "c", "value" : 2 } +{ "_id" : "d", "value" : 1 } +---- + +Assuming that the map and reduce functions are located in map.js and reduce.js and bundled in your jar so they are available on the classpath, you can execute a map-reduce operation and obtain the results as shown below + +[source,java] +---- +MapReduceResults results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", ValueObject.class); +for (ValueObject valueObject : results) { + System.out.println(valueObject); +} +---- + +The output of the above code is + +[source] +---- +ValueObject [id=a, value=1.0] +ValueObject [id=b, value=2.0] +ValueObject [id=c, value=2.0] +ValueObject [id=d, value=1.0] +---- + +The MapReduceResults class implements `Iterable` and provides access to the raw output, as well as timing and count statistics. The `ValueObject` class is simply + +[source,java] +---- +public class ValueObject { + + private String id; + private float value; + + public String getId() { + return id; + } + + public float getValue() { + return value; + } + + public void setValue(float value) { + this.value = value; + } + + @Override + public String toString() { + return "ValueObject [id=" + id + ", value=" + value + "]"; + } +} +---- + +By default the output type of INLINE is used so you don't have to specify an output collection. To specify additional map-reduce options use an overloaded method that takes an additional `MapReduceOptions` argument. The class `MapReduceOptions` has a fluent API so adding additional options can be done in a very compact syntax. Here an example that sets the output collection to "jmr1_out". Note that setting only the output collection assumes a default output type of REPLACE. + +[source,java] +---- +MapReduceResults results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", + new MapReduceOptions().outputCollection("jmr1_out"), ValueObject.class); +---- + +There is also a static import `import static org.springframework.data.mongodb.core.mapreduce.MapReduceOptions.options;` that can be used to make the syntax slightly more compact + +[source,java] +---- +MapReduceResults results = mongoOperations.mapReduce("jmr1", "classpath:map.js", "classpath:reduce.js", + options().outputCollection("jmr1_out"), ValueObject.class); +---- + +You can also specify a query to reduce the set of data that will be used to feed into the map-reduce operation. This will remove the document that contains [a,b] from consideration for map-reduce operations. + +[source,java] +---- +Query query = new Query(where("x").ne(new String[] { "a", "b" })); +MapReduceResults results = mongoOperations.mapReduce(query, "jmr1", "classpath:map.js", "classpath:reduce.js", + options().outputCollection("jmr1_out"), ValueObject.class); +---- + +Note that you can specify additional limit and sort values as well on the query but not skip values. + +[[mongo.group]] +== Group Operations + +As an alternative to using Map-Reduce to perform data aggregation, you can use the http://www.mongodb.org/display/DOCS/Aggregation#Aggregation-Group[`group` operation] which feels similar to using SQL's group by query style, so it may feel more approachable vs. using Map-Reduce. Using the group operations does have some limitations, for example it is not supported in a shareded environment and it returns the full result set in a single BSON object, so the result should be small, less than 10,000 keys. + +Spring provides integration with MongoDB's group operation by providing methods on MongoOperations to simplify the creation and execution of group operations. It can convert the results of the group operation to a POJO and also integrates with Spring's http://docs.spring.io/spring/docs/current/spring-framework-reference/html/resources.html[Resource abstraction] abstraction. This will let you place your JavaScript files on the file system, classpath, http server or any other Spring Resource implementation and then reference the JavaScript resources via an easy URI style syntax, e.g. 'classpath:reduce.js;. Externalizing JavaScript code in files if often preferable to embedding them as Java strings in your code. Note that you can still pass JavaScript code as Java strings if you prefer. + +[[mongo.group.example]] +=== Example Usage + +In order to understand how group operations work the following example is used, which is somewhat artificial. For a more realistic example consult the book 'MongoDB - The definitive guide'. A collection named "group_test_collection" created with the following rows. + +[source] +---- +{ "_id" : ObjectId("4ec1d25d41421e2015da64f1"), "x" : 1 } +{ "_id" : ObjectId("4ec1d25d41421e2015da64f2"), "x" : 1 } +{ "_id" : ObjectId("4ec1d25d41421e2015da64f3"), "x" : 2 } +{ "_id" : ObjectId("4ec1d25d41421e2015da64f4"), "x" : 3 } +{ "_id" : ObjectId("4ec1d25d41421e2015da64f5"), "x" : 3 } +{ "_id" : ObjectId("4ec1d25d41421e2015da64f6"), "x" : 3 } +---- + +We would like to group by the only field in each row, the 'x' field and aggregate the number of times each specific value of 'x' occurs. To do this we need to create an initial document that contains our count variable and also a reduce function which will increment it each time it is encountered. The Java code to execute the group operation is shown below + +[source,java] +---- +GroupByResults results = mongoTemplate.group("group_test_collection", + GroupBy.key("x").initialDocument("{ count: 0 }").reduceFunction("function(doc, prev) { prev.count += 1 }"), + XObject.class); +---- + +The first argument is the name of the collection to run the group operation over, the second is a fluent API that specifies properties of the group operation via a `GroupBy` class. In this example we are using just the `intialDocument` and `reduceFunction` methods. You can also specify a key-function, as well as a finalizer as part of the fluent API. If you have multiple keys to group by, you can pass in a comma separated list of keys. + +The raw results of the group operation is a JSON document that looks like this + +[source] +---- +{ + "retval" : [ { "x" : 1.0 , "count" : 2.0} , + { "x" : 2.0 , "count" : 1.0} , + { "x" : 3.0 , "count" : 3.0} ] , + "count" : 6.0 , + "keys" : 3 , + "ok" : 1.0 +} +---- + +The document under the "retval" field is mapped onto the third argument in the group method, in this case XObject which is shown below. + +[source,java] +---- +public class XObject { + + private float x; + + private float count; + + + public float getX() { + return x; + } + + public void setX(float x) { + this.x = x; + } + + public float getCount() { + return count; + } + + public void setCount(float count) { + this.count = count; + } + + @Override + public String toString() { + return "XObject [x=" + x + " count = " + count + "]"; + } +} +---- + +You can also obtain the raw result as a `DbObject` by calling the method `getRawResults` on the `GroupByResults` class. + +There is an additional method overload of the group method on `MongoOperations` which lets you specify a `Criteria` object for selecting a subset of the rows. An example which uses a `Criteria` object, with some syntax sugar using static imports, as well as referencing a key-function and reduce function javascript files via a Spring Resource string is shown below. + +[source] +---- +import static org.springframework.data.mongodb.core.mapreduce.GroupBy.keyFunction; +import static org.springframework.data.mongodb.core.query.Criteria.where; + +GroupByResults results = mongoTemplate.group(where("x").gt(0), + "group_test_collection", + keyFunction("classpath:keyFunction.js").initialDocument("{ count: 0 }").reduceFunction("classpath:groupReduce.js"), XObject.class); +---- + +[[mongo.aggregation]] +== Aggregation Framework Support + +Spring Data MongoDB provides support for the Aggregation Framework introduced to MongoDB in version 2.2. + +The MongoDB Documentation describes the http://docs.mongodb.org/manual/core/aggregation/[Aggregation Framework] as follows: + +For further information see the full http://docs.mongodb.org/manual/aggregation/[reference documentation] of the aggregation framework and other data aggregation tools for MongoDB. + +[[mongo.aggregation.basic-concepts]] +=== Basic Concepts + +The Aggregation Framework support in Spring Data MongoDB is based on the following key abstractions `Aggregation`, `AggregationOperation` and `AggregationResults`. + +* `Aggregation` ++ +An Aggregation represents a MongoDB `aggregate` operation and holds the description of the aggregation pipline instructions. Aggregations are created by inoking the appropriate `newAggregation(…)` static factory Method of the `Aggregation` class which takes the list of `AggregateOperation` as a parameter next to the optional input class. ++ +The actual aggregate operation is executed by the `aggregate` method of the `MongoTemplate` which also takes the desired output class as parameter. ++ +* `AggregationOperation` ++ +An `AggregationOperation` represents a MongoDB aggregation pipeline operation and describes the processing that should be performed in this aggregation step. Although one could manually create an `AggregationOperation` the recommended way to construct an `AggregateOperation` is to use the static factory methods provided by the `Aggregate` class. ++ +* `AggregationResults` ++ +`AggregationResults` is the container for the result of an aggregate operation. It provides access to the raw aggregation result in the form of an `DBObject`, to the mapped objects and information which performed the aggregation. ++ +The canonical example for using the Spring Data MongoDB support for the MongoDB Aggregation Framework looks as follows: + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +Aggregation agg = newAggregation( + pipelineOP1(), + pipelineOP2(), + pipelineOPn() +); + +AggregationResults results = mongoTemplate.aggregate(agg, "INPUT_COLLECTION_NAME", OutputType.class); +List mappedResult = results.getMappedResults(); +---- + +Note that if you provide an input class as the first parameter to the `newAggregation` method the `MongoTemplate` will derive the name of the input collection from this class. Otherwise if you don't not specify an input class you must provide the name of the input collection explicitly. If an input-class and an input-collection is provided the latter takes precedence. + +[[mongo.aggregation.supported-aggregation-operations]] +=== Supported Aggregation Operations + +The MongoDB Aggregation Framework provides the following types of Aggregation Operations: + +* Pipeline Aggregation Operators +* Group Aggregation Operators +* Boolean Aggregation Operators +* Comparison Aggregation Operators +* Arithmetic Aggregation Operators +* String Aggregation Operators +* Date Aggregation Operators +* Conditional Aggregation Operators + +At the time of this writing we provide support for the following Aggregation Operations in Spring Data MongoDB. + +.Aggregation Operations currently supported by Spring Data MongoDB +[cols="2*"] +|=== +| Pipeline Aggregation Operators +| project, skip, limit, unwind, group, sort, geoNear + +| Group Aggregation Operators +| addToSet, first, last, max, min, avg, push, sum, (*count) + +| Arithmetic Aggregation Operators +| add (*via plus), subtract (*via minus), multiply, divide, mod + +| Comparison Aggregation Operators +| eq (*via: is), gt, gte, lt, lte, ne +|=== + +Note that the aggregation operations not listed here are currently not supported by Spring Data MongoDB. Comparison aggregation operators are expressed as `Criteria` expressions. + +*) The operation is mapped or added by Spring Data MongoDB. + +[[mongo.aggregation.projection]] +=== Projection Expressions + +Projection expressions are used to define the fields that are the outcome of a particular aggregation step. Projection expressions can be defined via the `project` method of the `Aggregate` class. + +==== Projection expression examples + +[source,java] +---- +project("name", "netPrice") // will generate {$project: {name: 1, netPrice: 1}} +project().and("foo").as("bar") // will generate {$project: {bar: $foo}} +project("a","b").and("foo").as("bar") // will generate {$project: {a: 1, b: 1, bar: $foo}} +---- + +Note that more examples for project operations can be found in the `AggregationTests` class. + +Note that further details regarding the projection expressions can be found in the http://docs.mongodb.org/manual/reference/operator/aggregation/project/#pipe._S_project[corresponding section] of the MongoDB Aggregation Framework reference documentation. + +[[mongo.aggregation.projection.expressions]] +==== Spring Expression Support in Projection Expressions + +As of Version 1.4.0 we support the use of SpEL expression in projection expressions via the `andExpression` method of the `ProjectionOperation` class. This allows you to define the desired expression as a SpEL expression which is translated into a corresponding MongoDB projection expression part on query execution. This makes it much easier to express complex calculations. + +===== Complex calculations with SpEL expressions + +The following SpEL expression: + +[source,java] +---- +1 + (q + 1) / (q - 1) +---- + +will be translated into the following projection expression part: + +[source,javascript] +---- +{ "$add" : [ 1, { + "$divide" : [ { + "$add":["$q", 1]}, { + "$subtract":[ "$q", 1]} + ] +}]} +---- + +Have a look at an example in more context in <> and <>. You can find more usage examples for supported SpEL expression constructs in `SpelExpressionTransformerUnitTests`. + +[[mongo.aggregation.examples]] +==== Aggregation Framework Examples + +The following examples demonstrate the usage patterns for the MongoDB Aggregation Framework with Spring Data MongoDB. + +[[mongo.aggregation.examples.example1]] +==== Aggregation Framework Example 1 + +In this introductory example we want to aggregate a list of tags to get the occurrence count of a particular tag from a MongoDB collection called `"tags"` sorted by the occurrence count in descending order. This example demonstrates the usage of grouping, sorting, projections (selection) and unwinding (result splitting). + +[source,java] +---- +class TagCount { + String tag; + int n; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +Aggregation agg = newAggregation( + project("tags"), + unwind("tags"), + group("tags").count().as("n"), + project("n").and("tag").previousOperation(), + sort(DESC, "n") +); + +AggregationResults results = mongoTemplate.aggregate(agg, "tags", TagCount.class); +List tagCount = results.getMappedResults(); +---- + +* In order to do this we first create a new aggregation via the `newAggregation` static factory method to which we pass a list of aggregation operations. These aggregate operations define the aggregation pipeline of our `Aggregation`. +* As a second step we select the `"tags"` field (which is an array of strings) from the input collection with the `project` operation. +* In a third step we use the `unwind` operation to generate a new document for each tag within the `"tags"` array. +* In the forth step we use the `group` operation to define a group for each `"tags"`-value for which we aggregate the occurrence count via the `count` aggregation operator and collect the result in a new field called `"n"`. +* As a fifth step we select the field `"n"` and create an alias for the id-field generated from the previous group operation (hence the call to `previousOperation()`) with the name `"tag"`. +* As the sixth step we sort the resulting list of tags by their occurrence count in descending order via the `sort` operation. +* Finally we call the `aggregate` Method on the MongoTemplate in order to let MongoDB perform the acutal aggregation operation with the created `Aggregation` as an argument. + +Note that the input collection is explicitly specified as the `"tags"` parameter to the `aggregate` Method. If the name of the input collection is not specified explicitly, it is derived from the input-class passed as first parameter to the `newAggreation` Method. + +[[mongo.aggregation.examples.example2]] +==== Aggregation Framework Example 2 + +This example is based on the http://docs.mongodb.org/manual/tutorial/aggregation-examples/#largest-and-smallest-cities-by-state[Largest and Smallest Cities by State] example from the MongoDB Aggregation Framework documentation. We added additional sorting to produce stable results with different MongoDB versions. Here we want to return the smallest and largest cities by population for each state, using the aggregation framework. This example demonstrates the usage of grouping, sorting and projections (selection). + +[source,java] +---- +class ZipInfo { + String id; + String city; + String state; + @Field("pop") int population; + @Field("loc") double[] location; +} + +class City { + String name; + int population; +} + +class ZipInfoStats { + String id; + String state; + City biggestCity; + City smallestCity; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +TypedAggregation aggregation = newAggregation(ZipInfo.class, + group("state", "city") + .sum("population").as("pop"), + sort(ASC, "pop", "state", "city"), + group("state") + .last("city").as("biggestCity") + .last("pop").as("biggestPop") + .first("city").as("smallestCity") + .first("pop").as("smallestPop"), + project() + .and("state").previousOperation() + .and("biggestCity") + .nested(bind("name", "biggestCity").and("population", "biggestPop")) + .and("smallestCity") + .nested(bind("name", "smallestCity").and("population", "smallestPop")), + sort(ASC, "state") +); + +AggregationResults result = mongoTemplate.aggregate(aggregation, ZipInfoStats.class); +ZipInfoStats firstZipInfoStats = result.getMappedResults().get(0); +---- + +* The class `ZipInfo` maps the structure of the given input-collection. The class `ZipInfoStats` defines the structure in the desired output format. +* As a first step we use the `group` operation to define a group from the input-collection. The grouping criteria is the combination of the fields `"state"` and `"city" `which forms the id structure of the group. We aggregate the value of the `"population"` property from the grouped elements with by using the `sum` operator saving the result in the field `"pop"`. +* In a second step we use the `sort` operation to sort the intermediate-result by the fields `"pop"`, `"state"` and `"city"` in ascending order, such that the smallest city is at the top and the biggest city is at the bottom of the result. Note that the sorting on "state" and `"city"` is implicitly performed against the group id fields which Spring Data MongoDB took care of. +* In the third step we use a `group` operation again to group the intermediate result by `"state"`. Note that `"state"` again implicitly references an group-id field. We select the name and the population count of the biggest and smallest city with calls to the `last(…)` and `first(...)` operator respectively via the `project` operation. +* As the forth step we select the `"state"` field from the previous `group` operation. Note that `"state"` again implicitly references an group-id field. As we do not want an implicit generated id to appear, we exclude the id from the previous operation via `and(previousOperation()).exclude()`. As we want to populate the nested `City` structures in our output-class accordingly we have to emit appropriate sub-documents with the nested method. +* Finally as the fifth step we sort the resulting list of `StateStats` by their state name in ascending order via the `sort` operation. + +Note that we derive the name of the input-collection from the `ZipInfo`-class passed as first parameter to the `newAggregation`-Method. + +[[mongo.aggregation.examples.example3]] +==== Aggregation Framework Example 3 + +This example is based on the http://docs.mongodb.org/manual/tutorial/aggregation-examples/#states-with-populations-over-10-million[States with Populations Over 10 Million ]example from the MongoDB Aggregation Framework documentation. We added additional sorting to produce stable results with different MongoDB versions. Here we want to return all states with a population greater than 10 million, using the aggregation framework. This example demonstrates the usage of grouping, sorting and matching (filtering). + +[source,java] +---- +class StateStats { + @Id String id; + String state; + @Field("totalPop") int totalPopulation; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +TypedAggregation agg = newAggregation(ZipInfo.class, + group("state").sum("population").as("totalPop"), + sort(ASC, previousOperation(), "totalPop"), + match(where("totalPop").gte(10 * 1000 * 1000)) +); + +AggregationResults result = mongoTemplate.aggregate(agg, StateStats.class); +List stateStatsList = result.getMappedResults(); +---- + +* As a first step we group the input collection by the `"state"` field and calculate the sum of the `"population"` field and store the result in the new field `"totalPop"`. +* In the second step we sort the intermediate result by the id-reference of the previous group operation in addition to the `"totalPop"` field in ascending order. +* Finally in the third step we filter the intermediate result by using a `match` operation which accepts a `Criteria` query as an argument. + +Note that we derive the name of the input-collection from the `ZipInfo`-class passed as first parameter to the `newAggregation`-Method. + +[[mongo.aggregation.examples.example4]] +==== Aggregation Framework Example 4 + +This example demonstrates the use of simple arithmetic operations in the projection operation. + +[source,java] +---- +class Product { + String id; + String name; + double netPrice; + int spaceUnits; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +TypedAggregation agg = newAggregation(Product.class, + project("name", "netPrice") + .and("netPrice").plus(1).as("netPricePlus1") + .and("netPrice").minus(1).as("netPriceMinus1") + .and("netPrice").multiply(1.19).as("grossPrice") + .and("netPrice").divide(2).as("netPriceDiv2") + .and("spaceUnits").mod(2).as("spaceUnitsMod2") +); + +AggregationResults result = mongoTemplate.aggregate(agg, DBObject.class); +List resultList = result.getMappedResults(); +---- + +Note that we derive the name of the input-collection from the `Product`-class passed as first parameter to the `newAggregation`-Method. + +[[mongo.aggregation.examples.example5]] +==== Aggregation Framework Example 5 + +This example demonstrates the use of simple arithmetic operations derived from SpEL Expressions in the projection operation. + +[source,java] +---- +class Product { + String id; + String name; + double netPrice; + int spaceUnits; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +TypedAggregation agg = newAggregation(Product.class, + project("name", "netPrice") + .andExpression("netPrice + 1").as("netPricePlus1") + .andExpression("netPrice - 1").as("netPriceMinus1") + .andExpression("netPrice / 2").as("netPriceDiv2") + .andExpression("netPrice * 1.19").as("grossPrice") + .andExpression("spaceUnits % 2").as("spaceUnitsMod2") + .andExpression("(netPrice * 0.8 + 1.2) * 1.19").as("grossPriceIncludingDiscountAndCharge") + +); + +AggregationResults result = mongoTemplate.aggregate(agg, DBObject.class); +List resultList = result.getMappedResults(); +---- + +[[mongo.aggregation.examples.example6]] +==== Aggregation Framework Example 6 + +This example demonstrates the use of complex arithmetic operations derived from SpEL Expressions in the projection operation. + +Note: The additional parameters passed to the `addExpression` Method can be referenced via indexer expressions according to their position. In this example we reference the parameter which is the first parameter of the parameters array via `[0]`. External parameter expressions are replaced with their respective values when the SpEL expression is transformed into a MongoDB aggregation framework expression. + +[source,java] +---- +class Product { + String id; + String name; + double netPrice; + int spaceUnits; +} +---- + +[source,java] +---- +import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; + +double shippingCosts = 1.2; + +TypedAggregation agg = newAggregation(Product.class, + project("name", "netPrice") + .andExpression("(netPrice * (1-discountRate) + [0]) * (1+taxRate)", shippingCosts).as("salesPrice") +); + +AggregationResults result = mongoTemplate.aggregate(agg, DBObject.class); +List resultList = result.getMappedResults(); +---- + +Note that we can also refer to other fields of the document within the SpEL expression. + +[[mongo.custom-converters]] +== Overriding default mapping with custom converters + +In order to have more fine grained control over the mapping process you can register Spring converters with the `MongoConverter` implementations such as the `MappingMongoConverter`. + +The `MappingMongoConverter` checks to see if there are any Spring converters that can handle a specific class before attempting to map the object itself. To 'hijack' the normal mapping strategies of the `MappingMongoConverter`, perhaps for increased performance or other custom mapping needs, you first need to create an implementation of the Spring `Converter` interface and then register it with the MappingConverter. + +NOTE: For more information on the Spring type conversion service see the reference docs http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert[here]. + +[[mongo.custom-converters.writer]] +=== Saving using a registered Spring Converter + +An example implementation of the `Converter` that converts from a Person object to a `com.mongodb.DBObject` is shown below + +[source,java] +---- +import org.springframework.core.convert.converter.Converter; + +import com.mongodb.BasicDBObject; +import com.mongodb.DBObject; + +public class PersonWriteConverter implements Converter { + + public DBObject convert(Person source) { + DBObject dbo = new BasicDBObject(); + dbo.put("_id", source.getId()); + dbo.put("name", source.getFirstName()); + dbo.put("age", source.getAge()); + return dbo; + } +} +---- + +[[mongo.custom-converters.reader]] +=== Reading using a Spring Converter + +An example implementation of a Converter that converts from a DBObject ot a Person object is shownn below + +[source,java] +---- +public class PersonReadConverter implements Converter { + + public Person convert(DBObject source) { + Person p = new Person((ObjectId) source.get("_id"), (String) source.get("name")); + p.setAge((Integer) source.get("age")); + return p; + } +} +---- + +[[mongo.custom-converters.xml]] +=== Registering Spring Converters with the MongoConverter + +The Mongo Spring namespace provides a convenience way to register Spring `Converter`s with the `MappingMongoConverter`. The configuration snippet below shows how to manually register converter beans as well as configuring the wrapping `MappingMongoConverter` into a `MongoTemplate`. + +[source,xml] +---- + + + + + + + + + + + + + + + + + +---- + +You can also use the base-package attribute of the custom-converters element to enable classpath scanning for all `Converter` and `GenericConverter` implementations below the given package. + +[source,xml] +---- + + + +---- + +[[mongo.converter-disambiguation]] +=== Converter disambiguation + +Generally we inspect the `Converter` implementations for the source and target types they convert from and to. Depending on whether one of those is a type MongoDB can handle natively we will register the converter instance as reading or writing one. Have a look at the following samples: + +[source,java] +---- +// Write converter as only the target type is one Mongo can handle natively +class MyConverter implements Converter { … } + +// Read converter as only the source type is one Mongo can handle natively +class MyConverter implements Converter { … } +---- + +In case you write a `Converter` whose source and target type are native Mongo types there's no way for us to determine whether we should consider it as reading or writing converter. Registering the converter instance as both might lead to unwanted results then. E.g. a `Converter` is ambiguous although it probably does not make sense to try to convert all `String`s into `Long`s when writing. To be generally able to force the infrastructure to register a converter for one way only we provide `@ReadingConverter` as well as `@WritingConverter` to be used at the converter implementation. + +[[mongo-template.index-and-collections]] +== Index and Collection management + +`MongoTemplate` provides a few methods for managing indexes and collections. These are collected into a helper interface called `IndexOperations`. You access these operations by calling the method `indexOps` and pass in either the collection name or the `java.lang.Class` of your entity (the collection name will be derived from the .class either by name or via annotation metadata). + +The `IndexOperations` interface is shown below + +[source,java] +---- +public interface IndexOperations { + + void ensureIndex(IndexDefinition indexDefinition); + + void dropIndex(String name); + + void dropAllIndexes(); + + void resetIndexCache(); + + List getIndexInfo(); +} +---- + +[[mongo-template.index-and-collections.index]] +=== Methods for creating an Index + +We can create an index on a collection to improve query performance. + +==== Creating an index using the MongoTemplate + +[source,java] +---- +mongoTemplate.indexOps(Person.class).ensureIndex(new Index().on("name",Order.ASCENDING)); +---- + +* *ensureIndex* Ensure that an index for the provided IndexDefinition exists for the collection. + +You can create standard, geospatial and text indexes using the classes `IndexDefinition`, `GeoSpatialIndex` and `TextIndexDefinition`. For example, given the Venue class defined in a previous section, you would declare a geospatial query as shown below. + +[source,java] +---- +mongoTemplate.indexOps(Venue.class).ensureIndex(new GeospatialIndex("location")); +---- + +[[mongo-template.index-and-collections.access]] +=== Accessing index information + +The IndexOperations interface has the method getIndexInfo that returns a list of IndexInfo objects. This contains all the indexes defined on the collectcion. Here is an example that defines an index on the Person class that has age property. + +[source,java] +---- +template.indexOps(Person.class).ensureIndex(new Index().on("age", Order.DESCENDING).unique(Duplicates.DROP)); + +List indexInfoList = template.indexOps(Person.class).getIndexInfo(); + +// Contains +// [IndexInfo [fieldSpec={_id=ASCENDING}, name=_id_, unique=false, dropDuplicates=false, sparse=false], +// IndexInfo [fieldSpec={age=DESCENDING}, name=age_-1, unique=true, dropDuplicates=true, sparse=false]] +---- + +[[mongo-template.index-and-collections.collection]] +=== Methods for working with a Collection + +It's time to look at some code examples showing how to use the `MongoTemplate`. First we look at creating our first collection. + +==== Working with collections using the MongoTemplate + +[source,java] +---- +DBCollection collection = null; +if (!mongoTemplate.getCollectionNames().contains("MyNewCollection")) { + collection = mongoTemplate.createCollection("MyNewCollection"); +} + +mongoTemplate.dropCollection("MyNewCollection"); +---- + +* *getCollectionNames* Returns a set of collection names. +* *collectionExists* Check to see if a collection with a given name exists. +* *createCollection* Create an uncapped collection +* *dropCollection* Drop the collection +* *getCollection* Get a collection by name, creating it if it doesn't exist. + +[[mongo-template.commands]] +== Executing Commands + +You can also get at the MongoDB driver's `DB.command( )` method using the `executeCommand(…)` methods on `MongoTemplate`. These will also perform exception translation into Spring's `DataAccessException` hierarchy. + +[[mongo-template.commands.execution]] +=== Methods for executing commands + +* `CommandResult` *executeCommand* `(DBObject command)` Execute a MongoDB command. +* `CommandResult` *executeCommand* `(String jsonCommand)` Execute the a MongoDB command expressed as a JSON string. + +[[mongodb.mapping-usage.events]] +== Lifecycle Events + +Built into the MongoDB mapping framework are several `org.springframework.context.ApplicationEvent` events that your application can respond to by registering special beans in the `ApplicationContext`. By being based off Spring's ApplicationContext event infastructure this enables other products, such as Spring Integration, to easily receive these events as they are a well known eventing mechanism in Spring based applications. + +To intercept an object before it goes through the conversion process (which turns your domain object into a `com.mongodb.DBObject`), you'd register a subclass of `AbstractMongoEventListener` that overrides the `onBeforeConvert` method. When the event is dispatched, your listener will be called and passed the domain object before it goes into the converter. + +[source,java] +---- +public class BeforeConvertListener extends AbstractMongoEventListener { + @Override + public void onBeforeConvert(Person p) { + ... does some auditing manipulation, set timestamps, whatever ... + } +} +---- + +To intercept an object before it goes into the database, you'd register a subclass of `org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener` that overrides the `onBeforeSave` method. When the event is dispatched, your listener will be called and passed the domain object and the converted `com.mongodb.DBObject`. + +[source,java] +---- +public class BeforeSaveListener extends AbstractMongoEventListener { + @Override + public void onBeforeSave(Person p, DBObject dbo) { + … change values, delete them, whatever … + } +} +---- + +Simply declaring these beans in your Spring ApplicationContext will cause them to be invoked whenever the event is dispatched. + +The list of callback methods that are present in AbstractMappingEventListener are + +* `onBeforeConvert` - called in MongoTemplate insert, insertList and save operations before the object is converted to a DBObject using a MongoConveter. +* `onBeforeSave` - called in MongoTemplate insert, insertList and save operations *before* inserting/saving the DBObject in the database. +* `onAfterSave` - called in MongoTemplate insert, insertList and save operations *after* inserting/saving the DBObject in the database. +* `onAfterLoad` - called in MongoTemplate find, findAndRemove, findOne and getCollection methods after the DBObject is retrieved from the database. +* `onAfterConvert` - called in MongoTemplate find, findAndRemove, findOne and getCollection methods after the DBObject retrieved from the database was converted to a POJO. + +[[mongo.exception]] +== Exception Translation + +The Spring framework provides exception translation for a wide variety of database and mapping technologies. This has traditionally been for JDBC and JPA. The Spring support for MongoDB extends this feature to the MongoDB Database by providing an implementation of the `org.springframework.dao.support.PersistenceExceptionTranslator` interface. + +The motivation behind mapping to Spring's http://docs.spring.io/spring/docs/current/spring-framework-reference/html/dao.html#dao-exceptions[consistent data access exception hierarchy] is that you are then able to write portable and descriptive exception handling code without resorting to coding against http://www.mongodb.org/about/contributors/error-codes/[MongoDB error codes]. All of Spring's data access exceptions are inherited from the root `DataAccessException` class so you can be sure that you will be able to catch all database related exception within a single try-catch block. Note, that not all exceptions thrown by the MongoDB driver inherit from the MongoException class. The inner exception and message are preserved so no information is lost. + +Some of the mappings performed by the `MongoExceptionTranslator` are: com.mongodb.Network to DataAccessResourceFailureException and `MongoException` error codes 1003, 12001, 12010, 12011, 12012 to `InvalidDataAccessApiUsageException`. Look into the implementation for more details on the mapping. + +[[mongo.executioncallback]] +== Execution callbacks + +One common design feature of all Spring template classes is that all functionality is routed into one of the templates execute callback methods. This helps ensure that exceptions and any resource management that maybe required are performed consistency. While this was of much greater need in the case of JDBC and JMS than with MongoDB, it still offers a single spot for exception translation and logging to occur. As such, using thexe execute callback is the preferred way to access the MongoDB driver's `DB` and `DBCollection` objects to perform uncommon operations that were not exposed as methods on `MongoTemplate`. + +Here is a list of execute callback methods. + +* ` T` *execute* `(Class entityClass, CollectionCallback action)` Executes the given CollectionCallback for the entity collection of the specified class. + +* ` T` *execute* `(String collectionName, CollectionCallback action)` Executes the given CollectionCallback on the collection of the given name. + +* ` T` *execute* `(DbCallback action) Spring Data MongoDB provides support for the Aggregation Framework introduced to MongoDB in version 2.2.` Executes a DbCallback translating any exceptions as necessary. + +* ` T` *execute* `(String collectionName, DbCallback action)` Executes a DbCallback on the collection of the given name translating any exceptions as necessary. + +* ` T` *executeInSession* `(DbCallback action) ` Executes the given DbCallback within the same connection to the database so as to ensure consistency in a write heavy environment where you may read the data that you wrote. + +Here is an example that uses the `CollectionCallback` to return information about an index + +[source,java] +---- +boolean hasIndex = template.execute("geolocation", new CollectionCallbackBoolean>() { + public Boolean doInCollection(Venue.class, DBCollection collection) throws MongoException, DataAccessException { + List indexes = collection.getIndexInfo(); + for (DBObject dbo : indexes) { + if ("location_2d".equals(dbo.get("name"))) { + return true; + } + } + return false; + } +}); +---- + +[[gridfs]] +== GridFS support + +MongoDB supports storing binary files inside it's filesystem GridFS. Spring Data MongoDB provides a `GridFsOperations` interface as well as the according implementation `GridFsTemplate` to easily interact with the filesystem. You can setup a `GridFsTemplate` instance by handing it a `MongoDbFactory` as well as a `MongoConverter`: + +=== JavaConfig setup for a GridFsTemplate + +[source,java] +---- +class GridFsConfiguration extends AbstractMongoConfiguration { + + // … further configuration omitted + + @Bean + public GridFsTemplate gridFsTemplate() { + return new GridFsTemplate(mongoDbFactory(), mappingMongoConverter()); + } +} +---- + +An according XML configuration looks like this: + +=== XML configuration for a GridFsTemplate + +[source,xml] +---- + + + + + + + + + + + + +---- + +The template can now be injected and used to perform storage and retrieval operations. + +=== Using GridFsTemplate to store files + +[source,java] +---- +class GridFsClient { + + @Autowired + GridFsOperations operations; + + @Test + public void storeFileToGridFs { + + FileMetadata metadata = new FileMetadata(); + // populate metadata + Resource file = … // lookup File or Resource + + operations.store(file.getInputStream(), "filename.txt", metadata); + } +} +---- + +The `store(…)` operations take an `InputStream`, a filename and optionally metadata information about the file to store. The metadata can be an arbitrary object which will be marshalled by the `MongoConverter` configured with the `GridFsTemplate`. Alternatively you can also provide a `DBObject` as well. + +Reading files from the filesystem can either be achieved through the `find(…)` or `getResources(…)` methods. Let's have a look at the `find(…)` methods first. You can either find a single file matching a `Query` or multiple ones. To easily define file queries we provide the `GridFsCriteria` helper class. It provides static factory methods to encapsulate default metadata fields (e.g. `whereFilename()`, `whereContentType()`) or the custom one through `whereMetaData()`. + +=== Using GridFsTemplate to query for files + +[source,java] +---- +class GridFsClient { + + @Autowired + GridFsOperations operations; + + @Test + public void findFilesInGridFs { + List result = operations.find(query(whereFilename().is("filename.txt"))) + } +} +---- + +NOTE: Currently MongoDB does not support defining sort criteria when retrieving files from GridFS. Thus any sort criteria defined on the `Query` instance handed into the `find(…)` method will be disregarded. + +The other option to read files from the GridFs is using the methods introduced by the `ResourcePatternResolver` interface. They allow handing an Ant path into the method ar thus retrieve files matching the given pattern. + +=== Using GridFsTemplate to read files + +[source,java] +---- +class GridFsClient { + + @Autowired + GridFsOperations operations; + + @Test + public void readFilesFromGridFs { + GridFsResources[] txtFiles = operations.getResources("*.txt"); + } +} +---- + +`GridFsOperations` extending `ResourcePatternResolver` allows the `GridFsTemplate` e.g. to be plugged into an `ApplicationContext` to read Spring Config files from a MongoDB.