Introduce factory methods for MongoDatabaseFactory for client lifecycle guidance.

We now expose create(…) methods returning either MongoDatabaseFactory when created with a client that doesn't publicly declare a destroy() method and create methods returning SimpleMongoClientDatabaseFactory when used with a connection string to indicate lifecycle-awareness for the internally created MongoClient.

See #5012

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoDatabaseFactory.java

@@ -16,12 +16,17 @@
 package org.springframework.data.mongodb;
 
 import org.bson.codecs.configuration.CodecRegistry;
+
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mongodb.core.MongoExceptionTranslator;
+import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
+import org.springframework.util.Assert;
 
 import com.mongodb.ClientSessionOptions;
+import com.mongodb.ConnectionString;
 import com.mongodb.client.ClientSession;
+import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoDatabase;
 
 /**
@@ -30,10 +35,56 @@ import com.mongodb.client.MongoDatabase;
  * @author Mark Pollack
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @since 3.0
  */
 public interface MongoDatabaseFactory extends CodecRegistryProvider, MongoSessionProvider {
 
+	/**
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance for the given {@code connectionString}. Using this
+	 * factory method will create a new {@link MongoClient} instance that will be closed when calling
+	 * {@link SimpleMongoClientDatabaseFactory#destroy()}.
+	 *
+	 * @param connectionString connection coordinates for a database connection. Must contain a database name and must not
+	 *          be {@literal null} or empty.
+	 * @since 4.5.2
+	 * @see <a href="https://docs.mongodb.com/manual/reference/connection-string/">MongoDB Connection String reference</a>
+	 */
+	static SimpleMongoClientDatabaseFactory create(String connectionString) {
+
+		Assert.notNull(connectionString, "ConnectionString must not be null");
+
+		return new SimpleMongoClientDatabaseFactory(connectionString);
+	}
+
+	/**
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance from the given {@link MongoClient}. Using this
+	 * factory will create a new {@link MongoClient} instance that will be closed when calling
+	 * {@link SimpleMongoClientDatabaseFactory#destroy()}.
+	 *
+	 * @param connectionString connection coordinates for a database connection. Must contain also a database name and not
+	 *          be {@literal null}.
+	 * @since 4.5.2
+	 */
+	static SimpleMongoClientDatabaseFactory create(ConnectionString connectionString) {
+
+		Assert.notNull(connectionString, "ConnectionString must not be null");
+
+		return new SimpleMongoClientDatabaseFactory(connectionString);
+	}
+
+	/**
+	 * Creates a new {@link MongoDatabaseFactory} instance from the given {@link MongoClient}. We assume a managed client
+	 * instance that will be disposed by you (or the application container) once the client is no longer required for use.
+	 *
+	 * @param mongoClient must not be {@literal null}.
+	 * @param databaseName must not be {@literal null} or empty.
+	 * @since 4.5.2
+	 */
+	static MongoDatabaseFactory create(MongoClient mongoClient, String databaseName) {
+		return new SimpleMongoClientDatabaseFactory(mongoClient, databaseName);
+	}
+
 	/**
 	 * Obtain a {@link MongoDatabase} from the underlying factory.
 	 *

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoSessionProvider.java

@@ -31,7 +31,7 @@ import com.mongodb.client.ClientSession;
 public interface MongoSessionProvider {
 
 	/**
-	 * Obtain a {@link ClientSession} with with given options.
+	 * Obtain a {@link ClientSession} with given options.
 	 *
 	 * @param options must not be {@literal null}.
 	 * @return never {@literal null}.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/ReactiveMongoDatabaseFactory.java

@@ -18,12 +18,17 @@ package org.springframework.data.mongodb;
 import reactor.core.publisher.Mono;
 
 import org.bson.codecs.configuration.CodecRegistry;
+
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mongodb.core.MongoExceptionTranslator;
+import org.springframework.data.mongodb.core.SimpleReactiveMongoDatabaseFactory;
+import org.springframework.util.Assert;
 
 import com.mongodb.ClientSessionOptions;
+import com.mongodb.ConnectionString;
 import com.mongodb.reactivestreams.client.ClientSession;
+import com.mongodb.reactivestreams.client.MongoClient;
 import com.mongodb.reactivestreams.client.MongoDatabase;
 
 /**
@@ -36,6 +41,51 @@ import com.mongodb.reactivestreams.client.MongoDatabase;
  */
 public interface ReactiveMongoDatabaseFactory extends CodecRegistryProvider {
 
+	/**
+	 * Creates a new {@link SimpleReactiveMongoDatabaseFactory} instance for the given {@code connectionString}. Using
+	 * this factory method will create a new {@link MongoClient} instance that will be closed when calling
+	 * {@link SimpleReactiveMongoDatabaseFactory#destroy()}.
+	 *
+	 * @param connectionString connection coordinates for a database connection. Must contain a database name and must not
+	 *          be {@literal null} or empty.
+	 * @since 4.5.2
+	 * @see <a href="https://docs.mongodb.com/manual/reference/connection-string/">MongoDB Connection String reference</a>
+	 */
+	static SimpleReactiveMongoDatabaseFactory create(String connectionString) {
+
+		Assert.notNull(connectionString, "ConnectionString must not be null");
+
+		return create(new ConnectionString(connectionString));
+	}
+
+	/**
+	 * Creates a new {@link SimpleReactiveMongoDatabaseFactory} instance from the given {@link MongoClient}. Using this
+	 * factory will create a new {@link MongoClient} instance that will be closed when calling
+	 * {@link SimpleReactiveMongoDatabaseFactory#destroy()}.
+	 *
+	 * @param connectionString connection coordinates for a database connection. Must contain also a database name and not
+	 *          be {@literal null}.
+	 * @since 4.5.2
+	 */
+	static SimpleReactiveMongoDatabaseFactory create(ConnectionString connectionString) {
+
+		Assert.notNull(connectionString, "ConnectionString must not be null");
+
+		return new SimpleReactiveMongoDatabaseFactory(connectionString);
+	}
+
+	/**
+	 * Creates a new {@link MongoDatabaseFactory} instance from the given {@link MongoClient}. We assume a managed client
+	 * instance that will be disposed by you (or the application container) once the client is no longer required for use.
+	 *
+	 * @param mongoClient must not be {@literal null}.
+	 * @param databaseName must not be {@literal null} or empty.
+	 * @since 4.5.2
+	 */
+	static ReactiveMongoDatabaseFactory create(MongoClient mongoClient, String databaseName) {
+		return new SimpleReactiveMongoDatabaseFactory(mongoClient, databaseName);
+	}
+
 	/**
 	 * Creates a default {@link MongoDatabase} instance.
 	 *

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoClientConfiguration.java

@@ -20,7 +20,6 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.SpringDataMongoDB;
 import org.springframework.data.mongodb.core.MongoTemplate;
-import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.DbRefResolver;
 import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
@@ -75,7 +74,7 @@ public abstract class AbstractMongoClientConfiguration extends MongoConfiguratio
 	 */
 	@Bean
 	public MongoDatabaseFactory mongoDbFactory() {
-		return new SimpleMongoClientDatabaseFactory(mongoClient(), getDatabaseName());
+		return MongoDatabaseFactory.create(mongoClient(), getDatabaseName());
 	}
 
 	/**

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractReactiveMongoConfiguration.java

@@ -21,7 +21,6 @@ import org.springframework.data.mongodb.ReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.SpringDataMongoDB;
 import org.springframework.data.mongodb.core.ReactiveMongoOperations;
 import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
-import org.springframework.data.mongodb.core.SimpleReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
 import org.springframework.data.mongodb.core.convert.NoOpDbRefResolver;
@@ -79,7 +78,7 @@ public abstract class AbstractReactiveMongoConfiguration extends MongoConfigurat
 	 */
 	@Bean
 	public ReactiveMongoDatabaseFactory reactiveMongoDbFactory() {
-		return new SimpleReactiveMongoDatabaseFactory(reactiveMongoClient(), getDatabaseName());
+		return ReactiveMongoDatabaseFactory.create(reactiveMongoClient(), getDatabaseName());
 	}
 
 	/**

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/SimpleMongoClientDatabaseFactoryUnitTests.java

@@ -72,7 +72,7 @@ class SimpleMongoClientDatabaseFactoryUnitTests {
 
 		ConnectionString mongoURI = new ConnectionString(
 				"mongodb://myUsername:myPassword@localhost/myDatabase.myCollection");
-		MongoDatabaseFactory mongoDbFactory = new SimpleMongoClientDatabaseFactory(mongoURI);
+		SimpleMongoClientDatabaseFactory mongoDbFactory = MongoDatabaseFactory.create(mongoURI);
 
 		assertThat(mongoDbFactory).hasFieldOrPropertyWithValue("databaseName", "myDatabase");
 	}
@@ -82,7 +82,7 @@ class SimpleMongoClientDatabaseFactoryUnitTests {
 
 		ConnectionString uri = new ConnectionString(
 				"mongodb://myUserName:myPassWord@127.0.0.1:27017/myDataBase.myCollection");
-		SimpleMongoClientDatabaseFactory factory = new SimpleMongoClientDatabaseFactory(uri);
+		SimpleMongoClientDatabaseFactory factory = MongoDatabaseFactory.create(uri);
 
 		assertThat(factory).hasFieldOrPropertyWithValue("databaseName", "myDataBase");
 	}
@@ -92,7 +92,7 @@ class SimpleMongoClientDatabaseFactoryUnitTests {
 
 		when(mongo.getDatabase("foo")).thenReturn(database);
 
-		MongoDatabaseFactory factory = new SimpleMongoClientDatabaseFactory(mongo, "foo");
+		MongoDatabaseFactory factory = MongoDatabaseFactory.create(mongo, "foo");
 		MongoDatabaseFactory wrapped = factory.withSession(clientSession).withSession(clientSession);
 
 		InvocationHandler invocationHandler = Proxy.getInvocationHandler(wrapped.getMongoDatabase());

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/observability/TestConfig.java

@@ -15,6 +15,13 @@
  */
 package org.springframework.data.mongodb.observability;
 
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.observation.DefaultMeterObservationHandler;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import io.micrometer.observation.ObservationRegistry;
+import io.micrometer.tracing.Tracer;
+import io.micrometer.tracing.test.simple.SimpleTracer;
+
 import java.util.Properties;
 
 import org.springframework.beans.factory.config.PropertiesFactoryBean;
@@ -27,8 +34,6 @@ import org.springframework.data.mongodb.core.MongoOperations;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.ReactiveMongoOperations;
 import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
-import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
-import org.springframework.data.mongodb.core.SimpleReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
@@ -43,15 +48,9 @@ import org.springframework.data.repository.core.support.PropertiesBasedNamedQuer
 
 import com.mongodb.ConnectionString;
 import com.mongodb.MongoClientSettings;
+import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoClients;
 
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.observation.DefaultMeterObservationHandler;
-import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
-import io.micrometer.observation.ObservationRegistry;
-import io.micrometer.tracing.Tracer;
-import io.micrometer.tracing.test.simple.SimpleTracer;
-
 /**
  * @author Mark Paluch
  */
@@ -66,13 +65,23 @@ class TestConfig {
 	}
 
 	@Bean
-	MongoDatabaseFactory mongoDatabaseFactory(MongoClientSettings settings) {
+	MongoClient mongoClient(MongoClientSettings settings) {
-		return new SimpleMongoClientDatabaseFactory(MongoClients.create(settings), "observable");
+		return MongoClients.create(settings);
+	}
+
+	@Bean
+	MongoDatabaseFactory mongoDatabaseFactory(MongoClient client) {
+		return MongoDatabaseFactory.create(client, "observable");
 	}
 
 	@Bean
-	ReactiveMongoDatabaseFactory reactiveMongoDatabaseFactory(MongoClientSettings settings) {
+	com.mongodb.reactivestreams.client.MongoClient reactiveMongoClient(MongoClientSettings settings) {
-		return new SimpleReactiveMongoDatabaseFactory(com.mongodb.reactivestreams.client.MongoClients.create(settings),
+		return com.mongodb.reactivestreams.client.MongoClients.create(settings);
+	}
+
+	@Bean
+	ReactiveMongoDatabaseFactory reactiveMongoDatabaseFactory(com.mongodb.reactivestreams.client.MongoClient client) {
+		return ReactiveMongoDatabaseFactory.create(client,
 				"observable");
 	}
 
@@ -103,17 +112,13 @@ class TestConfig {
 
 	@Bean
 	MongoTemplate mongoTemplate(MongoDatabaseFactory mongoDatabaseFactory, MongoConverter mongoConverter) {
-
+		return new MongoTemplate(mongoDatabaseFactory, mongoConverter);
-		MongoTemplate template = new MongoTemplate(mongoDatabaseFactory, mongoConverter);
-		return template;
 	}
 
 	@Bean
 	ReactiveMongoTemplate reactiveMongoTemplate(ReactiveMongoDatabaseFactory mongoDatabaseFactory,
 			MongoConverter mongoConverter) {
-
+		return new ReactiveMongoTemplate(mongoDatabaseFactory, mongoConverter);
-		ReactiveMongoTemplate template = new ReactiveMongoTemplate(mongoDatabaseFactory, mongoConverter);
-		return template;
 	}
 
 	@Bean