DATAMONGO-701 - Improve performance of starts-with and ends-with queries.

This changes the starts-with regex to the prefixed form using ^ to better make use of any index on the queried field. Also changes ending-with queries to use the $ anchor.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java

@@ -269,10 +269,10 @@ class MongoQueryCreator extends AbstractQueryCreator<Query, Criteria> {
 
 		switch (type) {
 			case STARTING_WITH:
-				source = source + "*";
+				source = "^" + source;
 				break;
 			case ENDING_WITH:
-				source = "*" + source;
+				source = source + "$";
 				break;
 			case CONTAINING:
 				source = "*" + source + "*";

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/AbstractPersonRepositoryIntegrationTests.java

@@ -53,11 +53,9 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 @RunWith(SpringJUnit4ClassRunner.class)
 public abstract class AbstractPersonRepositoryIntegrationTests {
 
-	@Autowired
-	protected PersonRepository repository;
+	@Autowired protected PersonRepository repository;
 
-	@Autowired
-	MongoOperations operations;
+	@Autowired MongoOperations operations;
 
 	Person dave, oliver, carter, boyd, stefan, leroi, alicia;
 	QPerson person;
@@ -570,4 +568,26 @@ public abstract class AbstractPersonRepositoryIntegrationTests {
 	public void executesAnnotatedCountProjection() {
 		assertThat(repository.someCountQuery("Matthews"), is(2L));
 	}
+
+	/**
+	 * @see DATAMONGO-701
+	 */
+	@Test
+	public void executesDerivedStartsWithQueryCorrectly() {
+
+		List<Person> result = repository.findByLastnameStartsWith("Matt");
+		assertThat(result, hasSize(2));
+		assertThat(result, hasItems(dave, oliver));
+	}
+
+	/**
+	 * @see DATAMONGO-701
+	 */
+	@Test
+	public void executesDerivedEndsWithQueryCorrectly() {
+
+		List<Person> result = repository.findByLastnameEndsWith("thews");
+		assertThat(result, hasSize(2));
+		assertThat(result, hasItems(dave, oliver));
+	}
 }

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/PersonRepository.java

@@ -47,6 +47,10 @@ public interface PersonRepository extends MongoRepository<Person, String>, Query
 	 */
 	List<Person> findByLastname(String lastname);
 
+	List<Person> findByLastnameStartsWith(String prefix);
+
+	List<Person> findByLastnameEndsWith(String postfix);
+
 	/**
 	 * Returns all {@link Person}s with the given lastname ordered by their firstname.
 	 * 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/MongoQueryCreatorUnitTests.java

@@ -263,7 +263,7 @@ public class MongoQueryCreatorUnitTests {
 		MongoQueryCreator creator = new MongoQueryCreator(tree, getAccessor(converter, "Matt"), context);
 		Query query = creator.createQuery();
 
-		assertThat(query, is(query(where("foo").regex("Matt.*"))));
+		assertThat(query, is(query(where("foo").regex("^Matt"))));
 	}
 
 	/**
@@ -276,7 +276,7 @@ public class MongoQueryCreatorUnitTests {
 		MongoQueryCreator creator = new MongoQueryCreator(tree, getAccessor(converter, "ews"), context);
 		Query query = creator.createQuery();
 
-		assertThat(query, is(query(where("foo").regex(".*ews"))));
+		assertThat(query, is(query(where("foo").regex("ews$"))));
 	}
 
 	/**