DATAMONGO-1454 - Derive string query count projection from return type.

Author: mp911de

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

@@ -200,6 +200,17 @@ public boolean isExistsQuery() {
 		return unwrappedReturnType.isAssignableFrom(Boolean.class) || unwrappedReturnType.isAssignableFrom(Boolean.TYPE);
 	}
 
+	/**
+	 * Returns whether the query is a count projection by checking the return type.
+	 *
+	 * @return
+	 * @since 1.10
+	 */
+	public boolean isCountQuery() {
+		return unwrappedReturnType.isAssignableFrom(Long.class) || unwrappedReturnType.isAssignableFrom(Long.TYPE)
+				|| unwrappedReturnType.isAssignableFrom(Number.class);
+	}
+
 	/**
 	 * Returns the {@link Query} annotation that is applied to the method or {@code null} if none available.
 	 * 

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

@@ -97,7 +97,7 @@ public StringBasedMongoQuery(String query, MongoQueryMethod method, MongoOperati
 		this.fieldSpec = BINDING_PARSER.parseAndCollectParameterBindingsFromQueryIntoBindings(
 				method.getFieldSpecification(), this.fieldSpecParameterBindings);
 
-		this.isCountQuery = method.hasAnnotatedQuery() && method.getQueryAnnotation().count();
+		this.isCountQuery = method.isCountQuery() || (method.hasAnnotatedQuery() && method.getQueryAnnotation().count());
 		this.isExistsQuery = method.isExistsQuery();
 		this.isDeleteQuery = method.hasAnnotatedQuery() && method.getQueryAnnotation().delete();
 

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

@@ -235,6 +235,17 @@ public void createsMongoQueryMethodWithWrappedExistsProjection() throws Exceptio
 		assertThat(method.isExistsQuery(), is(true));
 	}
 
+	/**
+	 * @see DATAMONGO-1454
+	 */
+	@Test
+	public void createsMongoQueryMethodWithCountProjection() throws Exception {
+
+		MongoQueryMethod method = queryMethod(PersonRepository.class, "countBy");
+
+		assertThat(method.isCountQuery(), is(true));
+	}
+
 	private MongoQueryMethod queryMethod(Class<?> repository, String name, Class<?>... parameters) throws Exception {
 
 		Method method = repository.getMethod(name, parameters);
@@ -281,6 +292,8 @@ interface PersonRepository extends Repository<User, Long> {
 		boolean existsBy();
 
 		Future<Boolean> existsByFuture();
+
+		Integer countBy();
 	}
 
 	interface SampleRepository extends Repository<Contact, Long> {

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

@@ -373,6 +373,16 @@ public void shouldSupportExistsProjection() throws Exception {
 		assertThat(mongoQuery.isExistsQuery(), is(true));
 	}
 
+	/**
+	 * @see DATAMONGO-1454
+	 */
+	@Test
+	public void shouldDeriveCountProjectionFromReturnType() throws Exception {
+
+		assertThat(createQueryForMethod("countMethod", String.class).isCountQuery(), is(true));
+		assertThat(createQueryForMethod("countNumberMethod", String.class).isCountQuery(), is(true));
+	}
+
 	private StringBasedMongoQuery createQueryForMethod(String name, Class<?>... parameters) throws Exception {
 
 		Method method = SampleRepository.class.getMethod(name, parameters);
@@ -408,6 +418,12 @@ private interface SampleRepository extends Repository<Person, Long> {
 		@Query(value = "{ 'lastname' : ?0 }", delete = true, count = true)
 		void invalidMethod(String lastname);
 
+		@Query(value = "{ 'lastname' : ?0 }")
+		long countMethod(String lastname);
+
+		@Query(value = "{ 'lastname' : ?0 }")
+		Number countNumberMethod(String lastname);
+
 		@Query(value = "?0", fields = "?1")
 		DBObject findByParameterizedCriteriaAndFields(DBObject criteria, Map<String, Integer> fields);