DATACMNS-483 - Added test case for recursive object wrapper resolution.

AbstractRepositoryMetadata now correctly resolves the domain type in case it's nested in multiple levels of wrapper types.

Author: odrotbohm

src/main/java/org/springframework/data/repository/core/support/AbstractRepositoryMetadata.java

@@ -57,14 +57,7 @@ public AbstractRepositoryMetadata(Class<?> repositoryInterface) {
 	 * @see org.springframework.data.repository.core.RepositoryMetadata#getReturnedDomainClass(java.lang.reflect.Method)
 	 */
 	public Class<?> getReturnedDomainClass(Method method) {
-
-		TypeInformation<?> returnTypeInfo = typeInformation.getReturnType(method);
-		Class<?> rawType = returnTypeInfo.getType();
-
-		boolean needToUnwrap = Iterable.class.isAssignableFrom(rawType) || rawType.isArray()
-				|| QueryExecutionConverters.supports(rawType);
-
-		return needToUnwrap ? returnTypeInfo.getComponentType().getType() : rawType;
+		return unwrapWrapperTypes(typeInformation.getReturnType(method));
 	}
 
 	/* 
@@ -104,4 +97,20 @@ public boolean isPagingRepository() {
 
 		return Arrays.asList(findAllMethod.getParameterTypes()).contains(Pageable.class);
 	}
+
+	/**
+	 * Recursively unwraps well known wrapper types from the given {@link TypeInformation}.
+	 * 
+	 * @param type must not be {@literal null}.
+	 * @return
+	 */
+	private static Class<?> unwrapWrapperTypes(TypeInformation<?> type) {
+
+		Class<?> rawType = type.getType();
+
+		boolean needToUnwrap = Iterable.class.isAssignableFrom(rawType) || rawType.isArray()
+				|| QueryExecutionConverters.supports(rawType);
+
+		return needToUnwrap ? unwrapWrapperTypes(type.getComponentType()) : rawType;
+	}
 }

src/test/java/org/springframework/data/repository/core/support/DefaultRepositoryMetadataUnitTests.java

@@ -117,6 +117,18 @@ public void discoversDomainTypeOnReturnTypeWrapper() throws Exception {
 		assertThat(metadata.getReturnedDomainClass(method), is(typeCompatibleWith(User.class)));
 	}
 
+	/**
+	 * @see DATACMNS-483
+	 */
+	@Test
+	public void discoversDomainTypeOnNestedReturnTypeWrapper() throws Exception {
+
+		RepositoryMetadata metadata = new DefaultRepositoryMetadata(OptionalRepository.class);
+
+		Method method = OptionalRepository.class.getMethod("findByLastname", String.class);
+		assertThat(metadata.getReturnedDomainClass(method), is(typeCompatibleWith(User.class)));
+	}
+
 	@SuppressWarnings("unused")
 	private class User {
 
@@ -187,5 +199,8 @@ static interface ConcreteRepository extends IdTypeFixingRepository<User> {
 	static interface OptionalRepository extends Repository<User, Long> {
 
 		Optional<User> findByEmailAddress(String emailAddress);
+
+		// Contrived example but to make sure recursive wrapper resolution works
+		Optional<Optional<User>> findByLastname(String lastname);
 	}
 }