DATAJPA-464 - Add support for returning subtypes of Repository Entity in JpaRepository.saveAndFlush.

Adopted generic method declaration from save method to saveAndFlush.

Original pull request: #58.

src/main/java/org/springframework/data/jpa/repository/JpaRepository.java

@@ -67,7 +67,7 @@ public interface JpaRepository<T, ID extends Serializable> extends PagingAndSort
 	 * @param entity
 	 * @return the saved entity
 	 */
-	T saveAndFlush(T entity);
+	<S extends T> S saveAndFlush(S entity);
 
 	/**
 	 * Deletes the given entities in a batch which means it will create a single {@link Query}. Assume that we will clear

src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

@@ -378,9 +378,9 @@ public class SimpleJpaRepository<T, ID extends Serializable> implements JpaRepos
 	 * @see org.springframework.data.jpa.repository.JpaRepository#saveAndFlush(java.lang.Object)
 	 */
 	@Transactional
-	public T saveAndFlush(T entity) {
+	public <S extends T> S saveAndFlush(S entity) {
 
-		T result = save(entity);
+		S result = save(entity);
 		flush();
 
 		return result;

src/test/java/org/springframework/data/jpa/repository/UserRepositoryTests.java

@@ -55,6 +55,7 @@ import org.springframework.data.domain.Sort.Order;
 import org.springframework.data.jpa.domain.Specification;
 import org.springframework.data.jpa.domain.sample.Address;
 import org.springframework.data.jpa.domain.sample.Role;
+import org.springframework.data.jpa.domain.sample.SpecialUser;
 import org.springframework.data.jpa.domain.sample.User;
 import org.springframework.data.jpa.repository.sample.UserRepository;
 import org.springframework.test.context.ContextConfiguration;
@@ -1213,7 +1214,7 @@ public class UserRepositoryTests {
 	}
 
 	/**
-	 * @DATAJPA-461
+	 * @see DATAJPA-461
 	 */
 	@Test
 	public void customFindByQueryWithPositionalVarargsParameters() {
@@ -1227,7 +1228,7 @@ public class UserRepositoryTests {
 	}
 
 	/**
-	 * @DATAJPA-461
+	 * @see DATAJPA-461
 	 */
 	@Test
 	public void customFindByQueryWithNamedVarargsParameters() {
@@ -1240,6 +1241,23 @@ public class UserRepositoryTests {
 		assertThat(result, hasItems(firstUser, secondUser));
 	}
 
+	/**
+	 * @see DATAJPA-464
+	 */
+	@Test
+	public void saveAndFlushShouldSupportReturningSubTypesOfRepositoryEntity() {
+
+		repository.deleteAll();
+		SpecialUser user = new SpecialUser();
+		user.setFirstname("Thomas");
+		user.setEmailAddress("thomas@example.org");
+
+		SpecialUser savedUser = repository.saveAndFlush(user);
+
+		assertThat(user.getFirstname(), is(savedUser.getFirstname()));
+		assertThat(user.getEmailAddress(), is(savedUser.getEmailAddress()));
+	}
+
 	private Page<User> executeSpecWithSort(Sort sort) {
 
 		flushTestUsers();