DATAJPA-86 - Pagination over queries using group-by works correctly.

Added handling of count methods for queries using group by. In case the count query returns multiple results we use the number of results instead of failing. If the result contains one result we use this one.

Moved hint handling to AbstractJpaQuery.

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

@@ -725,6 +725,18 @@ public class UserRepositoryTests {
 		assertThat(result, hasItem(firstUser));
 	}
 
+	/**
+	 * @see DATADOC-86
+	 */
+	@Test
+	public void readsPageWithGroupByClauseCorrectly() {
+
+		flushTestUsers();
+
+		Page<String> result = repository.findByLastnameGrouped(new PageRequest(0, 10));
+		assertThat(result.getTotalPages(), is(1));
+	}
+
 	private Page<User> executeSpecWithSort(Sort sort) {
 
 		flushTestUsers();

src/test/java/org/springframework/data/jpa/repository/query/JpaQueryExecutionUnitTests.java

@@ -30,7 +30,7 @@ import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.data.jpa.repository.query.JpaQueryExecution.ModifyingExecution;
 
 /**
- * Unit test for {@link QueryExecution}.
+ * Unit test for {@link JpaQueryExecution}.
  * 
  * @author Oliver Gierke
  */

src/test/java/org/springframework/data/jpa/repository/query/SimpleJpaQueryUnitTests.java

@@ -23,8 +23,7 @@ import static org.mockito.Mockito.*;
 import java.lang.reflect.Method;
 
 import javax.persistence.EntityManager;
-import javax.persistence.Query;
-import javax.persistence.QueryHint;
+import javax.persistence.TypedQuery;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -34,7 +33,6 @@ import org.mockito.Mockito;
 import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
-import org.springframework.data.jpa.repository.QueryHints;
 import org.springframework.data.jpa.repository.sample.UserRepository;
 import org.springframework.data.repository.core.RepositoryMetadata;
 import org.springframework.data.repository.query.Parameters;
@@ -54,31 +52,22 @@ public class SimpleJpaQueryUnitTests {
 	@Mock
 	QueryExtractor extractor;
 	@Mock
-	Query query;
+	TypedQuery<Long> query;
 	@Mock
 	RepositoryMetadata metadata;
 	@Mock
 	ParameterBinder binder;
 
 	@Before
-	@QueryHints(@QueryHint(name = "foo", value = "bar"))
 	public void setUp() throws SecurityException, NoSuchMethodException {
 
 		when(em.createQuery(anyString())).thenReturn(query);
+		when(em.createQuery(anyString(), eq(Long.class))).thenReturn(query);
 
 		Method setUp = UserRepository.class.getMethod("findByLastname", String.class);
 		method = new JpaQueryMethod(setUp, metadata, extractor);
 	}
 
-	@Test
-	public void appliesHintsCorrectly() throws Exception {
-
-		SimpleJpaQuery jpaQuery = new SimpleJpaQuery(method, em, "foobar");
-		jpaQuery.createQuery(new Object[] { "gierke" });
-
-		verify(query).setHint("foo", "bar");
-	}
-
 	@Test
 	public void prefersDeclaredCountQueryOverCreatingOne() throws Exception {
 
@@ -86,7 +75,7 @@ public class SimpleJpaQueryUnitTests {
 		when(method.getCountQuery()).thenReturn("foo");
 		when(method.getParameters()).thenReturn(
 				new Parameters(SimpleJpaQueryUnitTests.class.getMethod("prefersDeclaredCountQueryOverCreatingOne")));
-		when(em.createQuery("foo")).thenReturn(query);
+		when(em.createQuery("foo", Long.class)).thenReturn(query);
 
 		SimpleJpaQuery jpaQuery = new SimpleJpaQuery(method, em, "select u from User u");
 

src/test/java/org/springframework/data/jpa/repository/sample/UserRepository.java

@@ -185,4 +185,9 @@ public interface UserRepository extends JpaRepository<User, Integer>, JpaSpecifi
 
 	List<User> findByLastnameAndFirstnameAllIgnoringCase(String lastname, String firstname);
 
+	/**
+	 * @see DATADOC-86 - Count execution for group by
+	 */
+	@Query("select u.lastname from User u group by u.lastname")
+	Page<String> findByLastnameGrouped(Pageable pageable);
 }