HHH-12670 - Allows native SQL queries that take a given resultClass to map the result set to the required type

hibernate-core/src/main/java/org/hibernate/internal/AbstractSharedSessionContract.java

@@ -10,6 +10,7 @@ import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
+import java.lang.reflect.Array;
 import java.sql.SQLException;
 import java.util.List;
 import java.util.TimeZone;
@@ -80,6 +81,7 @@ import org.hibernate.resource.jdbc.spi.StatementInspector;
 import org.hibernate.resource.transaction.backend.jta.internal.JtaTransactionCoordinatorImpl;
 import org.hibernate.resource.transaction.spi.TransactionCoordinator;
 import org.hibernate.resource.transaction.spi.TransactionCoordinatorBuilder;
+import org.hibernate.transform.BasicTransformerAdapter;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.sql.SqlTypeDescriptor;
 
@@ -932,12 +934,38 @@ public abstract class AbstractSharedSessionContract implements SharedSessionCont
 	}
 
 	private void handleNativeQueryResult(NativeQueryImplementor query, Class resultClass) {
+		boolean isObjectArray = Object[].class.equals( resultClass );
+
 		if ( Tuple.class.equals( resultClass ) ) {
 			query.setResultTransformer( new NativeQueryTupleTransformer() );
 		}
-		else {
+		else if ( resultClass.isArray() && !isObjectArray ) {
+			Class elementClass = resultClass.getComponentType();
+
+			query.setResultTransformer( new BasicTransformerAdapter() {
+				@Override
+				public Object transformTuple(Object[] tuple, String[] aliases) {
+					Object[] result = (Object[]) Array.newInstance( elementClass, tuple.length );
+					for ( int i = 0; i < tuple.length; i++ ) {
+						result[i] = elementClass.cast( tuple[i] );
+					}
+					return result;
+				}
+			} );
+		}
+		else if ( this.getFactory().getMetamodel().getEntities()
+				.stream()
+				.anyMatch( entityType -> entityType.getJavaType().isAssignableFrom( resultClass ) ) ) {
 			query.addEntity( "alias1", resultClass.getName(), LockMode.READ );
 		}
+		else if ( !isObjectArray ) {
+			query.setResultTransformer( new BasicTransformerAdapter() {
+				@Override
+				public Object transformTuple(Object[] tuple, String[] aliases) {
+					return resultClass.cast( tuple[0] );
+				}
+			} );
+		}
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/jpa/test/query/ScalarResultNativeQueryTest.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.jpa.test.query;
 
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
 import static org.junit.Assert.assertEquals;
 
 import java.util.List;
@@ -20,6 +21,8 @@ import javax.persistence.SqlResultSetMapping;
 import javax.persistence.Table;
 
 import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+
+import org.hibernate.testing.TestForIssue;
 import org.junit.Test;
 
 /**
@@ -58,24 +61,64 @@ public class ScalarResultNativeQueryTest extends BaseEntityManagerFunctionalTest
 
 	@Test
 	public void shouldApplyConfiguredTypeForProjectionOfScalarValue() {
-		EntityManager em = getOrCreateEntityManager();
+		doInJPA( this::entityManagerFactory, entityManager -> {
-		em.getTransaction().begin();
+			entityManager.persist( new Person( 1, 29 ) );
-		em.persist( new Person( 1, 29 ) );
+		} );
-		em.getTransaction().commit();
-		em.close();
 
-		em = getOrCreateEntityManager();
+		doInJPA( this::entityManagerFactory, entityManager -> {
-		em.getTransaction().begin();
+			List<String> results = entityManager.createNamedQuery( "personAge", String.class ).getResultList();
-		List<String> results = em.createNamedQuery( "personAge", String.class ).getResultList();
+			assertEquals( 1, results.size() );
-		assertEquals( 1, results.size() );
+			assertEquals( "29", results.get( 0 ) );
-		assertEquals( "29", results.get( 0 ) );
+		} );
-		em.getTransaction().commit();
+	}
-		em.close();
 
-		em = getOrCreateEntityManager();
+	@Test
-		em.getTransaction().begin();
+	@TestForIssue( jiraKey = "HHH-12670" )
-		em.createQuery( "delete from Person" ).executeUpdate();
+	public void testNativeSQLWithExplicitScalarMapping() {
-		em.getTransaction().commit();
+		doInJPA( this::entityManagerFactory, entityManager -> {
-		em.close();
+			entityManager.persist( new Person( 1, 29 ) );
+		} );
+
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			List<Integer> results = entityManager.createNativeQuery(
+				"select p.age from person p", Integer.class )
+			.getResultList();
+			assertEquals( 1, results.size() );
+			assertEquals( Integer.valueOf( 29 ), results.get( 0 ) );
+		} );
+	}
+
+	@Test
+	@TestForIssue( jiraKey = "HHH-12670" )
+	public void testNativeSQLWithExplicitTypedArrayMapping() {
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			entityManager.persist( new Person( 1, 29 ) );
+		} );
+
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			List<Integer[]> results = entityManager.createNativeQuery(
+					"select p.id, p.age from person p", Integer[].class )
+					.getResultList();
+			assertEquals( 1, results.size() );
+			assertEquals( Integer.valueOf( 1 ), results.get( 0 )[0] );
+			assertEquals( Integer.valueOf( 29 ), results.get( 0 )[1] );
+		} );
+	}
+
+	@Test
+	@TestForIssue( jiraKey = "HHH-12670" )
+	public void testNativeSQLWithObjectArrayMapping() {
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			entityManager.persist( new Person( 1, 29 ) );
+		} );
+
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			List<Object[]> results = entityManager.createNativeQuery(
+					"select p.id, p.age from person p", Object[].class )
+					.getResultList();
+			assertEquals( 1, results.size() );
+			assertEquals( Integer.valueOf( 1 ), results.get( 0 )[0] );
+			assertEquals( Integer.valueOf( 29 ), results.get( 0 )[1] );
+		} );
 	}
 }