DATAJPA-980 - Native query execution now also uses a Tuple query for projections.

If a projection interface is used as return type for a native query we now trigger a tuple query. Note that this requires Hibernate 5.2.11.

src/main/java/org/springframework/data/jpa/repository/query/AbstractStringBasedJpaQuery.java

@@ -137,9 +137,8 @@ abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 		ResultProcessor resultFactory = getQueryMethod().getResultProcessor();
 		ReturnedType returnedType = resultFactory.getReturnedType();
 
-		getMetamodel().isJpaManaged(returnedType.getReturnedType());
-
-		return returnedType.isProjecting() && !getMetamodel().isJpaManaged(returnedType.getReturnedType())
-				? em.createQuery(queryString, Tuple.class) : em.createQuery(queryString);
+		return returnedType.isProjecting() && !getMetamodel().isJpaManaged(returnedType.getReturnedType()) //
+				? em.createQuery(queryString, Tuple.class) //
+				: em.createQuery(queryString);
 	}
 }

src/main/java/org/springframework/data/jpa/repository/query/NativeJpaQuery.java

@@ -17,10 +17,13 @@ package org.springframework.data.jpa.repository.query;
 
 import javax.persistence.EntityManager;
 import javax.persistence.Query;
+import javax.persistence.Tuple;
 
 import org.springframework.data.repository.query.EvaluationContextProvider;
 import org.springframework.data.repository.query.Parameters;
 import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.data.repository.query.ResultProcessor;
+import org.springframework.data.repository.query.ReturnedType;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 
 /**
@@ -33,6 +36,8 @@ import org.springframework.expression.spel.standard.SpelExpressionParser;
  */
 final class NativeJpaQuery extends AbstractStringBasedJpaQuery {
 
+	private final Class<?> resultType;
+
 	/**
 	 * Creates a new {@link NativeJpaQuery} encapsulating the query annotated on the given {@link JpaQueryMethod}.
 	 * 
@@ -55,6 +60,8 @@ final class NativeJpaQuery extends AbstractStringBasedJpaQuery {
 			throw new InvalidJpaQueryMethodException(
 					"Cannot use native queries with dynamic sorting and/or pagination in method " + method);
 		}
+
+		this.resultType = getTypeToQueryFor();
 	}
 
 	/*
@@ -63,8 +70,25 @@ final class NativeJpaQuery extends AbstractStringBasedJpaQuery {
 	 */
 	@Override
 	protected Query createJpaQuery(String queryString) {
-		return getQueryMethod().isQueryForEntity()
-				? getEntityManager().createNativeQuery(queryString, getQueryMethod().getReturnedObjectType())
-				: getEntityManager().createNativeQuery(queryString);
+
+		EntityManager em = getEntityManager();
+
+		return this.resultType == null ? em.createNativeQuery(queryString)
+				: em.createNativeQuery(queryString, this.resultType);
+	}
+
+	private Class<?> getTypeToQueryFor() {
+
+		ResultProcessor resultFactory = getQueryMethod().getResultProcessor();
+		ReturnedType returnedType = resultFactory.getReturnedType();
+
+		Class<?> result = getQueryMethod().isQueryForEntity() ? returnedType.getDomainType() : null;
+
+		if (this.getQuery().hasConstructorExpression() || this.getQuery().isDefaultProjection()) {
+			return result;
+		}
+
+		return returnedType.isProjecting() && !getMetamodel().isJpaManaged(returnedType.getReturnedType()) ? Tuple.class
+				: result;
 	}
 }

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

@@ -21,8 +21,8 @@ import static org.junit.Assert.*;
 import static org.springframework.data.domain.Example.*;
 import static org.springframework.data.domain.ExampleMatcher.*;
 import static org.springframework.data.domain.Sort.Direction.*;
-import static org.springframework.data.jpa.domain.Specifications.not;
 import static org.springframework.data.jpa.domain.Specifications.*;
+import static org.springframework.data.jpa.domain.Specifications.not;
 import static org.springframework.data.jpa.domain.sample.UserSpecifications.*;
 
 import java.util.ArrayList;
@@ -44,6 +44,7 @@ import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.Root;
 
 import org.hamcrest.Matchers;
+import org.hibernate.Version;
 import org.junit.Assume;
 import org.junit.Before;
 import org.junit.Ignore;
@@ -55,7 +56,8 @@ import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.domain.Example;
 import org.springframework.data.domain.ExampleMatcher;
-import org.springframework.data.domain.ExampleMatcher.*;
+import org.springframework.data.domain.ExampleMatcher.GenericPropertyMatcher;
+import org.springframework.data.domain.ExampleMatcher.StringMatcher;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageImpl;
 import org.springframework.data.domain.PageRequest;
@@ -72,6 +74,7 @@ import org.springframework.data.jpa.domain.sample.User;
 import org.springframework.data.jpa.provider.PersistenceProvider;
 import org.springframework.data.jpa.repository.sample.SampleEvaluationContextExtension.SampleSecurityContextHolder;
 import org.springframework.data.jpa.repository.sample.UserRepository;
+import org.springframework.data.jpa.repository.sample.UserRepository.NameOnly;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
@@ -2155,6 +2158,21 @@ public class UserRepositoryTests {
 		assertThat(users, hasSize(1));
 	}
 
+	@Test // DATAJPA-980
+	public void supportsProjectionsWithNativeQueries() {
+
+		Assume.assumeTrue(Version.getVersionString().startsWith("5.2"));
+
+		flushTestUsers();
+
+		User user = repository.findAll().get(0);
+
+		NameOnly result = repository.findByNativeQuery(user.getId());
+
+		assertThat(result.getFirstname(), is(user.getFirstname()));
+		assertThat(result.getLastname(), is(user.getLastname()));
+	}
+
 	private Page<User> executeSpecWithSort(Sort sort) {
 
 		flushTestUsers();

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

@@ -472,10 +472,20 @@ public interface UserRepository
 
 	List<RolesAndFirstname> findRolesAndFirstnameBy();
 
-	static interface RolesAndFirstname {
+	@Query(value = "SELECT firstname, lastname from SD_User WHERE id = ?1", nativeQuery = true)
+	NameOnly findByNativeQuery(Integer id);
+
+	interface RolesAndFirstname {
 
 		String getFirstname();
 
 		Set<Role> getRoles();
 	}
+
+	interface NameOnly {
+
+		String getFirstname();
+
+		String getLastname();
+	}
 }