DATAJPA-1280 - Tweaked the type handling for named native queries.

We now only use Tuple as target type to execute a named native query if a projection interface, i.e. an interface that's not part of the entity type's type hierarchy is used as return type. If a type within the entity types hierarchy is returned we use the returned type as type hint. In all other cases (usually DTOs) we rely on the named native query being backed by a custom JPA 2.1 SQL result set mapping.

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

@@ -244,15 +244,12 @@ public abstract class AbstractJpaQuery implements RepositoryQuery {
 	 * @return
 	 * @since 2.0.5
 	 */
-	protected Optional<Class<?>> getTypeToRead() {
+	protected Optional<Class<?>> getTypeToRead(ReturnedType returnedType) {
 
 		if (PersistenceProvider.ECLIPSELINK.equals(provider)) {
 			return Optional.empty();
 		}
 
-		ResultProcessor resultFactory = getQueryMethod().getResultProcessor();
-		ReturnedType returnedType = resultFactory.getReturnedType();
-
 		return returnedType.isProjecting() && !getMetamodel().isJpaManaged(returnedType.getReturnedType())
 				? Optional.of(Tuple.class)
 				: Optional.empty();

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

@@ -23,6 +23,8 @@ import javax.persistence.Query;
 import org.springframework.data.repository.query.EvaluationContextProvider;
 import org.springframework.data.repository.query.ParameterAccessor;
 import org.springframework.data.repository.query.ParametersParameterAccessor;
+import org.springframework.data.repository.query.ResultProcessor;
+import org.springframework.data.repository.query.ReturnedType;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.util.Assert;
 
@@ -78,8 +80,9 @@ abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 
 		ParameterAccessor accessor = new ParametersParameterAccessor(getQueryMethod().getParameters(), values);
 		String sortedQueryString = QueryUtils.applySorting(query.getQueryString(), accessor.getSort(), query.getAlias());
+		ResultProcessor processor = getQueryMethod().getResultProcessor().withDynamicProjection(accessor);
 
-		Query query = createJpaQuery(sortedQueryString);
+		Query query = createJpaQuery(sortedQueryString, processor.getReturnedType());
 
 		// it is ok to reuse the binding contained in the ParameterBinder although we create a new query String because the
 		// parameters in the query do not change.
@@ -132,7 +135,7 @@ abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 	 * Creates an appropriate JPA query from an {@link EntityManager} according to the current {@link AbstractJpaQuery}
 	 * type.
 	 */
-	protected Query createJpaQuery(String queryString) {
+	protected Query createJpaQuery(String queryString, ReturnedType returnedType) {
 
 		EntityManager em = getEntityManager();
 
@@ -140,7 +143,7 @@ abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 			return em.createQuery(queryString);
 		}
 
-		return getTypeToRead() //
+		return getTypeToRead(returnedType) //
 				.<Query> map(it -> em.createQuery(queryString, it)) //
 				.orElseGet(() -> em.createQuery(queryString));
 	}

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

@@ -21,14 +21,18 @@ import java.util.Optional;
 
 import javax.persistence.EntityManager;
 import javax.persistence.Query;
+import javax.persistence.Tuple;
 import javax.persistence.TypedQuery;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.data.jpa.provider.QueryExtractor;
 import org.springframework.data.repository.query.Parameters;
+import org.springframework.data.repository.query.ParametersParameterAccessor;
 import org.springframework.data.repository.query.QueryCreationException;
 import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.data.repository.query.ResultProcessor;
+import org.springframework.data.repository.query.ReturnedType;
 import org.springframework.lang.Nullable;
 
 /**
@@ -155,7 +159,11 @@ final class NamedQuery extends AbstractJpaQuery {
 
 		EntityManager em = getEntityManager();
 
-		Query query = getTypeToRead() //
+		JpaQueryMethod queryMethod = getQueryMethod();
+		ResultProcessor processor = queryMethod.getResultProcessor()
+				.withDynamicProjection(new ParametersParameterAccessor(queryMethod.getParameters(), values));
+
+		Query query = getTypeToRead(processor.getReturnedType()) //
 				.<Query> map(it -> em.createNamedQuery(queryName, it)) //
 				.orElseGet(() -> em.createNamedQuery(queryName));
 
@@ -191,7 +199,29 @@ final class NamedQuery extends AbstractJpaQuery {
 	 * @see org.springframework.data.jpa.repository.query.AbstractJpaQuery#getTypeToRead()
 	 */
 	@Override
-	protected Optional<Class<?>> getTypeToRead() {
-		return declaredQuery.hasConstructorExpression() ? Optional.empty() : super.getTypeToRead();
+	protected Optional<Class<?>> getTypeToRead(ReturnedType returnedType) {
+
+		if (getQueryMethod().isNativeQuery()) {
+
+			Class<?> type = returnedType.getReturnedType();
+			Class<?> domainType = returnedType.getDomainType();
+
+			// Domain or subtype -> use return type
+			if (domainType.isAssignableFrom(type)) {
+				return Optional.of(type);
+			}
+
+			// Domain type supertype -> use domain type
+			if (type.isAssignableFrom(domainType)) {
+				return Optional.of(domainType);
+			}
+
+			// Tuples for projection interfaces or explicit SQL mappings for everything else
+			return type.isInterface() ? Optional.of(Tuple.class) : Optional.empty();
+		}
+
+		return declaredQuery.hasConstructorExpression() //
+				? Optional.empty() //
+				: super.getTypeToRead(returnedType);
 	}
 }

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

@@ -23,7 +23,6 @@ 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;
 
@@ -38,8 +37,6 @@ 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}.
 	 *
@@ -56,11 +53,8 @@ final class NativeJpaQuery extends AbstractStringBasedJpaQuery {
 		Parameters<?, ?> parameters = method.getParameters();
 
 		if (parameters.hasSortParameter() && !queryString.contains("#sort")) {
-			throw new InvalidJpaQueryMethodException(
-					"Cannot use native queries with dynamic sorting in method " + method);
+			throw new InvalidJpaQueryMethodException("Cannot use native queries with dynamic sorting in method " + method);
 		}
-
-		this.resultType = getTypeToQueryFor();
 	}
 
 	/*
@@ -68,19 +62,16 @@ final class NativeJpaQuery extends AbstractStringBasedJpaQuery {
 	 * @see org.springframework.data.jpa.repository.query.AbstractStringBasedJpaQuery#createJpaQuery(java.lang.String)
 	 */
 	@Override
-	protected Query createJpaQuery(String queryString) {
+	protected Query createJpaQuery(String queryString, ReturnedType returnedType) {
 
 		EntityManager em = getEntityManager();
+		Class<?> type = getTypeToQueryFor(returnedType);
 
-		return this.resultType == null ? em.createNativeQuery(queryString)
-				: em.createNativeQuery(queryString, this.resultType);
+		return type == null ? em.createNativeQuery(queryString) : em.createNativeQuery(queryString, type);
 	}
 
 	@Nullable
-	private Class<?> getTypeToQueryFor() {
-
-		ResultProcessor resultFactory = getQueryMethod().getResultProcessor();
-		ReturnedType returnedType = resultFactory.getReturnedType();
+	private Class<?> getTypeToQueryFor(ReturnedType returnedType) {
 
 		Class<?> result = getQueryMethod().isQueryForEntity() ? returnedType.getDomainType() : null;
 

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

@@ -62,7 +62,7 @@ public class AbstractStringBasedJpaQueryIntegrationTests {
 		AbstractStringBasedJpaQuery jpaQuery = new SimpleJpaQuery(method, mock, DefaultEvaluationContextProvider.INSTANCE,
 				new SpelExpressionParser());
 
-		jpaQuery.createJpaQuery(method.getAnnotatedQuery());
+		jpaQuery.createJpaQuery(method.getAnnotatedQuery(), method.getResultProcessor().getReturnedType());
 
 		verify(mock, times(1)).createQuery(anyString());
 		verify(mock, times(0)).createQuery(anyString(), eq(Tuple.class));