Fall back to collection if stream query has custom result set extractor

Specifying a custom result set extractor doesn't make sense when using
streams because the result set extractor always considers the entire
result. This loads the entire stream into memory anyways.

Author: denniseffing

Diff for: spring-data-jdbc/src/main/java/org/springframework/data/jdbc/repository/query/AbstractJdbcQuery.java

@@ -95,7 +95,7 @@ protected JdbcQueryExecution<?> getQueryExecution(JdbcQueryMethod queryMethod,
 		}
 
 		if (queryMethod.isStreamQuery()) {
-			return streamQuery(rowMapper);
+			return extractor != null ? getQueryExecution(extractor) : streamQuery(rowMapper);
 		}
 
 		return extractor != null ? getQueryExecution(extractor) : singleObjectQuery(rowMapper);

Diff for: spring-data-jdbc/src/test/java/org/springframework/data/jdbc/repository/query/StringBasedJdbcQueryUnitTests.java

@@ -27,6 +27,7 @@
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
 import org.springframework.dao.DataAccessException;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
@@ -140,6 +141,18 @@ public void streamQueryCallsQueryForStreamOnOperations() {
 		verify(operations).queryForStream(eq("some sql statement"), any(SqlParameterSource.class), any(RowMapper.class));
 	}
 
+	@Test // DATAJDBC-356
+	void streamQueryFallsBackToCollectionQueryWhenCustomResultSetExtractorIsSpecified() {
+		JdbcQueryMethod queryMethod = createMethod("findAllWithStreamReturnTypeAndResultSetExtractor");
+		StringBasedJdbcQuery query = createQuery(queryMethod);
+
+		query.execute(new Object[] {});
+
+		ArgumentCaptor<ResultSetExtractor> captor = ArgumentCaptor.forClass(ResultSetExtractor.class);
+		verify(operations).query(eq("some sql statement"), any(SqlParameterSource.class), captor.capture());
+		assertThat(captor.getValue()).isInstanceOf(CustomResultSetExtractor.class);
+	}
+
 	@Test // GH-774
 	public void sliceQueryNotSupported() {
 
@@ -189,6 +202,9 @@ interface MyRepository extends Repository<Object, Long> {
 		@Query(value = "some sql statement")
 		Stream<Object> findAllWithStreamReturnType();
 
+		@Query(value = "some sql statement", resultSetExtractorClass = CustomResultSetExtractor.class)
+		Stream<Object> findAllWithStreamReturnTypeAndResultSetExtractor();
+
 		List<Object> noAnnotation();
 
 		@Query(value = "some sql statement")