DATAJPA-1822 - workaround for EclipseLink

Author: pblanchardie

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

@@ -50,6 +50,7 @@
 import javax.persistence.metamodel.Bindable;
 import javax.persistence.metamodel.ManagedType;
 import javax.persistence.metamodel.PluralAttribute;
+import javax.persistence.metamodel.SingularAttribute;
 
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
@@ -688,13 +689,19 @@ private static boolean requiresOuterJoin(From<?, ?> from, PropertyPath property,
 		Bindable<?> propertyPathModel;
 		Bindable<?> model = from.getModel();
 
+		// required for EclipseLink: we try to avoid using from.get as EclipseLink produces an inner join
+		// regardless of which join operation is specified next
+		// see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=413892
+		// still occurs as of 2.7
+		ManagedType<?> managedType = null;
 		if (model instanceof ManagedType) {
-
-			/*
-			 *  Required to keep support for EclipseLink 2.4.x. TODO: Remove once we drop that (probably Dijkstra M1)
-			 *  See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=413892
-			 */
-			propertyPathModel = (Bindable<?>) ((ManagedType<?>) model).getAttribute(segment);
+			managedType = (ManagedType<?>) model;
+		} else if (model instanceof SingularAttribute
+				       && ((SingularAttribute<?, ?>) model).getType() instanceof ManagedType) {
+			managedType = (ManagedType<?>) ((SingularAttribute<?, ?>) model).getType();
+		}
+		if (managedType != null) {
+			propertyPathModel = (Bindable<?>) managedType.getAttribute(segment);
 		} else {
 			propertyPathModel = from.get(segment).getModel();
 		}

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

@@ -27,8 +27,4 @@ int getNumberOfJoinsAfterCreatingAPath() {
 		return 1;
 	}
 
-	boolean isSkipOptionalDetection() {
-		return true;
-	}
-
 }

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

@@ -118,9 +118,6 @@ void createsJoinForOptionalOneToOneInReverseDirection() {
 	@Test // DATAJPA-1822
 	void createsLeftJoinForOptionalToOneWithNestedNonOptional() {
 
-		if(isSkipOptionalDetection())
-			return;
-
 		CriteriaBuilder builder = em.getCriteriaBuilder();
 		CriteriaQuery<Invoice> query = builder.createQuery(Invoice.class);
 		Root<Invoice> root = query.from(Invoice.class);
@@ -137,9 +134,6 @@ void createsLeftJoinForOptionalToOneWithNestedNonOptional() {
 	@Test // DATAJPA-1822
 	void createsLeftJoinForNonOptionalToOneWithNestedOptional() {
 
-		if(isSkipOptionalDetection())
-			return;
-
 		CriteriaBuilder builder = em.getCriteriaBuilder();
 		CriteriaQuery<InvoiceItem> query = builder.createQuery(InvoiceItem.class);
 		Root<InvoiceItem> root = query.from(InvoiceItem.class);
@@ -159,9 +153,6 @@ void createsLeftJoinForNonOptionalToOneWithNestedOptional() {
 	@Test // DATAJPA-1822
 	void reusesLeftJoinForNonOptionalToOneWithNestedOptional() {
 
-		if(isSkipOptionalDetection())
-			return;
-
 		CriteriaBuilder builder = em.getCriteriaBuilder();
 		CriteriaQuery<InvoiceItem> query = builder.createQuery(InvoiceItem.class);
 		Root<InvoiceItem> root = query.from(InvoiceItem.class);
@@ -186,9 +177,6 @@ void reusesLeftJoinForNonOptionalToOneWithNestedOptional() {
 	@Test // DATAJPA-1822
 	void reusesInnerJoinForNonOptionalToOneWithNestedOptional() {
 
-		if(isSkipOptionalDetection())
-			return;
-
 		CriteriaBuilder builder = em.getCriteriaBuilder();
 		CriteriaQuery<InvoiceItem> query = builder.createQuery(InvoiceItem.class);
 		Root<InvoiceItem> root = query.from(InvoiceItem.class);
@@ -344,10 +332,6 @@ int getNumberOfJoinsAfterCreatingAPath() {
 		return 0;
 	}
 
-	boolean isSkipOptionalDetection() {
-		return false;
-	}
-
 	private Set<Join<?, ?>> getNonInnerJoins(Root<?> root) {
 
 		return getNonInnerJoins((From<?, ?>) root);