HHH-8903 bi-directional fetches in entity graphs

hibernate-core/src/main/java/org/hibernate/graph/spi/GraphNodeImplementor.java

@@ -32,4 +32,5 @@ import javax.persistence.AttributeNode;
 public interface GraphNodeImplementor {
 	List<AttributeNodeImplementor<?>> attributeImplementorNodes();
 	List<AttributeNode<?>> attributeNodes();
+	boolean containsAttribute(String name);
 }

hibernate-core/src/main/java/org/hibernate/loader/plan/build/internal/AbstractEntityGraphVisitationStrategy.java

@@ -45,9 +45,12 @@ import org.hibernate.graph.spi.AttributeNodeImplementor;
 import org.hibernate.graph.spi.GraphNodeImplementor;
 import org.hibernate.internal.CoreLogging;
 import org.hibernate.loader.plan.spi.EntityReturn;
+import org.hibernate.loader.plan.spi.FetchSource;
 import org.hibernate.loader.plan.spi.LoadPlan;
 import org.hibernate.loader.plan.spi.Return;
+import org.hibernate.persister.entity.Joinable;
 import org.hibernate.persister.walking.spi.AssociationAttributeDefinition;
+import org.hibernate.persister.walking.spi.AssociationKey;
 import org.hibernate.persister.walking.spi.AttributeDefinition;
 import org.hibernate.persister.walking.spi.CollectionElementDefinition;
 import org.hibernate.persister.walking.spi.CollectionIndexDefinition;
@@ -330,5 +333,30 @@ public abstract class AbstractEntityGraphVisitationStrategy
 		public List<AttributeNode<?>> attributeNodes() {
 			return Collections.emptyList();
 		}
+		
+		@Override
+		public boolean containsAttribute(String name) {
+			return false;
+		}
 	};
+
+	@Override
+	public void foundCircularAssociation(AssociationAttributeDefinition attributeDefinition) {
+		final FetchStrategy fetchStrategy = determineFetchStrategy( attributeDefinition );
+		if ( fetchStrategy.getStyle() != FetchStyle.JOIN ) {
+			return; // nothing to do
+		}
+
+		// Bi-directional association & the owning side was already visited.  If the current attribute node refers
+		// to it, fetch.
+		// ENTITY nature handled by super.
+		final GraphNodeImplementor graphNode = graphStack.peekLast();
+		if ( attributeDefinition.getAssociationNature() == AssociationAttributeDefinition.AssociationNature.COLLECTION
+				&& ! graphNode.equals( NON_EXIST_SUBGRAPH_NODE)
+				&& graphNode.containsAttribute( attributeDefinition.getName() )) {
+			currentSource().buildCollectionAttributeFetch( attributeDefinition, fetchStrategy );
+		}
+		
+		super.foundCircularAssociation( attributeDefinition );
+	}
 }

hibernate-core/src/main/java/org/hibernate/loader/plan/build/internal/AbstractLoadPlanBuildingAssociationVisitationStrategy.java

@@ -138,7 +138,7 @@ public abstract class AbstractLoadPlanBuildingAssociationVisitationStrategy
 		return last;
 	}
 
-	private ExpandingFetchSource currentSource() {
+	protected ExpandingFetchSource currentSource() {
 		return fetchSourceStack.peekFirst();
 	}
 

hibernate-entitymanager/src/main/java/org/hibernate/jpa/graph/internal/AbstractGraphNode.java

@@ -28,6 +28,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+
 import javax.persistence.AttributeNode;
 import javax.persistence.metamodel.Attribute;
 
@@ -36,7 +37,6 @@ import org.hibernate.graph.spi.GraphNodeImplementor;
 import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.jpa.HibernateEntityManagerFactory;
 import org.hibernate.jpa.spi.HibernateEntityManagerFactoryAware;
-
 import org.jboss.logging.Logger;
 
 /**
@@ -44,7 +44,7 @@ import org.jboss.logging.Logger;
  *
  * @author Steve Ebersole
  */
-public abstract class AbstractGraphNode<T> implements GraphNodeImplementor, HibernateEntityManagerFactoryAware{
+public abstract class AbstractGraphNode<T> implements GraphNodeImplementor, HibernateEntityManagerFactoryAware {
 	private static final Logger log = Logger.getLogger( AbstractGraphNode.class );
 
 	private final HibernateEntityManagerFactory entityManagerFactory;
@@ -200,4 +200,9 @@ public abstract class AbstractGraphNode<T> implements GraphNodeImplementor, Hibe
 	public <X> SubgraphImpl<X> addKeySubgraph(String attributeName, Class<X> type) {
 		return addAttribute( attributeName ).makeKeySubgraph( type );
 	}
+	
+	@Override
+	public boolean containsAttribute(String name) {
+		return attributeNodeMap != null && attributeNodeMap.containsKey( name );
+	}
 }

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/graphs/EntityGraphTest.java

@@ -136,10 +136,14 @@ public class EntityGraphTest extends BaseEntityManagerFunctionalTestCase {
 
    		Bar bar = new Bar();
    		em.persist( bar );
+   		Baz baz = new Baz();
+   		em.persist( baz );
 
    		Foo foo = new Foo();
    		foo.bar = bar;
+   		foo.baz = baz;
         bar.foos.add(foo);
+        baz.foos.add(foo);
    		em.persist( foo );
 
    		em.getTransaction().commit();
@@ -149,7 +153,8 @@ public class EntityGraphTest extends BaseEntityManagerFunctionalTestCase {
 
    		EntityGraph<Foo> fooGraph = em.createEntityGraph( Foo.class );
    		fooGraph.addAttributeNodes("bar");
-        Subgraph barGraph = fooGraph.addSubgraph("bar");
+   		fooGraph.addAttributeNodes("baz");
+        Subgraph<Bar> barGraph = fooGraph.addSubgraph("bar", Bar.class);
         barGraph.addAttributeNodes("foos");
 
    		Map<String, Object> properties = new HashMap<String, Object>();
@@ -160,6 +165,9 @@ public class EntityGraphTest extends BaseEntityManagerFunctionalTestCase {
    		assertTrue( Hibernate.isInitialized( result ) );
    		assertTrue( Hibernate.isInitialized( result.bar ) );
         assertTrue( Hibernate.isInitialized( result.bar.foos) );
+   		assertTrue( Hibernate.isInitialized( result.baz ) );
+   		// sanity check -- ensure the only bi-directional fetch was the one identified by the graph
+        assertFalse( Hibernate.isInitialized( result.baz.foos) );
 
    		em.getTransaction().commit();
    		em.close();
@@ -249,6 +257,9 @@ public class EntityGraphTest extends BaseEntityManagerFunctionalTestCase {
 		@GeneratedValue
         public Integer id;
 
+        @OneToMany(mappedBy = "bar")
+        public Set<Foo> foos = new HashSet<Foo>();
+
 	}
 
 }