HHH-13456 refactor ForeignGenerator to allow for the possibility of StatelessSession

hibernate-core/src/main/java/org/hibernate/id/ForeignGenerator.java

@@ -11,6 +11,7 @@
 
 import org.hibernate.MappingException;
 import org.hibernate.Session;
+import org.hibernate.StatelessSession;
 import org.hibernate.TransientObjectException;
 import org.hibernate.engine.internal.ForeignKeys;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
@@ -21,7 +22,6 @@
 import org.hibernate.type.EntityType;
 import org.hibernate.type.Type;
 
-import static org.hibernate.internal.CoreLogging.logger;
 import static org.hibernate.internal.CoreLogging.messageLogger;
 
 /**
@@ -80,9 +80,6 @@ public void configure(Type type, Properties params, ServiceRegistry serviceRegis
 
 	@Override
 	public Serializable generate(SharedSessionContractImplementor sessionImplementor, Object object) {
-		// needs to be a Session for the #save and #contains calls below...
-		final Session session = ( Session ) sessionImplementor;
-
 		final EntityPersister persister = sessionImplementor.getFactory().getMetamodel().entityPersister( entityName );
 		Object associatedObject = persister.getPropertyValue( object, propertyName );
 		if ( associatedObject == null ) {
@@ -117,10 +114,20 @@ public Serializable generate(SharedSessionContractImplementor sessionImplementor
 						foreignValueSourceType.getAssociatedEntityName()
 				);
 			}
-			id = session.save( foreignValueSourceType.getAssociatedEntityName(), associatedObject );
+			if (sessionImplementor instanceof Session) {
+				id = ((Session) sessionImplementor)
+						.save(foreignValueSourceType.getAssociatedEntityName(), associatedObject);
+			}
+			else if (sessionImplementor instanceof StatelessSession) {
+				id = ((StatelessSession) sessionImplementor)
+						.insert(foreignValueSourceType.getAssociatedEntityName(), associatedObject);
+			}
+			else {
+				throw new IdentifierGenerationException("sessionImplementor is neither Session nor StatelessSession");
+			}
 		}
 
-		if ( session.contains( entityName, object ) ) {
+		if ( sessionImplementor instanceof Session && ((Session) sessionImplementor).contains( entityName, object ) ) {
 			//abort the save (the object is already saved by a circular cascade)
 			return IdentifierGeneratorHelper.SHORT_CIRCUIT_INDICATOR;
 			//throw new IdentifierGenerationException("save associated object first, or disable cascade for inverse association");

hibernate-core/src/test/java/org/hibernate/test/id/ForeignGeneratorTest.java

@@ -0,0 +1,70 @@
+package org.hibernate.test.id;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.MapsId;
+import javax.persistence.OneToOne;
+import org.hibernate.Transaction;
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Test;
+
+/**
+ * @author Nathan Xu
+ */
+public class ForeignGeneratorTest extends BaseCoreFunctionalTestCase {
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[] {
+			Product.class,
+			ProductDetails.class
+		};
+	}
+
+	@Test
+	@TestForIssue( jiraKey = "HHH-13456")
+	public void testForeignGeneratorInStatelessSession() {
+
+		inStatelessSession(statelessSession -> {
+
+			Transaction tx = statelessSession.beginTransaction();
+
+			Product product = new Product();
+
+			ProductDetails productDetails = new ProductDetails( product );
+
+			statelessSession.insert( productDetails );
+
+			tx.commit();
+		});
+	}
+
+	@Entity(name = "Product")
+	public static class Product {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+	}
+
+	@Entity(name = "ProductDetails")
+	public static class ProductDetails {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		@OneToOne
+		@MapsId
+		private Product product;
+
+		public ProductDetails() {
+		}
+
+		public ProductDetails( Product product ) {
+			this.product = product;
+		}
+	}
+}

hibernate-testing/src/main/java/org/hibernate/testing/junit4/BaseCoreFunctionalTestCase.java

@@ -20,6 +20,7 @@
 import org.hibernate.HibernateException;
 import org.hibernate.Interceptor;
 import org.hibernate.Session;
+import org.hibernate.StatelessSession;
 import org.hibernate.Transaction;
 import org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl;
 import org.hibernate.boot.registry.BootstrapServiceRegistry;
@@ -387,7 +388,7 @@ protected void cleanupCache() {
 			sessionFactory.getCache().evictAllRegions();
 		}
 	}
-	
+
 	protected boolean isCleanupTestDataRequired() {
 		return false;
 	}
@@ -517,4 +518,8 @@ protected void inTransaction(SessionImplementor session, Consumer<SessionImpleme
 	protected void inSession(Consumer<SessionImplementor> action) {
 		TransactionUtil2.inSession( sessionFactory(), action );
 	}
+
+	protected void inStatelessSession(Consumer<StatelessSession> action) {
+		TransactionUtil2.inStatelessSession( sessionFactory(), action );
+	}
 }