HHH-4772 - Empty conjunction/disjunction in criteria does not follow spec rules

git-svn-id: https://svn.jboss.org/repos/hibernate/core/trunk@18483 1b8cb986-b30d-0410-93ca-fae66ebed9b2

entitymanager/src/main/java/org/hibernate/ejb/criteria/predicate/CompoundPredicate.java

@@ -115,6 +115,11 @@ public class CompoundPredicate
 	}
 
 	public String render(CriteriaQueryCompiler.RenderingContext renderingContext) {
+		if ( getExpressions().size() == 0 ) {
+			return getOperator() == Predicate.BooleanOperator.AND
+					? "true"
+					: "false";
+		}
 		if ( getExpressions().size() == 1 ) {
 			return ( (Renderable) getExpressions().get(0) ).render( renderingContext );
 		}

entitymanager/src/test/java/org/hibernate/ejb/criteria/basic/PredicateTest.java

@@ -0,0 +1,67 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.ejb.criteria.basic;
+
+import javax.persistence.EntityManager;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Root;
+
+import org.hibernate.ejb.metamodel.AbstractMetamodelSpecificTest;
+import org.hibernate.ejb.metamodel.Order;
+
+/**
+ * Test the various predicates.
+ *
+ * @author Steve Ebersole
+ */
+public class PredicateTest extends AbstractMetamodelSpecificTest {
+	public void testEmptyConjunction() {
+		// yes this is a retarded case, but explicitly allowed in the JPA spec
+		CriteriaBuilder builder = factory.getCriteriaBuilder();
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+        CriteriaQuery<Order> orderCriteria = builder.createQuery(Order.class);
+		Root<Order> orderRoot = orderCriteria.from(Order.class);
+		orderCriteria.select(orderRoot);
+		orderCriteria.where( builder.isTrue( builder.conjunction() ) );
+		em.createQuery( orderCriteria ).getResultList();
+		em.getTransaction().commit();
+		em.close();
+	}
+
+	public void testEmptyDisjunction() {
+		// yes this is a retarded case, but explicitly allowed in the JPA spec
+		CriteriaBuilder builder = factory.getCriteriaBuilder();
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+        CriteriaQuery<Order> orderCriteria = builder.createQuery(Order.class);
+		Root<Order> orderRoot = orderCriteria.from(Order.class);
+		orderCriteria.select(orderRoot);
+		orderCriteria.where( builder.isFalse( builder.disjunction() ) );
+		em.createQuery( orderCriteria ).getResultList();
+		em.getTransaction().commit();
+		em.close();
+	}
+}