HHH-6382: Allow to use @onDelete annotation on unidirectional @onetomany associations

Author: alek-sys

hibernate-core/src/main/java/org/hibernate/cfg/annotations/CollectionBinder.java

@@ -46,6 +46,7 @@
 import org.hibernate.annotations.LazyGroup;
 import org.hibernate.annotations.Loader;
 import org.hibernate.annotations.ManyToAny;
+import org.hibernate.annotations.OnDelete;
 import org.hibernate.annotations.OptimisticLock;
 import org.hibernate.annotations.OrderBy;
 import org.hibernate.annotations.Parameter;
@@ -480,6 +481,15 @@ public void bind() {
 throw new AnnotationException( message );
 }
 
+if (!isMappedBy
+&& oneToMany
+&& property.isAnnotationPresent( OnDelete.class )
+&& !property.isAnnotationPresent( JoinColumn.class )) {
+String message = "Unidirectional one-to-many associations annotated with @OnDelete must define @JoinColumn: ";
+message += StringHelper.qualify( propertyHolder.getPath(), propertyName );
+throw new AnnotationException( message );
+}
+
 collection.setInverse( isMappedBy );
 
 //many to many may need some second pass informations

hibernate-core/src/main/java/org/hibernate/mapping/Collection.java

@@ -293,12 +293,6 @@ public void validate(Mapping mapping) throws MappingException {
 assert getKey() != null : "Collection key not bound : " + getRole();
 assert getElement() != null : "Collection element not bound : " + getRole();
 
-if ( getKey().isCascadeDeleteEnabled() && ( !isInverse() || !isOneToMany() ) ) {
-throw new MappingException(
-"only inverse one-to-many associations may use on-delete=\"cascade\": "
-+ getRole()
-);
-}
 if ( !getKey().isValid( mapping ) ) {
 throw new MappingException(
 "collection foreign key mapping has wrong number of columns: "

hibernate-core/src/test/java/org/hibernate/test/annotations/onetomany/OneToManyTest.java

@@ -6,20 +6,32 @@
  */
 package org.hibernate.test.annotations.onetomany;
 
-import javax.persistence.PersistenceException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.OneToMany;
+import javax.persistence.PersistenceException;
 
+import org.hibernate.AnnotationException;
 import org.hibernate.Hibernate;
-import org.hibernate.HibernateException;
 import org.hibernate.Session;
 import org.hibernate.Transaction;
+import org.hibernate.annotations.OnDelete;
+import org.hibernate.annotations.OnDeleteAction;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistry;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 import org.hibernate.exception.ConstraintViolationException;
 import org.hibernate.mapping.Column;
 import org.hibernate.mapping.PersistentClass;
@@ -36,6 +48,7 @@
 import org.junit.Test;
 
 import static org.hibernate.testing.junit4.ExtraAssertions.assertTyping;
+import static org.hibernate.testing.transaction.TransactionUtil.doInHibernate;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -345,6 +358,46 @@ public void testCascadeDelete() throws Exception {
 s.close();
 }
 
+@Test
+public void testCascadeDeleteWithUnidirectionalAssociation() throws Exception {
+OnDeleteUnidirectionalOneToManyChild child = new OnDeleteUnidirectionalOneToManyChild();
+
+doInHibernate( this::sessionFactory, session -> {
+OnDeleteUnidirectionalOneToManyParent parent = new OnDeleteUnidirectionalOneToManyParent();
+parent.children = Collections.singletonList( child);
+session.persist( parent );
+} );
+
+doInHibernate( this::sessionFactory, session -> {
+session.createQuery("delete from OnDeleteUnidirectionalOneToManyParent").executeUpdate();
+} );
+
+doInHibernate( this::sessionFactory, session -> {
+OnDeleteUnidirectionalOneToManyChild e1 = session.get( OnDeleteUnidirectionalOneToManyChild.class, child.id );
+assertNull( "delete cascade should work", e1 );
+} );
+}
+
+@Test
+public void testOnDeleteWithoutJoinColumn() throws Exception {
+StandardServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
+.build();
+
+try {
+new MetadataSources( serviceRegistry )
+.addAnnotatedClass( OnDeleteUnidirectionalOneToMany.class )
+.addAnnotatedClass( ParentUnawareChild.class )
+.getMetadataBuilder()
+.build();
+}
+catch ( AnnotationException e ) {
+assertTrue(e.getMessage().contains( "Unidirectional one-to-many associations annotated with @OnDelete must define @JoinColumn" ));
+}
+finally {
+StandardServiceRegistryBuilder.destroy( serviceRegistry );
+}
+}
+
 @Test
 public void testSimpleOneToManySet() throws Exception {
 Session s;
@@ -503,12 +556,53 @@ protected Class[] getAnnotatedClasses() {
 Person.class,
 Organisation.class,
 OrganisationUser.class,
-Model.class
+Model.class,
+OnDeleteUnidirectionalOneToManyParent.class,
+OnDeleteUnidirectionalOneToManyChild.class
 };
 }
 
 @Override
 protected String[] getXmlFiles() {
 return new String[] { "org/hibernate/test/annotations/onetomany/orm.xml" };
 }
+
+@Entity(name = "OnDeleteUnidirectionalOneToManyParent")
+public static class OnDeleteUnidirectionalOneToManyParent {
+
+@Id
+@GeneratedValue
+Long id;
+
+@OneToMany(cascade = CascadeType.ALL)
+@JoinColumn(name = "a_id")
+@OnDelete(action = OnDeleteAction.CASCADE)
+List<OnDeleteUnidirectionalOneToManyChild> children;
+}
+
+@Entity(name = "OnDeleteUnidirectionalOneToManyChild")
+public static class OnDeleteUnidirectionalOneToManyChild {
+
+@Id
+@GeneratedValue
+Long id;
+}
+
+@Entity(name = "OnDeleteUnidirectionalOneToMany")
+public static class OnDeleteUnidirectionalOneToMany {
+
+@Id
+Long id;
+
+@OneToMany(cascade = CascadeType.ALL)
+@OnDelete(action = OnDeleteAction.CASCADE)
+List<ParentUnawareChild> children;
+}
+
+@Entity(name = "ParentUnawareChild")
+public static class ParentUnawareChild {
+
+@Id
+Long id;
+}
 }