/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2011, 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.event.internal;
import java.io.Serializable;
import java.util.Map;
import org.hibernate.AssertionFailure;
import org.hibernate.HibernateException;
import org.hibernate.ObjectDeletedException;
import org.hibernate.StaleObjectStateException;
import org.hibernate.WrongClassException;
import org.hibernate.bytecode.instrumentation.spi.FieldInterceptor;
import org.hibernate.engine.internal.Cascade;
import org.hibernate.engine.internal.CascadePoint;
import org.hibernate.engine.spi.CascadingAction;
import org.hibernate.engine.spi.CascadingActions;
import org.hibernate.engine.spi.EntityEntry;
import org.hibernate.engine.spi.EntityKey;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.event.spi.EventSource;
import org.hibernate.event.spi.MergeEvent;
import org.hibernate.event.spi.MergeEventListener;
import org.hibernate.internal.CoreLogging;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.proxy.HibernateProxy;
import org.hibernate.proxy.LazyInitializer;
import org.hibernate.type.ForeignKeyDirection;
import org.hibernate.type.TypeHelper;
/**
* Defines the default copy event listener used by hibernate for copying entities
* in response to generated copy events.
*
* @author Gavin King
*/
public class DefaultMergeEventListener extends AbstractSaveEventListener implements MergeEventListener {
private static final CoreMessageLogger LOG = CoreLogging.messageLogger( DefaultMergeEventListener.class );
@Override
protected Map getMergeMap(Object anything) {
return ( (EventCache) anything ).invertMap();
}
/**
* Handle the given merge event.
*
* @param event The merge event to be handled.
*
* @throws HibernateException
*/
public void onMerge(MergeEvent event) throws HibernateException {
EventCache copyCache = new EventCache( event.getSession() );
onMerge( event, copyCache );
copyCache.clear();
}
/**
* Handle the given merge event.
*
* @param event The merge event to be handled.
*
* @throws HibernateException
*/
public void onMerge(MergeEvent event, Map copiedAlready) throws HibernateException {
final EventCache copyCache = (EventCache) copiedAlready;
final EventSource source = event.getSession();
final Object original = event.getOriginal();
if ( original != null ) {
final Object entity;
if ( original instanceof HibernateProxy ) {
LazyInitializer li = ( (HibernateProxy) original ).getHibernateLazyInitializer();
if ( li.isUninitialized() ) {
LOG.trace( "Ignoring uninitialized proxy" );
event.setResult( source.load( li.getEntityName(), li.getIdentifier() ) );
return; //EARLY EXIT!
}
else {
entity = li.getImplementation();
}
}
else {
entity = original;
}
if ( copyCache.containsKey( entity ) &&
( copyCache.isOperatedOn( entity ) ) ) {
LOG.trace( "Already in merge process" );
event.setResult( entity );
}
else {
if ( copyCache.containsKey( entity ) ) {
LOG.trace( "Already in copyCache; setting in merge process" );
copyCache.setOperatedOn( entity, true );
}
event.setEntity( entity );
EntityState entityState = null;
// Check the persistence context for an entry relating to this
// entity to be merged...
EntityEntry entry = source.getPersistenceContext().getEntry( entity );
if ( entry == null ) {
EntityPersister persister = source.getEntityPersister( event.getEntityName(), entity );
Serializable id = persister.getIdentifier( entity, source );
if ( id != null ) {
final EntityKey key = source.generateEntityKey( id, persister );
final Object managedEntity = source.getPersistenceContext().getEntity( key );
entry = source.getPersistenceContext().getEntry( managedEntity );
if ( entry != null ) {
// we have specialized case of a detached entity from the
// perspective of the merge operation. Specifically, we
// have an incoming entity instance which has a corresponding
// entry in the current persistence context, but registered
// under a different entity instance
entityState = EntityState.DETACHED;
}
}
}
if ( entityState == null ) {
entityState = getEntityState( entity, event.getEntityName(), entry, source );
}
switch ( entityState ) {
case DETACHED:
entityIsDetached( event, copyCache );
break;
case TRANSIENT:
entityIsTransient( event, copyCache );
break;
case PERSISTENT:
entityIsPersistent( event, copyCache );
break;
default: //DELETED
throw new ObjectDeletedException(
"deleted instance passed to merge",
null,
getLoggableName( event.getEntityName(), entity )
);
}
}
}
}
protected void entityIsPersistent(MergeEvent event, Map copyCache) {
LOG.trace( "Ignoring persistent instance" );
//TODO: check that entry.getIdentifier().equals(requestedId)
final Object entity = event.getEntity();
final EventSource source = event.getSession();
final EntityPersister persister = source.getEntityPersister( event.getEntityName(), entity );
( (EventCache) copyCache ).put( entity, entity, true ); //before cascade!
cascadeOnMerge( source, persister, entity, copyCache );
copyValues( persister, entity, entity, source, copyCache );
event.setResult( entity );
}
protected void entityIsTransient(MergeEvent event, Map copyCache) {
LOG.trace( "Merging transient instance" );
final Object entity = event.getEntity();
final EventSource source = event.getSession();
final String entityName = event.getEntityName();
final EntityPersister persister = source.getEntityPersister( entityName, entity );
final Serializable id = persister.hasIdentifierProperty() ?
persister.getIdentifier( entity, source ) :
null;
if ( copyCache.containsKey( entity ) ) {
persister.setIdentifier( copyCache.get( entity ), id, source );
}
else {
( (EventCache) copyCache ).put( entity, source.instantiate( persister, id ), true ); //before cascade!
}
final Object copy = copyCache.get( entity );
// cascade first, so that all unsaved objects get their
// copy created before we actually copy
//cascadeOnMerge(event, persister, entity, copyCache, Cascades.CASCADE_BEFORE_MERGE);
super.cascadeBeforeSave( source, persister, entity, copyCache );
copyValues( persister, entity, copy, source, copyCache, ForeignKeyDirection.FOREIGN_KEY_FROM_PARENT );
saveTransientEntity( copy, entityName, event.getRequestedId(), source, copyCache );
// cascade first, so that all unsaved objects get their
// copy created before we actually copy
super.cascadeAfterSave( source, persister, entity, copyCache );
copyValues( persister, entity, copy, source, copyCache, ForeignKeyDirection.FOREIGN_KEY_TO_PARENT );
event.setResult( copy );
}
private void saveTransientEntity(
Object entity,
String entityName,
Serializable requestedId,
EventSource source,
Map copyCache) {
//this bit is only *really* absolutely necessary for handling
//requestedId, but is also good if we merge multiple object
//graphs, since it helps ensure uniqueness
if ( requestedId == null ) {
saveWithGeneratedId( entity, entityName, copyCache, source, false );
}
else {
saveWithRequestedId( entity, requestedId, entityName, copyCache, source );
}
}
protected void entityIsDetached(MergeEvent event, Map copyCache) {
LOG.trace( "Merging detached instance" );
final Object entity = event.getEntity();
final EventSource source = event.getSession();
final EntityPersister persister = source.getEntityPersister( event.getEntityName(), entity );
final String entityName = persister.getEntityName();
Serializable id = event.getRequestedId();
if ( id == null ) {
id = persister.getIdentifier( entity, source );
}
else {
// check that entity id = requestedId
Serializable entityId = persister.getIdentifier( entity, source );
if ( !persister.getIdentifierType().isEqual( id, entityId, source.getFactory() ) ) {
throw new HibernateException( "merge requested with id not matching id of passed entity" );
}
}
String previousFetchProfile = source.getFetchProfile();
source.setFetchProfile( "merge" );
//we must clone embedded composite identifiers, or
//we will get back the same instance that we pass in
final Serializable clonedIdentifier = (Serializable) persister.getIdentifierType()
.deepCopy( id, source.getFactory() );
final Object result = source.get( entityName, clonedIdentifier );
source.setFetchProfile( previousFetchProfile );
if ( result == null ) {
//TODO: we should throw an exception if we really *know* for sure
// that this is a detached instance, rather than just assuming
//throw new StaleObjectStateException(entityName, id);
// we got here because we assumed that an instance
// with an assigned id was detached, when it was
// really persistent
entityIsTransient( event, copyCache );
}
else {
( (EventCache) copyCache ).put( entity, result, true ); //before cascade!
final Object target = source.getPersistenceContext().unproxy( result );
if ( target == entity ) {
throw new AssertionFailure( "entity was not detached" );
}
else if ( !source.getEntityName( target ).equals( entityName ) ) {
throw new WrongClassException(
"class of the given object did not match class of persistent copy",
event.getRequestedId(),
entityName
);
}
else if ( isVersionChanged( entity, source, persister, target ) ) {
if ( source.getFactory().getStatistics().isStatisticsEnabled() ) {
source.getFactory().getStatisticsImplementor()
.optimisticFailure( entityName );
}
throw new StaleObjectStateException( entityName, id );
}
// cascade first, so that all unsaved objects get their
// copy created before we actually copy
cascadeOnMerge( source, persister, entity, copyCache );
copyValues( persister, entity, target, source, copyCache );
//copyValues works by reflection, so explicitly mark the entity instance dirty
markInterceptorDirty( entity, target, persister );
event.setResult( result );
}
}
private void markInterceptorDirty(final Object entity, final Object target, EntityPersister persister) {
if ( persister.getInstrumentationMetadata().isInstrumented() ) {
FieldInterceptor interceptor = persister.getInstrumentationMetadata().extractInterceptor( target );
if ( interceptor != null ) {
interceptor.dirty();
}
}
}
private boolean isVersionChanged(Object entity, EventSource source, EntityPersister persister, Object target) {
if ( !persister.isVersioned() ) {
return false;
}
// for merging of versioned entities, we consider the version having
// been changed only when:
// 1) the two version values are different;
// *AND*
// 2) The target actually represents database state!
//
// This second condition is a special case which allows
// an entity to be merged during the same transaction
// (though during a seperate operation) in which it was
// originally persisted/saved
boolean changed = !persister.getVersionType().isSame(
persister.getVersion( target ),
persister.getVersion( entity )
);
// TODO : perhaps we should additionally require that the incoming entity
// version be equivalent to the defined unsaved-value?
return changed && existsInDatabase( target, source, persister );
}
private boolean existsInDatabase(Object entity, EventSource source, EntityPersister persister) {
EntityEntry entry = source.getPersistenceContext().getEntry( entity );
if ( entry == null ) {
Serializable id = persister.getIdentifier( entity, source );
if ( id != null ) {
final EntityKey key = source.generateEntityKey( id, persister );
final Object managedEntity = source.getPersistenceContext().getEntity( key );
entry = source.getPersistenceContext().getEntry( managedEntity );
}
}
return entry != null && entry.isExistsInDatabase();
}
protected void copyValues(
final EntityPersister persister,
final Object entity,
final Object target,
final SessionImplementor source,
final Map copyCache) {
final Object[] copiedValues = TypeHelper.replace(
persister.getPropertyValues( entity ),
persister.getPropertyValues( target ),
persister.getPropertyTypes(),
source,
target,
copyCache
);
persister.setPropertyValues( target, copiedValues );
}
protected void copyValues(
final EntityPersister persister,
final Object entity,
final Object target,
final SessionImplementor source,
final Map copyCache,
final ForeignKeyDirection foreignKeyDirection) {
final Object[] copiedValues;
if ( foreignKeyDirection == ForeignKeyDirection.FOREIGN_KEY_TO_PARENT ) {
// this is the second pass through on a merge op, so here we limit the
// replacement to associations types (value types were already replaced
// during the first pass)
copiedValues = TypeHelper.replaceAssociations(
persister.getPropertyValues( entity ),
persister.getPropertyValues( target ),
persister.getPropertyTypes(),
source,
target,
copyCache,
foreignKeyDirection
);
}
else {
copiedValues = TypeHelper.replace(
persister.getPropertyValues( entity ),
persister.getPropertyValues( target ),
persister.getPropertyTypes(),
source,
target,
copyCache,
foreignKeyDirection
);
}
persister.setPropertyValues( target, copiedValues );
}
/**
* Perform any cascades needed as part of this copy event.
*
* @param source The merge event being processed.
* @param persister The persister of the entity being copied.
* @param entity The entity being copied.
* @param copyCache A cache of already copied instance.
*/
protected void cascadeOnMerge(
final EventSource source,
final EntityPersister persister,
final Object entity,
final Map copyCache
) {
source.getPersistenceContext().incrementCascadeLevel();
try {
new Cascade( getCascadeAction(), CascadePoint.BEFORE_MERGE, source ).cascade(
persister,
entity,
copyCache
);
}
finally {
source.getPersistenceContext().decrementCascadeLevel();
}
}
@Override
protected CascadingAction getCascadeAction() {
return CascadingActions.MERGE;
}
@Override
protected Boolean getAssumedUnsaved() {
return Boolean.FALSE;
}
/**
* Cascade behavior is redefined by this subclass, disable superclass behavior
*/
@Override
protected void cascadeAfterSave(EventSource source, EntityPersister persister, Object entity, Object anything)
throws HibernateException {
}
/**
* Cascade behavior is redefined by this subclass, disable superclass behavior
*/
@Override
protected void cascadeBeforeSave(EventSource source, EntityPersister persister, Object entity, Object anything)
throws HibernateException {
}
}