//$Id: DefaultLockEventListener.java 7019 2005-06-05 05:09:58Z oneovthafew $
package org.hibernate.event.def;
import java.io.Serializable;
import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.TransientObjectException;
import org.hibernate.engine.Cascade;
import org.hibernate.engine.CascadingAction;
import org.hibernate.engine.EntityEntry;
import org.hibernate.engine.ForeignKeys;
import org.hibernate.event.EventSource;
import org.hibernate.event.LockEvent;
import org.hibernate.event.LockEventListener;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.persister.entity.EntityPersister;
/**
* Defines the default lock event listeners used by hibernate to lock entities
* in response to generated lock events.
*
* @author Steve Ebersole
*/
public class DefaultLockEventListener extends AbstractLockUpgradeEventListener implements LockEventListener {
/** Handle the given lock event.
*
* @param event The lock event to be handled.
* @throws HibernateException
*/
public void onLock(LockEvent event) throws HibernateException {
if ( event.getObject() == null ) {
throw new NullPointerException( "attempted to lock null" );
}
if ( event.getLockMode() == LockMode.WRITE ) {
throw new HibernateException( "Invalid lock mode for lock()" );
}
SessionImplementor source = event.getSession();
Object entity = source.getPersistenceContext().unproxyAndReassociate( event.getObject() );
//TODO: if object was an uninitialized proxy, this is inefficient,
// resulting in two SQL selects
EntityEntry entry = source.getPersistenceContext().getEntry(entity);
if (entry==null) {
final EntityPersister persister = source.getEntityPersister( event.getEntityName(), entity );
final Serializable id = persister.getIdentifier( entity, source.getEntityMode() );
if ( !ForeignKeys.isNotTransient( event.getEntityName(), entity, Boolean.FALSE, source ) ) {
throw new TransientObjectException(
"cannot lock an unsaved transient instance: " +
persister.getEntityName()
);
}
entry = reassociate(event, entity, id, persister);
cascadeOnLock(event, persister, entity);
}
upgradeLock( entity, entry, event.getLockMode(), source );
}
private void cascadeOnLock(LockEvent event, EntityPersister persister, Object entity) {
EventSource source = event.getSession();
source.getPersistenceContext().incrementCascadeLevel();
try {
new Cascade(CascadingAction.LOCK, Cascade.AFTER_LOCK, source)
.cascade( persister, entity, event.getLockMode() );
}
finally {
source.getPersistenceContext().decrementCascadeLevel();
}
}
}