defaultupdateeventlistener.java

介绍了hibernate的入门有一些基本常用的事例

//$Id: DefaultUpdateEventListener.java,v 1.2 2005/02/22 03:09:35 oneovthafew Exp $
package org.hibernate.event.def;

import java.io.Serializable;

import org.hibernate.HibernateException;
import org.hibernate.ObjectDeletedException;
import org.hibernate.EntityMode;
import org.hibernate.engine.EntityEntry;
import org.hibernate.engine.Status;
import org.hibernate.event.SaveOrUpdateEvent;
import org.hibernate.persister.entity.EntityPersister;

/**
 * An event handler for update() events
 * @author Gavin King
 */
public class DefaultUpdateEventListener extends DefaultSaveOrUpdateEventListener {

	protected Serializable performSaveOrUpdate(SaveOrUpdateEvent event) {
		// this implementation is supposed to tolerate incorrect unsaved-value
		// mappings, for the purpose of backward-compatibility
		EntityEntry entry = event.getSession().getPersistenceContext().getEntry( event.getEntity() );
		if ( entry!=null ) {
			if ( entry.getStatus()==Status.DELETED ) {
				throw new ObjectDeletedException( "deleted instance passed to update()", null, event.getEntityName() );
			}
			else {
				return entityIsPersistent(event);
			}
		}
		else {
			entityIsDetached(event);
			return null;
		}
	}
	
	/**
	 * If the user specified an id, assign it to the instance and use that, 
	 * otherwise use the id already assigned to the instance
	 */
	protected Serializable getUpdateId(Object entity, EntityPersister persister, Serializable requestedId, EntityMode entityMode)
	throws HibernateException {

		if ( requestedId==null ) {
			return super.getUpdateId(entity, persister, requestedId, entityMode);
		}
		else {
			persister.setIdentifier(entity, requestedId, entityMode);
			return requestedId;
		}
	}

}