//$Id: AbstractReassociateEventListener.java 10949 2006-12-07 21:53:41Z steve.ebersole@jboss.com $
package org.hibernate.event.def;

import java.io.Serializable;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.hibernate.LockMode;
import org.hibernate.engine.EntityEntry;
import org.hibernate.engine.EntityKey;
import org.hibernate.engine.Status;
import org.hibernate.engine.Versioning;
import org.hibernate.event.AbstractEvent;
import org.hibernate.event.EventSource;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.pretty.MessageHelper;
import org.hibernate.type.TypeFactory;

/**
 * A convenience base class for listeners that respond to requests to reassociate an entity
 * to a session ( such as through lock() or update() ).
 *
 * @author Gavin King
 */
public class AbstractReassociateEventListener implements Serializable {

	private static final Log log = LogFactory.getLog( AbstractReassociateEventListener.class );

	/**
	 * Associates a given entity (either transient or associated with another session) to
	 * the given session.
	 *
	 * @param event The event triggering the re-association
	 * @param object The entity to be associated
	 * @param id The id of the entity.
	 * @param persister The entity's persister instance.
	 *
	 * @return An EntityEntry representing the entity within this session.
	 */
	protected final EntityEntry reassociate(AbstractEvent event, Object object, Serializable id, EntityPersister persister) {

		if ( log.isTraceEnabled() ) {
			log.trace(
					"reassociating transient instance: " +
							MessageHelper.infoString( persister, id, event.getSession().getFactory() )
			);
		}

		EventSource source = event.getSession();
		EntityKey key = new EntityKey( id, persister, source.getEntityMode() );

		source.getPersistenceContext().checkUniqueness( key, object );

		//get a snapshot
		Object[] values = persister.getPropertyValues( object, source.getEntityMode() );
		TypeFactory.deepCopy(
				values,
				persister.getPropertyTypes(),
				persister.getPropertyUpdateability(),
				values,
				source
		);
		Object version = Versioning.getVersion( values, persister );

		EntityEntry newEntry = source.getPersistenceContext().addEntity(
				object,
				Status.MANAGED,
				values,
				key,
				version,
				LockMode.NONE,
				true,
				persister,
				false,
				true //will be ignored, using the existing Entry instead
		);

		new OnLockVisitor( source, id, object ).process( object, persister );

		persister.afterReassociate( object, source );

		return newEntry;

	}

}