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Hibernate example source code file (DefaultReplicateEventListener.java)

This example Hibernate source code file (DefaultReplicateEventListener.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Hibernate tags/keywords

defaultreplicateeventlistener, entitypersister, entitypersister, eventsource, eventsource, io, no, object, object, onreplicatevisitor, override, replicationmode, serializable, serializable, type

The Hibernate DefaultReplicateEventListener.java source code

/*
 * 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 org.jboss.logging.Logger;

import org.hibernate.HibernateException;
import org.hibernate.engine.internal.Cascade;
import org.hibernate.engine.spi.CascadingAction;
import org.hibernate.engine.spi.EntityKey;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.engine.spi.Status;
import org.hibernate.event.spi.ReplicateEvent;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.LockMode;
import org.hibernate.ReplicationMode;
import org.hibernate.TransientObjectException;
import org.hibernate.event.spi.EventSource;
import org.hibernate.event.spi.ReplicateEventListener;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.pretty.MessageHelper;
import org.hibernate.type.Type;

/**
 * Defines the default replicate event listener used by Hibernate to replicate
 * entities in response to generated replicate events.
 *
 * @author Steve Ebersole
 */
public class DefaultReplicateEventListener extends AbstractSaveEventListener implements ReplicateEventListener {

    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class,
                                                                       DefaultReplicateEventListener.class.getName());

	/**
	 * Handle the given replicate event.
	 *
	 * @param event The replicate event to be handled.
	 *
	 * @throws TransientObjectException An invalid attempt to replicate a transient entity.
	 */
	public void onReplicate(ReplicateEvent event) {
		final EventSource source = event.getSession();
		if ( source.getPersistenceContext().reassociateIfUninitializedProxy( event.getObject() ) ) {
            LOG.trace("Uninitialized proxy passed to replicate()");
			return;
		}

		Object entity = source.getPersistenceContext().unproxyAndReassociate( event.getObject() );

		if ( source.getPersistenceContext().isEntryFor( entity ) ) {
            LOG.trace("Ignoring persistent instance passed to replicate()");
			//hum ... should we cascade anyway? throw an exception? fine like it is?
			return;
		}

		EntityPersister persister = source.getEntityPersister( event.getEntityName(), entity );

		// get the id from the object
		/*if ( persister.isUnsaved(entity, source) ) {
			throw new TransientObjectException("transient instance passed to replicate()");
		}*/
		Serializable id = persister.getIdentifier( entity, source );
		if ( id == null ) {
			throw new TransientObjectException( "instance with null id passed to replicate()" );
		}

		final ReplicationMode replicationMode = event.getReplicationMode();

		final Object oldVersion;
		if ( replicationMode == ReplicationMode.EXCEPTION ) {
			//always do an INSERT, and let it fail by constraint violation
			oldVersion = null;
		}
		else {
			//what is the version on the database?
			oldVersion = persister.getCurrentVersion( id, source );
		}

		if ( oldVersion != null ) {
            if (LOG.isTraceEnabled()) LOG.trace("Found existing row for "
                                                + MessageHelper.infoString(persister, id, source.getFactory()));

			/// HHH-2378
			final Object realOldVersion = persister.isVersioned() ? oldVersion : null;

			boolean canReplicate = replicationMode.shouldOverwriteCurrentVersion(
					entity,
					realOldVersion,
					persister.getVersion( entity ),
					persister.getVersionType()
			);

            // if can replicate, will result in a SQL UPDATE
            // else do nothing (don't even reassociate object!)
            if (canReplicate) performReplication(entity, id, realOldVersion, persister, replicationMode, source);
            else LOG.trace("No need to replicate");

			//TODO: would it be better to do a refresh from db?
		}
		else {
			// no existing row - do an insert
            if (LOG.isTraceEnabled()) LOG.trace("No existing row, replicating new instance "
                                                + MessageHelper.infoString(persister, id, source.getFactory()));

			final boolean regenerate = persister.isIdentifierAssignedByInsert(); // prefer re-generation of identity!
			final EntityKey key = regenerate ? null : source.generateEntityKey( id, persister );

			performSaveOrReplicate(
					entity,
					key,
					persister,
					regenerate,
					replicationMode,
					source,
					true
			);

		}
	}

	@Override
    protected boolean visitCollectionsBeforeSave(Object entity, Serializable id, Object[] values, Type[] types, EventSource source) {
		//TODO: we use two visitors here, inefficient!
		OnReplicateVisitor visitor = new OnReplicateVisitor( source, id, entity, false );
		visitor.processEntityPropertyValues( values, types );
		return super.visitCollectionsBeforeSave( entity, id, values, types, source );
	}

	@Override
    protected boolean substituteValuesIfNecessary(
			Object entity,
			Serializable id,
			Object[] values,
			EntityPersister persister,
			SessionImplementor source) {
		return false;
	}

	@Override
    protected boolean isVersionIncrementDisabled() {
		return true;
	}

	private void performReplication(
			Object entity,
			Serializable id,
			Object version,
			EntityPersister persister,
			ReplicationMode replicationMode,
			EventSource source) throws HibernateException {

        if (LOG.isTraceEnabled()) LOG.trace("Replicating changes to "
                                            + MessageHelper.infoString(persister, id, source.getFactory()));

		new OnReplicateVisitor( source, id, entity, true ).process( entity, persister );

		source.getPersistenceContext().addEntity(
				entity,
				( persister.isMutable() ? Status.MANAGED : Status.READ_ONLY ),
				null,
				source.generateEntityKey( id, persister ),
				version,
				LockMode.NONE,
				true,
				persister,
				true,
				false
		);

		cascadeAfterReplicate( entity, persister, replicationMode, source );
	}

	private void cascadeAfterReplicate(
			Object entity,
			EntityPersister persister,
			ReplicationMode replicationMode,
			EventSource source) {
		source.getPersistenceContext().incrementCascadeLevel();
		try {
			new Cascade( CascadingAction.REPLICATE, Cascade.AFTER_UPDATE, source )
					.cascade( persister, entity, replicationMode );
		}
		finally {
			source.getPersistenceContext().decrementCascadeLevel();
		}
	}

	@Override
    protected CascadingAction getCascadeAction() {
		return CascadingAction.REPLICATE;
	}
}

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