/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2013, 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.envers.internal.synchronization;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import org.hibernate.ConnectionReleaseMode;
import org.hibernate.FlushMode;
import org.hibernate.Session;
import org.hibernate.action.spi.BeforeTransactionCompletionProcess;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.envers.internal.revisioninfo.RevisionInfoGenerator;
import org.hibernate.envers.internal.synchronization.work.AuditWorkUnit;
import org.hibernate.envers.tools.Pair;
/**
* @author Adam Warski (adam at warski dot org)
*/
public class AuditProcess implements BeforeTransactionCompletionProcess {
private final RevisionInfoGenerator revisionInfoGenerator;
private final SessionImplementor session;
private final LinkedList<AuditWorkUnit> workUnits;
private final Queue<AuditWorkUnit> undoQueue;
private final Map<Pair<String, Object>, AuditWorkUnit> usedIds;
private final EntityChangeNotifier entityChangeNotifier;
private Object revisionData;
public AuditProcess(RevisionInfoGenerator revisionInfoGenerator, SessionImplementor session) {
this.revisionInfoGenerator = revisionInfoGenerator;
this.session = session;
workUnits = new LinkedList<AuditWorkUnit>();
undoQueue = new LinkedList<AuditWorkUnit>();
usedIds = new HashMap<Pair<String, Object>, AuditWorkUnit>();
entityChangeNotifier = new EntityChangeNotifier( revisionInfoGenerator, session );
}
private void removeWorkUnit(AuditWorkUnit vwu) {
workUnits.remove( vwu );
if ( vwu.isPerformed() ) {
// If this work unit has already been performed, it must be deleted (undone) first.
undoQueue.offer( vwu );
}
}
public void addWorkUnit(AuditWorkUnit vwu) {
if ( vwu.containsWork() ) {
final Object entityId = vwu.getEntityId();
if ( entityId == null ) {
// Just adding the work unit - it's not associated with any persistent entity.
workUnits.offer( vwu );
}
else {
final String entityName = vwu.getEntityName();
final Pair<String, Object> usedIdsKey = Pair.make( entityName, entityId );
if ( usedIds.containsKey( usedIdsKey ) ) {
final AuditWorkUnit other = usedIds.get( usedIdsKey );
final AuditWorkUnit result = vwu.dispatch( other );
if ( result != other ) {
removeWorkUnit( other );
if ( result != null ) {
usedIds.put( usedIdsKey, result );
workUnits.offer( result );
}
// else: a null result means that no work unit should be kept
}
// else: the result is the same as the work unit already added. No need to do anything.
}
else {
usedIds.put( usedIdsKey, vwu );
workUnits.offer( vwu );
}
}
}
}
private void executeInSession(Session session) {
// Making sure the revision data is persisted.
final Object currentRevisionData = getCurrentRevisionData( session, true );
AuditWorkUnit vwu;
// First undoing any performed work units
while ( (vwu = undoQueue.poll()) != null ) {
vwu.undo( session );
}
while ( (vwu = workUnits.poll()) != null ) {
vwu.perform( session, revisionData );
entityChangeNotifier.entityChanged( session, currentRevisionData, vwu );
}
}
public Object getCurrentRevisionData(Session session, boolean persist) {
// Generating the revision data if not yet generated
if ( revisionData == null ) {
revisionData = revisionInfoGenerator.generate();
}
// Saving the revision data, if not yet saved and persist is true
if ( !session.contains( revisionData ) && persist ) {
revisionInfoGenerator.saveRevisionData( session, revisionData );
}
return revisionData;
}
@Override
public void doBeforeTransactionCompletion(SessionImplementor session) {
if ( workUnits.size() == 0 && undoQueue.size() == 0 ) {
return;
}
// see: http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4178431
if ( FlushMode.isManualFlushMode( session.getFlushMode() ) ) {
Session temporarySession = null;
try {
temporarySession = ((Session) session).sessionWithOptions().transactionContext().autoClose( false )
.connectionReleaseMode( ConnectionReleaseMode.AFTER_TRANSACTION )
.openSession();
executeInSession( temporarySession );
temporarySession.flush();
}
finally {
if ( temporarySession != null ) {
temporarySession.close();
}
}
}
else {
executeInSession( (Session) session );
// Explicitly flushing the session, as the auto-flush may have already happened.
session.flush();
}
}
}