/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
*
* 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.synchronization;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import javax.transaction.Synchronization;
import org.hibernate.envers.revisioninfo.RevisionInfoGenerator;
import org.hibernate.envers.synchronization.work.AuditWorkUnit;
import org.hibernate.envers.tools.Pair;
import org.hibernate.FlushMode;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.event.EventSource;
/**
* @author Adam Warski (adam at warski dot org)
*/
public class AuditSync implements Synchronization {
private final RevisionInfoGenerator revisionInfoGenerator;
private final AuditSyncManager manager;
private final EventSource session;
private final Transaction transaction;
private final LinkedList<AuditWorkUnit> workUnits;
private final Queue<AuditWorkUnit> undoQueue;
private final Map<Pair<String, Object>, AuditWorkUnit> usedIds;
private Object revisionData;
public AuditSync(AuditSyncManager manager, EventSource session, RevisionInfoGenerator revisionInfoGenerator) {
this.manager = manager;
this.session = session;
this.revisionInfoGenerator = revisionInfoGenerator;
transaction = session.getTransaction();
workUnits = new LinkedList<AuditWorkUnit>();
undoQueue = new LinkedList<AuditWorkUnit>();
usedIds = new HashMap<Pair<String, Object>, AuditWorkUnit>();
}
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()) {
Object entityId = vwu.getEntityId();
if (entityId == null) {
// Just adding the work unit - it's not associated with any persistent entity.
workUnits.offer(vwu);
} else {
String entityName = vwu.getEntityName();
Pair<String, Object> usedIdsKey = Pair.make(entityName, entityId);
if (usedIds.containsKey(usedIdsKey)) {
AuditWorkUnit other = usedIds.get(usedIdsKey);
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.
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);
}
}
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;
}
public void beforeCompletion() {
if (workUnits.size() == 0 && undoQueue.size() == 0) {
return;
}
try {
// see: http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4178431
if (FlushMode.isManualFlushMode(session.getFlushMode()) || session.isClosed()) {
Session temporarySession = null;
try {
temporarySession = session.getFactory().openTemporarySession();
executeInSession(temporarySession);
temporarySession.flush();
} finally {
if (temporarySession != null) {
temporarySession.close();
}
}
} else {
executeInSession(session);
// Explicity flushing the session, as the auto-flush may have already happened.
session.flush();
}
} catch (RuntimeException e) {
// Rolling back the transaction in case of any exceptions
//noinspection finally
try {
if (session.getTransaction().isActive()) {
session.getTransaction().rollback();
}
} finally {
//noinspection ThrowFromFinallyBlock
throw e;
}
}
}
public void afterCompletion(int i) {
manager.remove(transaction);
}
}