/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, 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
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*/
package org.hibernate.tutorial.envers;
import java.util.Date;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import junit.framework.TestCase;
import org.hibernate.envers.AuditReader;
import org.hibernate.envers.AuditReaderFactory;
/**
* Illustrates the set up and use of Envers.
* <p>
* This example is different from the others in that we really need to save multiple revisions to the entity in
* order to get a good look at Envers in action.
*
* @author Steve Ebersole
*/
public class EnversIllustrationTest extends TestCase {
private EntityManagerFactory entityManagerFactory;
@Override
protected void setUp() throws Exception {
// like discussed with regards to SessionFactory, an EntityManagerFactory is set up once for an application
// IMPORTANT: notice how the name here matches the name we gave the persistence-unit in persistence.xml!
entityManagerFactory = Persistence.createEntityManagerFactory( "org.hibernate.tutorial.envers" );
}
@Override
protected void tearDown() throws Exception {
entityManagerFactory.close();
}
public void testBasicUsage() {
// create a couple of events
EntityManager entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
entityManager.persist( new Event( "Our very first event!", new Date() ) );
entityManager.persist( new Event( "A follow up event", new Date() ) );
entityManager.getTransaction().commit();
entityManager.close();
// now lets pull events from the database and list them
entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
List<Event> result = entityManager.createQuery( "from Event", Event.class ).getResultList();
for ( Event event : result ) {
System.out.println( "Event (" + event.getDate() + ") : " + event.getTitle() );
}
entityManager.getTransaction().commit();
entityManager.close();
// so far the code is the same as we have seen in previous tutorials. Now lets leverage Envers...
// first lets create some revisions
entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
Event myEvent = entityManager.find( Event.class, 2L ); // we are using the increment generator, so we know 2 is a valid id
myEvent.setDate( new Date() );
myEvent.setTitle( myEvent.getTitle() + " (rescheduled)" );
entityManager.getTransaction().commit();
entityManager.close();
// and then use an AuditReader to look back through history
entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
myEvent = entityManager.find( Event.class, 2L );
assertEquals( "A follow up event (rescheduled)", myEvent.getTitle() );
AuditReader reader = AuditReaderFactory.get( entityManager );
Event firstRevision = reader.find( Event.class, 2L, 1 );
assertFalse( firstRevision.getTitle().equals( myEvent.getTitle() ) );
assertFalse( firstRevision.getDate().equals( myEvent.getDate() ) );
Event secondRevision = reader.find( Event.class, 2L, 2 );
assertTrue( secondRevision.getTitle().equals( myEvent.getTitle() ) );
assertTrue( secondRevision.getDate().equals( myEvent.getDate() ) );
entityManager.getTransaction().commit();
entityManager.close();
}
}