+/*
+ * 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
+ * Boston, MA 02110-1301 USA
+ */
+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();
+ }
+}