Package org.hibernate.envers.event

Source Code of org.hibernate.envers.event.BaseEnversEventListener

/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 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.envers.event;

import java.io.Serializable;

import org.hibernate.engine.SessionImplementor;
import org.hibernate.envers.configuration.AuditConfiguration;
import org.hibernate.envers.entities.RelationDescription;
import org.hibernate.envers.entities.RelationType;
import org.hibernate.envers.entities.mapper.id.IdMapper;
import org.hibernate.envers.synchronization.AuditProcess;
import org.hibernate.envers.synchronization.work.CollectionChangeWorkUnit;
import org.hibernate.envers.tools.Tools;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.proxy.HibernateProxy;

/**
* Base class for all Envers event listeners
*
* @author Adam Warski (adam at warski dot org)
* @author Hern�n Chanfreau
* @author Steve Ebersole
*/
public abstract class BaseEnversEventListener implements EnversListener {
  private AuditConfiguration enversConfiguration;

  protected BaseEnversEventListener(AuditConfiguration enversConfiguration) {
    this.enversConfiguration = enversConfiguration;
  }

  @Override
  public AuditConfiguration getAuditConfiguration() {
    return enversConfiguration;
  }

  protected final void generateBidirectionalCollectionChangeWorkUnits(
      AuditProcess auditProcess,
      EntityPersister entityPersister,
      String entityName,
      Object[] newState,
      Object[] oldState,
      SessionImplementor session) {
    // Checking if this is enabled in configuration ...
    if ( ! enversConfiguration.getGlobalCfg().isGenerateRevisionsForCollections() ) {
      return;
    }

    // Checks every property of the entity, if it is an "owned" to-one relation to another entity.
    // If the value of that property changed, and the relation is bi-directional, a new revision
    // for the related entity is generated.
    String[] propertyNames = entityPersister.getPropertyNames();

    for ( int i=0; i<propertyNames.length; i++ ) {
      String propertyName = propertyNames[i];
      RelationDescription relDesc = enversConfiguration.getEntCfg().getRelationDescription(entityName, propertyName);
      if (relDesc != null && relDesc.isBidirectional() && relDesc.getRelationType() == RelationType.TO_ONE &&
          relDesc.isInsertable()) {
        // Checking for changes
        Object oldValue = oldState == null ? null : oldState[i];
        Object newValue = newState == null ? null : newState[i];

        if (!Tools.entitiesEqual( session, relDesc.getToEntityName(), oldValue, newValue )) {
          // We have to generate changes both in the old collection (size decreses) and new collection
          // (size increases).
          if (newValue != null) {
            // relDesc.getToEntityName() doesn't always return the entity name of the value - in case
            // of subclasses, this will be root class, no the actual class. So it can't be used here.
            String toEntityName;
            Serializable id;

            if (newValue instanceof HibernateProxy ) {
              HibernateProxy hibernateProxy = (HibernateProxy) newValue;
              toEntityName = session.bestGuessEntityName(newValue);
              id = hibernateProxy.getHibernateLazyInitializer().getIdentifier();
              // We've got to initialize the object from the proxy to later read its state.
              newValue = Tools.getTargetFromProxy(session.getFactory(), hibernateProxy);
            } else {
              toEntityName =  session.guessEntityName(newValue);

              IdMapper idMapper = enversConfiguration.getEntCfg().get(toEntityName).getIdMapper();
               id = (Serializable) idMapper.mapToIdFromEntity(newValue);
            }

            auditProcess.addWorkUnit(new CollectionChangeWorkUnit(session, toEntityName, enversConfiguration, id, newValue));
          }

          if (oldValue != null) {
            String toEntityName;
            Serializable id;

            if(oldValue instanceof HibernateProxy) {
              HibernateProxy hibernateProxy = (HibernateProxy) oldValue;
              toEntityName = session.bestGuessEntityName(oldValue);
              id = hibernateProxy.getHibernateLazyInitializer().getIdentifier();
              // We've got to initialize the object as we'll read it's state anyway.
              oldValue = Tools.getTargetFromProxy(session.getFactory(), hibernateProxy);
            } else {
              toEntityName =  session.guessEntityName(oldValue);

              IdMapper idMapper = enversConfiguration.getEntCfg().get(toEntityName).getIdMapper();
              id = (Serializable) idMapper.mapToIdFromEntity(oldValue);
            }

            auditProcess.addWorkUnit(new CollectionChangeWorkUnit(session, toEntityName, enversConfiguration, id, oldValue));
          }
        }
      }
    }
  }

}
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