/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2005 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * 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.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.util.objectwrapper.impl;
  
  import java.io.Serializable;
  
  import org.hibernate.EntityMode;
  import org.hibernate.SessionFactory;
  import org.hibernate.metadata.ClassMetadata;
  
  import ch.elca.el4j.util.objectwrapper.ObjectWrapperRTException;
  import ch.elca.el4j.util.objectwrapper.interfaces.KeyedVersioned;
  
  
  /**
   * Implementation of keyed/versioned.
   *
   * @svnLink $Revision: 3879 $;$Date: 2009-08-04 15:13:46 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/hibernate/src/main/java/ch/elca/el4j/util/objectwrapper/impl/KeyedVersionedHibernateImpl.java $
   *
   * @author David Bernhard (DBD)
   */
  public class KeyedVersionedHibernateImpl extends AbstractWrapper implements KeyedVersioned {
  
  	/** The session factory - source of hibernate metadata. */
  	private final SessionFactory m_sessionFactory;
  
  	/** The class metadata, retrieved once from the session factory on create(). */
  	private ClassMetadata m_meta;
  	
  	/**
  	 * Create a prototype instance.
  	 * @param sessionFactory The session factory.
  	 */
  	public KeyedVersionedHibernateImpl(SessionFactory sessionFactory) {
  		m_sessionFactory = sessionFactory;
  	}
  
  	/** {@inheritDoc} */
  	public Serializable getKey() {
  		return m_meta.getIdentifier(m_target, EntityMode.POJO);
  	}
  
  	/** {@inheritDoc} */
  	public Serializable getVersion() {
  		return (Serializable) m_meta.getVersion(m_target, EntityMode.POJO);
  	}
  
  	/** {@inheritDoc} */
  	public void setKey(Serializable key) {
  		m_meta.setIdentifier(m_target, key, EntityMode.POJO);
  	}
  
  	/** {@inheritDoc} */
  	public void setVersion(Serializable version) {
  		// This is a workaround.
  		// We do not have a setVersion method on hibernate's metadata,
  		// so we need to get the version property's index, look up its name
  		// with the index in the list of names and set it by name as a property.
  		String versionName = m_meta.getPropertyNames()[m_meta.getVersionProperty()];
  		m_meta.setPropertyValue(m_target, versionName, version, EntityMode.POJO);
  	}
  	
  	/** {@inheritDoc} */
  	public Class<?> getKeyClass() {
  		return m_meta.getIdentifierType().getReturnedClass();
  	}
  	
  	/** {@inheritDoc} */
  	public Class<?> getVersionClass() {
  		String versionName = m_meta.getPropertyNames()[m_meta.getVersionProperty()];
  		return m_meta.getPropertyType(versionName).getReturnedClass();
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	public void create() {
  		m_meta = m_sessionFactory.getClassMetadata(m_target.getClass());
  		if (m_meta == null || m_meta.getIdentifierPropertyName() == null) {
  			throw new ObjectWrapperRTException("Failed to create hibernate metadata.");
  		}
  	}
  
  }