/*******************************************************************************
 * Copyright (c) 1998, 2012 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the 
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 
 * which accompanies this distribution. 
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *      Oracle - initial impl
 ******************************************************************************/
package example;


import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

/**
 * Uses EclipseLink JPA to read/write an object to a database.
 * @author James Sutherland
 */
public class DatabaseSerializer implements Serializer {
    EntityManagerFactory factory;
    Class lastClass;
    Object lastId;
    
    public DatabaseSerializer() {
        this.factory = Persistence.createEntityManagerFactory("order");
    }
    
    public byte[] serialize(Object object) {
        EntityManager em = this.factory.createEntityManager();
        em.getTransaction().begin();
        em.persist(object);
        this.lastClass = object.getClass();
        this.lastId = this.factory.getPersistenceUnitUtil().getIdentifier(object);
        em.getTransaction().commit();
        return new byte[]{};
    }
    
    public Object deserialize(byte[] bytes) {
        EntityManager em = this.factory.createEntityManager();
        return em.find(this.lastClass, this.lastId);
    }
    
    public String toString() {
        return getClass().getSimpleName();
    }
}