001/*
002  GRANITE DATA SERVICES
003  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005  This file is part of Granite Data Services.
006
007  Granite Data Services is free software; you can redistribute it and/or modify
008  it under the terms of the GNU Library General Public License as published by
009  the Free Software Foundation; either version 2 of the License, or (at your
010  option) any later version.
011
012  Granite Data Services is distributed in the hope that it will be useful, but
013  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015  for more details.
016
017  You should have received a copy of the GNU Library General Public License
018  along with this library; if not, see <http://www.gnu.org/licenses/>.
019*/
020
021package org.granite.tide.seam.lazy;
022
023import java.io.Serializable;
024
025import javax.persistence.EntityManager;
026import javax.persistence.Query;
027
028import org.jboss.seam.Component;
029import org.jboss.seam.Entity;
030
031
032/**
033 * Manager responsible for looking up the EntityManager from Seam for the
034 * passed in SessionManagerName
035 * @author CIngram
036 */
037public class SeamEntityManager extends PersistenceContextManager {
038
039        private String emName = null;
040
041        public SeamEntityManager(String emName) {
042            this.emName = emName;
043        }
044        
045        
046        /**
047         * Attach the passed in entity with the EntityManager retrieved
048         * from Seam.
049         * @param entity
050         * @return The attached entity
051         */
052        @Override
053    public Object fetchEntity(Object entity, String[] fetch) {
054        EntityManager em = (EntityManager) Component.getInstance(emName);
055        if (em == null)
056                    throw new RuntimeException("Could not find entity, EntityManager [" + emName + "] not found");
057        
058        Serializable id = (Serializable)Entity.forClass(entity.getClass()).getIdentifier(entity);
059        if (id == null)
060            return null;
061        
062        if (fetch == null || em.getDelegate().getClass().getName().indexOf(".hibernate.") < 0)
063                return em.find(entity.getClass(), id);
064        
065        for (String f : fetch) {
066                Query q = em.createQuery("select e from " + entity.getClass().getName() + " e left join fetch e." + f + " where e = :entity");
067                q.setParameter("entity", entity);
068                entity = q.getSingleResult();
069        }
070        return entity;
071    }
072}