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    
021    package org.granite.tide.seam.lazy;
022    
023    import java.io.Serializable;
024    
025    import javax.persistence.EntityManager;
026    import javax.persistence.Query;
027    
028    import org.jboss.seam.Component;
029    import 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     */
037    public 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    }