EMF.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.jboss.capedwarf.server.api.persistence;

import org.jboss.capedwarf.jpa.EntityManagerProvider;
import org.jboss.capedwarf.jpa.ProxyingFactory;
import org.jboss.capedwarf.jpa.ProxyingWrapper;
import org.jboss.capedwarf.server.api.lifecycle.AfterImpl;
import org.jboss.capedwarf.server.api.lifecycle.BeforeImpl;
import org.jboss.capedwarf.server.api.lifecycle.Notification;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.event.Event;
import javax.enterprise.inject.Produces;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

/**
 * EntityManagerFactory provider.
 *
 * @author <a href="mailto:ales.justin@jboss.org">Ales Justin</a>
 */
@ApplicationScoped
public class EMF {
    private volatile EntityManagerFactory emf;
    private Event<Notification<EntityManagerFactory>> produceEvent;

    @Produces
    @ApplicationScoped
    public EntityManagerFactory produceFactory(EMFInfo info) {
        produceEvent.select(new BeforeImpl()).fire(new EMFNotification(null)); // let app know we're about to create EMF
        EntityManagerFactory entityManagerFactory = getFactory(info);
        produceEvent.select(new AfterImpl()).fire(new EMFNotification(entityManagerFactory)); // let app know we created EMF
        return entityManagerFactory;
    }

    @Produces
    @ApplicationScoped
    public ProxyingFactory produceProxyingFactory(EMFInfo info) {
        return (ProxyingFactory) getFactory(info);
    }

    private EntityManagerFactory getFactory(EMFInfo info) {
        if (emf == null) {
            synchronized (this) {
                if (emf == null) {
                    ProxyingWrapper wrapper = info.getWrapper();
                    EntityManagerFactory delegate = wrapper.lazy(info.getUnitName());
                    EntityManagerProvider provider = new CurrentEntityManagerProvider(delegate, info.getEmInjector());
                    emf = wrapper.wrap(delegate, provider);
                }
            }
        }
        return emf;
    }

    @Inject
    public void setProduceEvent(Event<Notification<EntityManagerFactory>> produceEvent) {
        this.produceEvent = produceEvent;
    }

    private static class CurrentEntityManagerProvider implements EntityManagerProvider {
        private EntityManagerFactory emf;
        private EMInjector emInjector;

        private CurrentEntityManagerProvider(EntityManagerFactory emf, EMInjector emInjector) {
            this.emf = emf;
            this.emInjector = emInjector;
        }

        public EntityManager getEntityManager() {
            EntityManager em = emInjector.getEM();
            return (em != null) ? em : emf.createEntityManager();
        }

        public void close(EntityManager em) {
            EntityManager tmp = emInjector.getEM();
            if (tmp != em)
                em.close();
        }
    }
}