/*
 *
 *  * JBoss, Home of Professional Open Source.
 *  * Copyright 2016, Red Hat, Inc., 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.as.jpa.hibernate5;

import java.util.ArrayList;

import javax.enterprise.inject.spi.BeanManager;

import org.hibernate.jpa.event.spi.jpa.ExtendedBeanManager;

/**
 * HibernateExtendedBeanManager helps defer the registering of entity listeners, with the CDI BeanManager until
 * after the persistence unit is available for lookup by CDI bean(s).
 * This solves the WFLY-2387 issue of JPA entity listeners referencing the CDI bean, when the bean cycles back
 * to the persistence unit, or a different persistence unit.
 *
 * @author Scott Marlow
 */
public class HibernateExtendedBeanManager implements ExtendedBeanManager {
    private final ArrayList<LifecycleListener> lifecycleListeners = new ArrayList<>();
    private final BeanManager beanManager;

    public HibernateExtendedBeanManager(BeanManager beanManager) {
        this.beanManager = beanManager;
    }

    /**
     * Hibernate calls registerLifecycleListener to register N callbacks to be notified
     * when the CDI BeanManager can safely be used.  The CDI BeanManager can safely be used
     * when the CDI AfterDeploymentValidation event is reached.
     *
     * @param lifecycleListener
     *
     * Note: Caller (BeanManagerAfterDeploymentValidation) is expected to synchronize calls to
     * registerLifecycleListener() + beanManagerIsAvailableForUse(), which protects
     * HibernateExtendedBeanManager.lifecycleListeners from being read/written from multiple concurrent threads.
     * There are many writer threads (one per deployed persistence unit) and one reader/writer thread expected
     * to be triggered by one AfterDeploymentValidation event per deployment.
     */
    @Override
    public void registerLifecycleListener(LifecycleListener lifecycleListener) {
        lifecycleListeners.add(lifecycleListener);
    }

    public void beanManagerIsAvailableForUse() {
        for (LifecycleListener hibernateCallback : lifecycleListeners) {
            hibernateCallback.beanManagerInitialized(beanManager);
        }
    }

}