/*
 *  Copyright 2013 Chris Pheby
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.jadira.usertype.spi.jta;

import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceException;

import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.jta.JtaTransactionManager;

/**
 * This class provides an extension of Spring's {@link LocalContainerEntityManagerFactoryBean} which provides a mechanism for associating a PlatformTransactionManager with Hibernate's EntityManager.
 * 
 * To use this class set the Hibernate / JTA property 'hibernate.transaction.jta.platform' to org.jadira.usertype.spi.jta.LocalTransactionManagerPlatform. Then configure the chosen transaction manager
 * via the {@link #setTransactionManager(JtaTransactionManager)} method.
 * 
 * If you are using WebSphere be sure to use the {@link SpringWebSphereUowTransactionManager} as the standard Spring provided implementation will not work with this class.
 */
public class HibernateEntityManagerFactoryBean extends LocalContainerEntityManagerFactoryBean {

    private JtaTransactionManager transactionManager;

    private static final ThreadLocal<JtaTransactionManager> configurationTransactionManagerHolder = new ThreadLocal<JtaTransactionManager>();

    static JtaTransactionManager getConfigurationTransactionManager() {
        return configurationTransactionManagerHolder.get();
    }

    @Override
    protected EntityManagerFactory createNativeEntityManagerFactory() throws PersistenceException {

        if (this.transactionManager != null) {
            configurationTransactionManagerHolder.set(this.transactionManager);
        }

        try {
            return super.createNativeEntityManagerFactory();
        } finally {

            if (this.transactionManager != null) {
                configurationTransactionManagerHolder.set(null);
            }
        }
    }

    /**
     * Associate a transaction manager with this session
     * @param transactionManager The {@link JtaTransactionManager}
     */
    public void setTransactionManager(JtaTransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }
}