HibernateSyncCompassSessionFactory.java

/*
 * Copyright 2004-2009 the original author or authors.
 * 
 * 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.compass.gps.device.hibernate;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.compass.core.Compass;
import org.compass.core.CompassException;
import org.compass.core.CompassSession;
import org.compass.core.CompassSessionFactory;
import org.compass.core.config.CompassSettings;
import org.compass.core.spi.InternalCompassSession;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.engine.SessionImplementor;

/**
 * <p>
 * Integrates with Hibernate transaction managemnet abstraction and Compass
 * transactions. Uses Hibernate support for "context session" including its
 * support for registration of synchronizations with the current transaction.
 * 
 * <p>
 * Will start a Hibernate transaction of none exists, and will join an existing
 * one if one is already in progress. If the Hibernate transcation is started by
 * this transaction factory, it will also be committed by it.
 * 
 * <p>
 * In order to use the transaction factory, it must be configured with Compass,
 * as well as calling {@link #setSessionFactory(org.hibernate.SessionFactory)}
 * before the Compass instance is created.
 * 
 * @author kimchy
 */
public class HibernateSyncCompassSessionFactory implements CompassSessionFactory {

	private static ThreadLocal<SessionFactory> sessionFactoryHolder = new ThreadLocal<SessionFactory>();

	private static String sessionFactoryKey = HibernateSyncCompassSessionFactory.class.getName();

	private SessionFactory sessionFactory;

	private transient Map<Transaction, CompassSession> currentSessionMap = new ConcurrentHashMap<Transaction, CompassSession>();

	public static void setSessionFactory(SessionFactory sessionFactory) {
		sessionFactoryHolder.set(sessionFactory);
	}

	@Override
	public void configure(Compass compass, CompassSettings settings) throws CompassException {
		this.sessionFactory = sessionFactoryHolder.get();
		if (sessionFactory == null) {
			sessionFactory = (SessionFactory) settings.getRegistry(sessionFactoryKey);
		}
		if (sessionFactory != null) {
			settings.setRegistry(sessionFactoryKey, sessionFactory);
		}
		sessionFactoryHolder.set(null);
	}

	protected boolean isWithinExistingTransaction(InternalCompassSession session) throws CompassException {
		return ((SessionImplementor) sessionFactory.getCurrentSession()).isTransactionInProgress();
	}

	public CompassSession getTransactionBoundSession() throws CompassException {
		Session session = sessionFactory.getCurrentSession();
		if (!((SessionImplementor) session).isTransactionInProgress()) {
			return null;
		}
		return currentSessionMap.get(session.getTransaction());
	}

	@Override
	public void setTransactionBoundSession(CompassSession session) {
		if (session == null) {
			currentSessionMap.remove(sessionFactory.getCurrentSession().getTransaction());
		} else {
			currentSessionMap.put(sessionFactory.getCurrentSession().getTransaction(), session);
		}
	}

	public SessionFactory getSessionFactory() {
		return this.sessionFactory;
	}
}