/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2007, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.cache.jbc.util;

import org.hibernate.cache.jbc.entity.TransactionalAccess;
import org.jboss.cache.config.Option;
import org.jboss.cache.optimistic.DataVersion;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * {@link DataVersion} used in regions where no locking should ever occur. This
 * includes query-caches, update-timestamps caches, collection caches, and
 * entity caches where the entity is not versioned.
 * 
 * @author <a href="brian.stansberry@jboss.com">Brian Stansberry</a>
 * @version $Revision: 1 $
 */
public class NonLockingDataVersion implements DataVersion {

    private static final Logger log = LoggerFactory.getLogger(TransactionalAccess.class);

    private static final long serialVersionUID = 7050722490368630553L;

    public static final DataVersion INSTANCE = new NonLockingDataVersion();

    public static Option getInvocationOption() {
        Option option = new Option();
        option.setDataVersion(INSTANCE);
        return option;
    }

    public boolean newerThan(DataVersion dataVersion) {
//        if (dataVersion instanceof DefaultDataVersion) {
//            log.info("unexpectedly validating against a DefaultDataVersion", new Exception("Just a stack trace"));
//            return true;
//        }
//        else {
            log.trace("non locking lock check...");
            return false;
//        }
    }

}
