Hibernate example source code file (ReadWriteEhcacheEntityRegionAccessStrategy.java)

This example Hibernate source code file (ReadWriteEhcacheEntityRegionAccessStrategy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

abstractreadwriteehcacheaccessstrategy, cacheexception, cacheexception, entityregionaccessstrategy, item, lock, lock, lockable, lockable, object, object, readwriteehcacheentityregionaccessstrategy, settings, softlock

The Hibernate ReadWriteEhcacheEntityRegionAccessStrategy.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2011, Red Hat Inc. 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 Inc.
 *
 * 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.ehcache.internal.strategy;

import org.hibernate.cache.CacheException;
import org.hibernate.cache.ehcache.internal.regions.EhcacheEntityRegion;
import org.hibernate.cache.spi.EntityRegion;
import org.hibernate.cache.spi.access.EntityRegionAccessStrategy;
import org.hibernate.cache.spi.access.SoftLock;
import org.hibernate.cfg.Settings;

/**
 * Ehcache specific read/write entity region access strategy
 *
 * @author Chris Dennis
 * @author Alex Snaps
 */
public class ReadWriteEhcacheEntityRegionAccessStrategy
		extends AbstractReadWriteEhcacheAccessStrategy<EhcacheEntityRegion>
		implements EntityRegionAccessStrategy {

	/**
	 * Create a read/write access strategy accessing the given entity region.
	 */
	public ReadWriteEhcacheEntityRegionAccessStrategy(EhcacheEntityRegion region, Settings settings) {
		super( region, settings );
	}

	/**
	 * {@inheritDoc}
	 */
	public EntityRegion getRegion() {
		return region;
	}

	/**
	 * A no-op since this is an asynchronous cache access strategy.
	 */
	public boolean insert(Object key, Object value, Object version) throws CacheException {
		return false;
	}

	/**
	 * {@inheritDoc}
	 * <p/>
	 * Inserts will only succeed if there is no existing value mapped to this key.
	 */
	public boolean afterInsert(Object key, Object value, Object version) throws CacheException {
		region.writeLock( key );
		try {
			Lockable item = (Lockable) region.get( key );
			if ( item == null ) {
				region.put( key, new Item( value, version, region.nextTimestamp() ) );
				return true;
			}
			else {
				return false;
			}
		}
		finally {
			region.writeUnlock( key );
		}
	}

	/**
	 * A no-op since this is an asynchronous cache access strategy.
	 */
	public boolean update(Object key, Object value, Object currentVersion, Object previousVersion)
			throws CacheException {
		return false;
	}

	/**
	 * {@inheritDoc}
	 * <p/>
	 * Updates will only succeed if this entry was locked by this transaction and exclusively this transaction for the
	 * duration of this transaction.  It is important to also note that updates will fail if the soft-lock expired during
	 * the course of this transaction.
	 */
	public boolean afterUpdate(Object key, Object value, Object currentVersion, Object previousVersion, SoftLock lock)
			throws CacheException {
		//what should we do with previousVersion here?
		region.writeLock( key );
		try {
			Lockable item = (Lockable) region.get( key );

			if ( item != null && item.isUnlockable( lock ) ) {
				Lock lockItem = (Lock) item;
				if ( lockItem.wasLockedConcurrently() ) {
					decrementLock( key, lockItem );
					return false;
				}
				else {
					region.put( key, new Item( value, currentVersion, region.nextTimestamp() ) );
					return true;
				}
			}
			else {
				handleLockExpiry( key, item );
				return false;
			}
		}
		finally {
			region.writeUnlock( key );
		}
	}
}