/**
* Copyright 2003-2010 Terracotta, Inc.
*
* 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 net.sf.ehcache.writer.writebehind;
import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheEntry;
import net.sf.ehcache.CacheException;
import net.sf.ehcache.Element;
import net.sf.ehcache.writer.CacheWriter;
import net.sf.ehcache.writer.CacheWriterManager;
/**
* Implements a {@code WriterManager} that writes elements to a queue first and in the background sends the to the {@code CacheWriter}.
*
* @author Geert Bevin
* @version $Id: WriteBehindManager.java 3500 2011-01-23 03:33:55Z gkeim $
*/
public class WriteBehindManager implements CacheWriterManager {
private volatile WriteBehind writeBehind;
/**
* {@inheritDoc}
*/
public void init(Cache cache) throws CacheException {
if (cache.isTerracottaClustered()) {
writeBehind = cache.getCacheManager().createTerracottaWriteBehind(cache);
} else {
writeBehind = new WriteBehindQueueManager(cache.getCacheConfiguration());
}
CacheWriter cacheWriter = cache.getRegisteredCacheWriter();
if (null == cacheWriter) {
throw new CacheException("No cache writer was registered for cache " + cache.getName());
}
if (cache.getCacheConfiguration().getCacheWriterConfiguration().getWriteCoalescing()) {
writeBehind.setOperationsFilter(new CoalesceKeysFilter());
}
writeBehind.start(cacheWriter);
}
/**
* {@inheritDoc}
*/
public void put(Element element) throws CacheException {
writeBehind.write(element);
}
/**
* {@inheritDoc}
*/
public void remove(CacheEntry entry) throws CacheException {
writeBehind.delete(entry);
}
/**
* {@inheritDoc}
*/
public void dispose() {
/* If WriteBehind is configured but no writer is registered, writeBehind will be null */
if (writeBehind != null) {
writeBehind.stop();
}
}
/**
* Gets the best estimate for items in the queue still awaiting processing.
* Not including elements currently processed
* @return the amount of elements still awaiting processing.
*/
public long getQueueSize() {
return writeBehind.getQueueSize();
}
}