/**
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig licenses this file to you 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.jasig.portal.utils.cache;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Ehcache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Evicts expired elements from a {@link CacheManager}
*
* @author Eric Dalquist
*/
public class ExpiredElementEvictor {
private final ReentrantLock evictLock = new ReentrantLock();
protected final Logger logger = LoggerFactory.getLogger(getClass());
private CacheManager cacheManager;
public void setCacheManager(CacheManager cacheManager) {
this.cacheManager = cacheManager;
}
/**
* Evicts expired elements from the {@link CacheManager}
*/
public void evictExpiredElements() {
long evictedTotal = 0;
final long startTime;
final String[] cacheNames;
if (!evictLock.tryLock()) {
//Lock is already held, skip eviction
return;
}
try {
startTime = System.nanoTime();
cacheNames = this.cacheManager.getCacheNames();
for (String cacheName : cacheNames) {
final Ehcache cache = this.cacheManager.getEhcache(cacheName);
if (null != cache) {
final long preEvictSize = cache.getMemoryStoreSize();
final long evictStart = System.nanoTime();
cache.evictExpiredElements();
if (logger.isDebugEnabled()) {
final long evicted = preEvictSize - cache.getMemoryStoreSize();
evictedTotal += evicted;
logger.debug("Evicted " + evicted + " elements from cache '" + cacheName + "' in "
+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - evictStart) + " ms");
}
}
else if (logger.isDebugEnabled()) {
logger.debug("No cache found with name " + cacheName);
}
}
}
finally {
this.evictLock.unlock();
}
if (logger.isDebugEnabled()) {
logger.debug("Evicted " + evictedTotal + " elements from " + cacheNames.length + " caches in "
+ this.cacheManager.getName() + " in "
+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime) + " ms");
}
}
}