org.apache.fulcrum.cache.impl.EHCacheService Maven / Gradle / Ivy
package org.apache.fulcrum.cache.impl;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.
*/
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Element;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.fulcrum.cache.CachedObject;
import org.apache.fulcrum.cache.GlobalCacheService;
import org.apache.fulcrum.cache.ObjectExpiredException;
import org.apache.fulcrum.cache.RefreshableCachedObject;
/**
* Default implementation of EHCacheService
*
* @author Eric Pugh
* @author Thomas Vandahl
*
*/
public class EHCacheService extends AbstractLogEnabled implements
GlobalCacheService, Runnable, Configurable, Disposable, Initializable, ThreadSafe
{
/**
* Cache check frequency in Millis (1000 Millis = 1 second). Value must be >
* 0. Default = 5 seconds
*/
public static final long DEFAULT_CACHE_CHECK_FREQUENCY = 5000; // 5 seconds
/**
* cacheCheckFrequency (default - 5 seconds)
*/
private long cacheCheckFrequency;
/**
* Path name of the JCS configuration file
*/
private String configFile;
/**
* Constant value which provides a cache name
*/
private static final String DEFAULT_CACHE_NAME = "fulcrum";
/**
* A cache name
*/
private String cacheName;
/** thread for refreshing stale items in the cache */
private Thread refreshing;
/** flag to stop the housekeeping thread when the component is disposed. */
private boolean continueThread;
/** The EHCache manager instance */
private CacheManager cacheManager;
/** A cache instance */
private Cache cache;
// ---------------- Avalon Lifecycle Methods ---------------------
/**
* @see org.apache.avalon.framework.configuration.Configurable#configure(org.apache.avalon.framework.configuration.Configuration)
*/
public void configure(Configuration config) throws ConfigurationException
{
this.cacheCheckFrequency = config.getChild("cacheCheckFrequency")
.getValueAsLong(DEFAULT_CACHE_CHECK_FREQUENCY);
this.cacheName = config.getChild("cacheName").getValue(DEFAULT_CACHE_NAME);
this.configFile = config.getChild("configurationFile").getValue(null);
}
/**
* @see org.apache.avalon.framework.activity.Initializable#initialize()
*/
public void initialize() throws Exception
{
if (this.configFile == null)
{
this.cacheManager = new CacheManager();
this.cacheManager.addCache(this.cacheName);
}
else
{
this.cacheManager = new CacheManager(this.configFile);
}
this.cache = this.cacheManager.getCache(this.cacheName);
// Start housekeeping thread.
this.continueThread = true;
this.refreshing = new Thread(this);
// Indicate that this is a system thread. JVM will quit only when
// there are no more active user threads. Settings threads spawned
// internally by Turbine as daemons allows commandline applications
// using Turbine to terminate in an orderly manner.
this.refreshing.setDaemon(true);
this.refreshing.setName("EHCacheService Refreshing");
this.refreshing.start();
getLogger().debug("EHCacheService started!");
}
/**
* @see org.apache.avalon.framework.activity.Disposable#dispose()
*/
public void dispose()
{
this.continueThread = false;
this.refreshing.interrupt();
this.cacheManager.shutdown();
this.cacheManager = null;
this.cache = null;
getLogger().debug("EHCacheService stopped!");
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#addObject(java.lang.String, org.apache.fulcrum.cache.CachedObject)
*/
public void addObject(String id, CachedObject o)
{
Element cacheElement = new Element(id, o);
if (o instanceof RefreshableCachedObject)
{
cacheElement.setEternal(true);
}
else
{
cacheElement.setEternal(false);
cacheElement.setTimeToLive((int)(o.getExpires() + 500) / 1000);
}
cacheElement.setCreateTime();
this.cache.put(cacheElement);
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#flushCache()
*/
public void flushCache()
{
this.cache.removeAll();
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getCachedObjects()
*/
public List getCachedObjects()
{
ArrayList values = new ArrayList();
for (Iterator i = getKeys().iterator(); i.hasNext();)
{
Element cachedElement = this.cache.get(i.next());
if (cachedElement != null)
{
values.add(cachedElement.getObjectValue());
}
}
return values;
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getCacheSize()
*/
public int getCacheSize() throws IOException
{
return (int)this.cache.calculateInMemorySize();
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getKeys()
*/
public List getKeys()
{
return this.cache.getKeysWithExpiryCheck();
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getNumberOfObjects()
*/
public int getNumberOfObjects()
{
return getKeys().size();
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getObject(java.lang.String)
*/
public CachedObject getObject(String id) throws ObjectExpiredException
{
Element cachedElement = this.cache.get(id);
if (cachedElement == null)
{
// Not in the cache.
throw new ObjectExpiredException();
}
CachedObject obj = (CachedObject)cachedElement.getObjectValue();
if (obj.isStale())
{
if (obj instanceof RefreshableCachedObject)
{
RefreshableCachedObject rco = (RefreshableCachedObject) obj;
if (rco.isUntouched())
{
// Do not refresh an object that has exceeded TimeToLive
removeObject(id);
throw new ObjectExpiredException();
}
// Refresh Object
rco.refresh();
if (rco.isStale())
{
// Object is Expired, remove it from cache.
removeObject(id);
throw new ObjectExpiredException();
}
}
else
{
// Expired.
removeObject(id);
throw new ObjectExpiredException();
}
}
if (obj instanceof RefreshableCachedObject)
{
// notify it that it's being accessed.
RefreshableCachedObject rco = (RefreshableCachedObject) obj;
rco.touch();
}
return obj;
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#removeObject(java.lang.String)
*/
public void removeObject(String id)
{
this.cache.remove(id);
}
/**
* Circle through the cache and refresh stale objects. Frequency is
* determined by the cacheCheckFrequency property.
*/
public void run()
{
while (this.continueThread)
{
// Sleep for amount of time set in cacheCheckFrequency -
// default = 5 seconds.
try
{
Thread.sleep(this.cacheCheckFrequency);
}
catch (InterruptedException exc)
{
if (!this.continueThread)
{
return;
}
}
for (Iterator i = getKeys().iterator(); i.hasNext();)
{
String key = (String) i.next();
Element cachedElement = this.cache.get(key);
if (cachedElement == null)
{
this.cache.remove(key);
continue;
}
Object o = cachedElement.getObjectValue();
if (o instanceof RefreshableCachedObject)
{
RefreshableCachedObject rco = (RefreshableCachedObject) o;
if (rco.isUntouched())
{
this.cache.remove(key);
}
else if (rco.isStale())
{
rco.refresh();
}
}
}
}
}
}
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