org.apache.fulcrum.cache.impl.JCSCacheService 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.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
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.commons.jcs3.JCS;
import org.apache.commons.jcs3.access.GroupCacheAccess;
import org.apache.commons.jcs3.access.exception.CacheException;
import org.apache.commons.jcs3.engine.ElementAttributes;
import org.apache.commons.jcs3.engine.control.CompositeCacheManager;
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 JCSCacheService
*
* @author Thomas Vandahl
* @version $Id$
*/
public class JCSCacheService 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;
/**
* Instance of the JCS cache
*/
private GroupCacheAccess> cacheManager;
/**
* JCS region to use
*/
private String region;
/**
* Path name of the JCS configuration file
*/
private String configFile;
/**
* Constant value which provides a group name
*/
private static String group = "default_group";
/** 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;
public JCSCacheService()
{
}
// ---------------- Avalon Lifecycle Methods ---------------------
/**
* @see org.apache.avalon.framework.configuration.Configurable#configure(org.apache.avalon.framework.configuration.Configuration)
*/
@Override
public void configure(Configuration config) throws ConfigurationException
{
this.cacheCheckFrequency = config.getChild("cacheCheckFrequency")
.getValueAsLong(DEFAULT_CACHE_CHECK_FREQUENCY);
this.region = config.getChild("region").getValue("fulcrum");
this.configFile = config.getChild("configurationFile").getValue(
"/cache.ccf");
}
/**
* @see org.apache.avalon.framework.activity.Initializable#initialize()
*/
@Override
public void initialize() throws Exception
{
JCS.setConfigFilename(this.configFile);
this.cacheManager = JCS.getGroupCacheInstance(this.region);
// 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("JCSCacheService Refreshing");
this.refreshing.start();
getLogger().debug("JCSCacheService started.");
}
/**
* @see org.apache.avalon.framework.activity.Disposable#dispose()
*/
@Override
public void dispose()
{
this.continueThread = false;
this.refreshing.interrupt();
this.cacheManager.dispose();
this.cacheManager = null;
CompositeCacheManager.getInstance().shutDown();
getLogger().debug("JCSCacheService stopped.");
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getObject(java.lang.String)
*/
@Override
public CachedObject getObject(final String objectId) throws ObjectExpiredException
{
@SuppressWarnings("unchecked")
CachedObject cachedObject = (CachedObject)this.cacheManager.getFromGroup(objectId, group);
if (cachedObject == null)
{
// Not in the cache.
throw new ObjectExpiredException();
}
if (cachedObject.isStale())
{
if (cachedObject instanceof RefreshableCachedObject)
{
RefreshableCachedObject refreshableObject = (RefreshableCachedObject) cachedObject;
if (refreshableObject.isUntouched())
{
// Do not refresh an object that has exceeded TimeToLive
removeObject(objectId);
throw new ObjectExpiredException();
}
// Refresh Object
refreshableObject.refresh();
if (refreshableObject.isStale())
{
// Object is Expired, remove it from cache.
removeObject(objectId);
throw new ObjectExpiredException();
}
}
else
{
// Expired.
removeObject(objectId);
throw new ObjectExpiredException();
}
}
if (cachedObject instanceof RefreshableCachedObject)
{
// notify it that it's being accessed.
RefreshableCachedObject refreshableCachedObject = (RefreshableCachedObject) cachedObject;
refreshableCachedObject.touch();
}
return cachedObject;
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#addObject(java.lang.String,
* org.apache.fulcrum.cache.CachedObject)
*/
@Override
public void addObject(String objectId, CachedObject cachedObject)
{
try
{
if (!(cachedObject.getContents() instanceof Serializable))
{
getLogger()
.warn(
"Object (contents) with id ["
+ objectId
+ "] is not serializable. Expect problems with auxiliary caches: " +
cachedObject.getContents().getClass().getSimpleName());
}
ElementAttributes attrib = (ElementAttributes) this.cacheManager.getDefaultElementAttributes();
if (cachedObject instanceof RefreshableCachedObject)
{
attrib.setIsEternal(true);
}
else
{
attrib.setIsEternal(false);
// expires in millis, maxlife in seconds
double tmp0 = ((double) (cachedObject.getExpires() + 500)) / 1000;
getLogger().debug( "setting maxlife seconds (minimum 1sec) from expiry + 0.5s: " + (int)tmp0 );
attrib.setMaxLife( tmp0 > 0 ? (int) Math.floor( tmp0 ) : 1 );
}
attrib.setLastAccessTimeNow();
attrib.setCreateTime();
this.cacheManager.putInGroup(objectId, group, cachedObject, attrib);
}
catch (CacheException e)
{
getLogger().error("Could not add object " + objectId + " to cache", e);
}
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#removeObject(java.lang.String)
*/
@Override
public void removeObject(String objectId)
{
this.cacheManager.removeFromGroup(objectId, group);
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getKeys()
*/
@Override
public List getKeys()
{
ArrayList keys = new ArrayList<>();
keys.addAll(this.cacheManager.getGroupKeys(group));
return keys;
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getCachedObjects()
*/
@Override
public List> getCachedObjects()
{
ArrayList> values = new ArrayList<>();
for (String key : this.cacheManager.getGroupKeys(group))
{
CachedObject cachedObject = this.cacheManager.getFromGroup(key, group);
if (cachedObject != null)
{
values.add(cachedObject);
}
}
return values;
}
/**
* Circle through the cache and refresh stale objects. Frequency is
* determined by the cacheCheckFrequency property.
*/
@Override
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 (String key : this.cacheManager.getGroupKeys(group))
{
CachedObject cachedObject = this.cacheManager.getFromGroup(key, group);
if (cachedObject == null)
{
removeObject(key);
}
else
{
if (cachedObject instanceof RefreshableCachedObject)
{
RefreshableCachedObject refreshableObject = (RefreshableCachedObject) cachedObject;
if (refreshableObject.isUntouched())
{
this.cacheManager.removeFromGroup(key, group);
}
else if (refreshableObject.isStale())
{
refreshableObject.refresh();
}
}
}
}
}
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getCacheSize()
*/
@Override
public int getCacheSize() throws IOException
{
// This is evil!
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(baos);
Set keys = this.cacheManager.getGroupKeys(group);
for (String key : keys)
{
out.writeObject(this.cacheManager.getFromGroup(key, group));
}
out.flush();
//
// Subtract 4 bytes from the length, because the serialization
// magic number (2 bytes) and version number (2 bytes) are
// both written to the stream before the object
//
return baos.toByteArray().length - 4 * keys.size();
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#getNumberOfObjects()
*/
@Override
public int getNumberOfObjects()
{
int count = 0;
for (String key : this.cacheManager.getGroupKeys(group))
{
if (this.cacheManager.getFromGroup(key, group) != null)
{
count++;
}
}
return count;
}
/**
* @see org.apache.fulcrum.cache.GlobalCacheService#flushCache()
*/
@Override
public void flushCache()
{
this.cacheManager.invalidateGroup(group);
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy