/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.ejb.plugins;
import java.util.TimerTask;
import org.jboss.deployment.DeploymentException;
import org.jboss.metadata.MetaData;
import org.w3c.dom.Element;
/**
* Least Recently Used cache policy for StatefulSessionEnterpriseContexts.
* @author <a href="mailto:simone.bordet@compaq.com">Simone Bordet</a>
* @author Scott.Stark@jboss.org
* @version $Revision: 81030 $
*/
public class LRUStatefulContextCachePolicy extends LRUEnterpriseContextCachePolicy
{
// Constants -----------------------------------------------------
// Attributes ----------------------------------------------------
/* The age after which a bean is automatically removed */
private long m_maxBeanLife;
/* The remover timer task */
private TimerTask m_remover;
/* The period of the remover's runs */
private long m_removerPeriod;
/**
* The typed stateful cache
*/
private StatefulSessionInstanceCache ssiCache;
// Static --------------------------------------------------------
// Constructors --------------------------------------------------
/**
* Creates a LRU cache policy object given the instance cache that use this
* policy object.
*/
public LRUStatefulContextCachePolicy(AbstractInstanceCache eic)
{
super(eic);
ssiCache = (StatefulSessionInstanceCache) eic;
}
// Public --------------------------------------------------------
// Monitorable implementation ------------------------------------
// Z implementation ----------------------------------------------
public void start()
{
super.start();
if (m_maxBeanLife > 0)
{
m_remover = new RemoverTask(m_removerPeriod);
long delay = (long) (Math.random() * m_removerPeriod);
tasksTimer.schedule(m_remover, delay, m_removerPeriod);
}
}
public void stop()
{
if (m_remover != null)
{
m_remover.cancel();
}
super.stop();
}
/**
* Reads from the configuration the parameters for this cache policy, that
* are all optionals.
*/
public void importXml(Element element) throws DeploymentException
{
super.importXml(element);
String rp = MetaData.getElementContent(MetaData.getOptionalChild(element, "remover-period"));
String ml = MetaData.getElementContent(MetaData.getOptionalChild(element, "max-bean-life"));
try
{
if (rp != null)
{
int p = Integer.parseInt(rp);
if (p <= 0)
{
throw new DeploymentException("Remover period can't be <= 0");
}
m_removerPeriod = p * 1000;
}
if (ml != null)
{
int a = Integer.parseInt(ml);
if (a <= 0)
{
throw new DeploymentException("Max bean life can't be <= 0");
}
m_maxBeanLife = a * 1000;
}
}
catch (NumberFormatException x)
{
throw new DeploymentException("Can't parse policy configuration", x);
}
}
// Y overrides ---------------------------------------------------
// Package protected ---------------------------------------------
// Protected -----------------------------------------------------
// Private -------------------------------------------------------
// Inner classes -------------------------------------------------
/**
* This TimerTask removes beans that have not been called for a while.
*/
protected class RemoverTask extends OveragerTask
{
protected RemoverTask(long period)
{
super(period);
}
protected String getTaskLogMessage()
{
return "Removing from cache bean";
}
protected void kickOut(LRUCacheEntry entry)
{
remove(entry.m_key);
}
protected long getMaxAge()
{
return m_maxBeanLife;
}
public void run()
{
if (ssiCache == null)
{
cancel();
return;
}
synchronized (ssiCache.getCacheLock())
{
log.debug("Running RemoverTask");
// Remove beans from cache and passivate them
super.run();
log.debug("RemoverTask, PassivatedCount=" + ssiCache.getPassivatedCount());
}
try
{
// Throw away any passivated beans that have expired
ssiCache.removePassivated(getMaxAge() - super.getMaxAge());
log.debug("RemoverTask, done");
}
catch (Throwable t)
{
log.debug("Ignored error trying to remove passivated beans from cache", t);
}
}
}
}