/*
* JBoss, Home of Professional Open Source.
* Copyright 2006, 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.resource.connectionmanager;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.concurrent.CopyOnWriteArrayList;
import org.jboss.logging.Logger;
/**
* IdleRemover
*
* @author <a href="mailto:d_jencks@users.sourceforge.net">David Jencks</a>
* @author <a href="mailto:adrian@jboss.com">Adrian Brock</a>
* @author <a href="mailto:weston.price@jboss.com">Weston Price</a>
* @author <a href="mailto:jesper.pedersen@jboss.org">Jesper Pedersen</a>
* @version $Revision: 85731 $
*/
public class IdleRemover
{
private final static Logger log = Logger.getLogger(IdleRemover.class);
private final CopyOnWriteArrayList<IdleConnectionRemovalSupport> pools = new CopyOnWriteArrayList<IdleConnectionRemovalSupport>();
private long interval = Long.MAX_VALUE;
private long next = Long.MAX_VALUE;//important initialization!
private static final IdleRemover remover = new IdleRemover();
private final boolean trace = log.isTraceEnabled();
public static void registerPool(IdleConnectionRemovalSupport mcp, long interval)
{
remover.internalRegisterPool(mcp, interval);
}
public static void unregisterPool(IdleConnectionRemovalSupport mcp)
{
remover.internalUnregisterPool(mcp);
}
/**
* For testing
*/
public static void waitForBackgroundThread()
{
synchronized (remover.pools)
{
return;
}
}
private IdleRemover ()
{
AccessController.doPrivileged(new PrivilegedAction<Object>()
{
public Object run()
{
Runnable runnable = new IdleRemoverRunnable();
Thread removerThread = new Thread(runnable, "IdleRemover");
removerThread.setDaemon(true);
removerThread.start();
return null;
}
});
}
private void internalRegisterPool(IdleConnectionRemovalSupport mcp, long interval)
{
if (trace)
log.trace("internalRegisterPool: registering pool with interval " + interval + " old interval: " + this.interval);
synchronized (pools)
{
pools.addIfAbsent(mcp);
if (interval > 1 && interval/2 < this.interval)
{
this.interval = interval/2;
long maybeNext = System.currentTimeMillis() + this.interval;
if (next > maybeNext && maybeNext > 0)
{
next = maybeNext;
if (trace)
log.trace("internalRegisterPool: about to notify thread: old next: " + next + ", new next: " + maybeNext);
pools.notify();
}
}
}
}
private void internalUnregisterPool(IdleConnectionRemovalSupport mcp)
{
synchronized (pools)
{
pools.remove(mcp);
if (pools.size() == 0)
{
if (trace)
log.trace("internalUnregisterPool: setting interval to Long.MAX_VALUE");
interval = Long.MAX_VALUE;
}
}
}
/**
* Change the context classloader to be where the idle remover was loaded from.<p>
*
* This avoids holding a reference to the caller's classloader which may be undeployed.
*/
private void setupContextClassLoader()
{
// Could be null if loaded from system classloader
final ClassLoader cl = IdleRemover.class.getClassLoader();
if (cl == null)
return;
SecurityManager sm = System.getSecurityManager();
if (sm == null)
Thread.currentThread().setContextClassLoader(cl);
AccessController.doPrivileged(new PrivilegedAction<Object>()
{
public Object run()
{
Thread.currentThread().setContextClassLoader(cl);
return null;
}
});
}
/**
* Idle Remover background thread
*/
private class IdleRemoverRunnable implements Runnable
{
public void run()
{
setupContextClassLoader();
synchronized (pools)
{
while (true)
{
try
{
pools.wait(interval);
if (trace)
log.trace("run: IdleRemover notifying pools, interval: " + interval);
for (IdleConnectionRemovalSupport pool : pools )
pool.removeIdleConnections();
next = System.currentTimeMillis() + interval;
if (next < 0)
next = Long.MAX_VALUE;
}
catch (InterruptedException ie)
{
if (log.isDebugEnabled())
log.debug("run: IdleRemover has been interrupted, ending");
return;
}
catch (RuntimeException e)
{
log.warn("run: IdleRemover ignored unexpected runtime exception", e);
}
catch (Error e)
{
log.warn("run: IdleRemover ignored unexpected error", e);
}
}
}
}
}
}