/*
* 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;
/**
* A ConnectionValidator that performs background validation of managed connections for an
* InternalManagedConnectionPool.
*
* @author <a href="weston.price@jboss.com">Weston Price</a>
* @author <a href="jesper.pedersen@jboss.org">Jesper Pedersen</a>
* @version $Revision: 89154 $
*/
public class ConnectionValidator
{
/** The log */
private static final Logger log = Logger.getLogger(ConnectionValidator.class);
/** The pools */
private final CopyOnWriteArrayList<InternalManagedConnectionPool> pools = new CopyOnWriteArrayList<InternalManagedConnectionPool>();
/** The interval */
private long interval = Long.MAX_VALUE;
/** The next */
private long next = Long.MAX_VALUE;//important initialization!
/** The validator */
private static final ConnectionValidator validator = new ConnectionValidator();
private ConnectionValidator()
{
AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
Runnable runnable = new ConnectionValidatorRunnable();
Thread removerThread = new Thread(runnable, "ConnectionValidator");
removerThread.setDaemon(true);
removerThread.start();
return null;
}
});
}
public static void registerPool(InternalManagedConnectionPool mcp, long interval)
{
validator.internalRegisterPool(mcp, interval);
}
public static void unRegisterPool(InternalManagedConnectionPool mcp)
{
validator.internalUnregisterPool(mcp);
}
private void internalRegisterPool(InternalManagedConnectionPool mcp, long 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 (log.isDebugEnabled())
log.debug("internalRegisterPool: about to notify thread: old next: " + next + ", new next: " + maybeNext);
pools.notify();
}
}
}
}
private void internalUnregisterPool(InternalManagedConnectionPool mcp)
{
synchronized (pools)
{
pools.remove(mcp);
if (pools.size() == 0)
{
if (log.isDebugEnabled())
log.debug("internalUnregisterPool: setting interval to Long.MAX_VALUE");
interval = Long.MAX_VALUE;
}
}
}
private void setupContextClassLoader()
{
// Could be null if loaded from system classloader
final ClassLoader cl = ConnectionValidator.class.getClassLoader();
if (cl == null)
return;
SecurityManager sm = System.getSecurityManager();
if (sm == null)
Thread.currentThread().setContextClassLoader(cl);
AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
Thread.currentThread().setContextClassLoader(cl);
return null;
}
});
}
public static void waitForBackgroundThread()
{
synchronized (validator.pools)
{
return;
}
}
private class ConnectionValidatorRunnable implements Runnable
{
public void run()
{
setupContextClassLoader();
synchronized (pools)
{
while (true)
{
try
{
pools.wait(interval);
if (log.isDebugEnabled())
log.debug("run: ConnectionValidator notifying pools, interval: " + interval);
for (InternalManagedConnectionPool mcp : pools)
{
mcp.validateConnections();
}
next = System.currentTimeMillis() + interval;
if (next < 0)
next = Long.MAX_VALUE;
}
catch (InterruptedException e)
{
Thread.currentThread().interrupt();
log.info("run: ConnectionValidator has been interrupted, returning");
return;
}
catch (RuntimeException e)
{
log.warn("run: ConnectionValidator ignored unexpected runtime exception", e);
}
catch (Exception e)
{
log.warn("run: ConnectionValidator ignored unexpected error", e);
}
}
}
}
}
}