/*
* 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 org.jboss.ejb.BeanLock;
import org.jboss.invocation.Invocation;
/**
* The lock interceptors role is to schedule thread wanting to invoke method on a target bean
*
* <p>The policies for implementing scheduling (pessimistic locking etc) is implemented by pluggable
* locks
*
* <p>We also implement serialization of calls in here (this is a spec
* requirement). This is a fine grained notify, notifyAll mechanism. We
* notify on ctx serialization locks and notifyAll on global transactional
* locks.
*
* <p><b>WARNING: critical code</b>, get approval from senior developers
* before changing.
*
* @author <a href="mailto:marc.fleury@jboss.org">Marc Fleury</a>
* @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
* @version $Revision: 81030 $
*
* <p><b>Revisions:</b><br>
* <p><b>2001/07/30: marcf</b>
* <ol>
* <li>Initial revision
* <li>Factorization of the lock out of the context in cache
* <li>The new locking is implement as "scheduling" in the lock which allows for pluggable locks
* </ol>
* <p><b>2001/08/07: billb</b>
* <ol>
* <li>Removed while loop and moved it to SimplePessimisticEJBLock where it belongs.
* </ol>
*/
public class EntityLockInterceptor
extends AbstractInterceptor
{
// Constants -----------------------------------------------------
// Attributes ----------------------------------------------------
// Static --------------------------------------------------------
// Constructors --------------------------------------------------
// Public --------------------------------------------------------
// Interceptor implementation --------------------------------------
public Object invokeHome(Invocation mi)
throws Exception
{
// Invoke through interceptors
return getNext().invokeHome(mi);
}
public Object invoke(Invocation mi)
throws Exception
{
// The key.
Object key = mi.getId();
// The lock.
BeanLock lock ;
boolean threadIsScheduled = false;
boolean trace = log.isTraceEnabled();
if( trace ) log.trace("Begin invoke, key="+key);
lock = container.getLockManager().getLock(key);
try
{
lock.schedule(mi);
try {
return getNext().invoke(mi);
}
finally
{
// we are done with the method, decrease the count, if it reaches 0 it will wake up
// the next thread
lock.sync();
lock.endInvocation(mi);
lock.releaseSync();
}
}
finally
{
// We are done with the lock in general
container.getLockManager().removeLockRef(key);
if( trace ) log.trace("End invoke, key="+key);
}
}
}