/*
* 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.rmi.NoSuchObjectException;
import java.rmi.RemoteException;
import org.jboss.ejb.EnterpriseContext;
/**
* SFSB cache for clustered environment. Mainly avoid "excessive" locking
* that can generate cluster-distributed deadlocks.
*
* @see org.jboss.ejb.plugins.StatefulSessionInstanceCache
*
* @author <a href="mailto:sacha.labourey@cogito-info.ch">Sacha Labourey</a>.
* @version $Revision: 81001 $
*
* <p><b>Revisions:</b>
*
* <p><b>19 decembre 2002 Sacha Labourey:</b>
* <ul>
* <li> First implementation </li>
* </ul>
*/
public class StatefulHASessionInstanceCache
extends StatefulSessionInstanceCache
{
// Constants -----------------------------------------------------
// Attributes ----------------------------------------------------
// Static --------------------------------------------------------
// Constructors --------------------------------------------------
// Public --------------------------------------------------------
/**
* Remove an object from the local cache *without* any locking
* (synchronized, etc.) to avoid huge cluster-wide deadlock situations
* We have to unschedule passivation as well as the bean may be
* used on another node.
*/
public void invalidateLocally (Object id)
{
if (id == null) return;
try
{
getCache().remove(id);
}
catch (Exception e)
{
log.debug (e);
}
}
// Z implementation ----------------------------------------------
// AbstractInstanceCache overrides -------------------------------
/*
* Make less extensive use of global locking when state must be activated: it
* will most probably generate time-costly cluster-wide communication =>
* we must avoid globally locking the whole cache! Furthermore, The
* StatefulSessionInstanceInterceptor *already* locks concurrent access to the
* cache that targets the *same* SFSB identity
*/
public EnterpriseContext get(Object id)
throws RemoteException, NoSuchObjectException
{
if (id == null) throw new IllegalArgumentException("Can't get an object with a null key");
EnterpriseContext ctx = null;
synchronized (getCacheLock())
{
ctx = (EnterpriseContext)getCache().get(id);
if (ctx != null)
{
return ctx;
}
}
// If the ctx is still null at this point, it means that we must activate it
// => we don't lock the cache during this operation
// StatefulSessionInstanceInterceptor prevents multiple accesses for the same id
//
try
{
ctx = acquireContext();
setKey(id, ctx);
activate(ctx);
logActivation(id);
insert(ctx);
}
catch (Exception x)
{
if (ctx != null)
freeContext(ctx);
log.debug("Activation failure, id="+id, x);
throw new NoSuchObjectException(x.getMessage());
}
// FIXME marcf: How can this ever be reached? the ctx is always assigned
if (ctx == null) throw new NoSuchObjectException("Can't find bean with id = " + id);
return ctx;
}
// Package protected ---------------------------------------------
// Protected -----------------------------------------------------
// Private -------------------------------------------------------
// Inner classes -------------------------------------------------
}