/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt 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.messaging.core.plugin.postoffice.cluster;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.jboss.logging.Logger;
import org.jboss.messaging.core.Delivery;
import org.jboss.messaging.core.DeliveryObserver;
import org.jboss.messaging.core.Queue;
import org.jboss.messaging.core.Receiver;
import org.jboss.messaging.core.message.MessageReference;
import org.jboss.messaging.core.tx.Transaction;
/**
*
* This router first favours the failed over queue (if there is one) TODO revisit this
*
* Then it will round robin between the non queues.
*
* FIXME - none of the new failed over functionality has been tested!!
*
* @author <a href="mailto:tim.fox@jboss.com">Tim Fox</a>
* @author <a href="mailto:ovidiu@jboss.org">Ovidiu Feodorov</a>
* @version <tt>$Revision: 2319 $</tt>
*
* $Id: DefaultRouter.java 2319 2007-02-15 07:16:11Z ovidiu.feodorov@jboss.com $
*
*/
public class RoundRobinRouter implements ClusterRouter
{
// Constants ------------------------------------------------------------------------------------
private static final Logger log = Logger.getLogger(DefaultRouter.class);
// Static ---------------------------------------------------------------------------------------
// Attributes -----------------------------------------------------------------------------------
private boolean trace = log.isTraceEnabled();
// ArrayList<>; MUST be an arraylist for fast index access
private ArrayList queues;
private ClusteredQueue localQueue;
private int target;
// Constructors ---------------------------------------------------------------------------------
public RoundRobinRouter()
{
queues = new ArrayList();
}
// Receiver implementation ----------------------------------------------------------------------
public Delivery handle(DeliveryObserver observer, MessageReference ref, Transaction tx)
{
if (trace) { log.trace(this + " routing " + ref); }
if (!queues.isEmpty())
{
ClusteredQueue queue = (ClusteredQueue)queues.get(target);
Delivery del = queue.handle(observer, ref, tx);
if (trace) { log.trace(this + " routed to remote queue, it returned " + del); }
incTarget();
// Again, if the selector doesn't match then it won't on any others so no point trying
// them.
return del;
}
if (trace) { log.trace(this + " no queues to route to so return null"); }
return null;
}
// Distributor implementation -------------------------------------------------------------------
public boolean contains(Receiver queue)
{
//FIXME - what about failed over queues??
return queues.contains(queue);
}
public Iterator iterator()
{
//FIXME - this is broken - where are the failed over queuues?
return queues.iterator();
}
public boolean add(Receiver receiver)
{
return add(receiver, false);
}
public boolean remove(Receiver queue)
{
if (queue == localQueue)
{
localQueue = null;
}
if (queues.remove(queue))
{
if (target >= queues.size() - 1)
{
target = queues.size() - 1;
}
return true;
}
return false;
}
public void clear()
{
queues.clear();
localQueue = null;
target = 0;
}
public int getNumberOfReceivers()
{
//FIXME - what about failed over queues????
return queues.size();
}
// ClusterRouter implementation -----------------------------------------------------------------
public List getQueues()
{
return queues;
}
public boolean add(Receiver receiver, boolean failedOver)
{
ClusteredQueue queue = (ClusteredQueue)receiver;
if (queue.isLocal())
{
if (localQueue == null)
{
localQueue = queue;
}
else
{
throw new IllegalStateException("Local queue already exists");
}
}
queues.add(receiver);
return true;
}
public Queue getLocalQueue()
{
return localQueue;
}
// Public ---------------------------------------------------------------------------------------
public int size()
{
return queues.size();
}
public String toString()
{
return "Router[" + Integer.toHexString(hashCode()) + "]";
}
// Package protected ----------------------------------------------------------------------------
// Protected ------------------------------------------------------------------------------------
// Private --------------------------------------------------------------------------------------
private void incTarget()
{
target++;
if (target == queues.size())
{
target = 0;
}
}
// Inner classes --------------------------------------------------------------------------------
}