org.mule.routing.RoundRobinRoutingStrategy Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of mule-core Show documentation
Mule server and core classes
There is a newer version: 3.9.0
/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.routing;


import org.mule.api.MessagingException;
import org.mule.api.MuleContext;
import org.mule.api.MuleEvent;
import org.mule.api.MuleException;
import org.mule.api.processor.MessageProcessor;
import org.mule.api.routing.RoutePathNotFoundException;
import org.mule.config.i18n.CoreMessages;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Routing strategy that divides the messages it receives among its target routes in round-robin
 * fashion. The set of routes is obtained dynamically using a {@link org.mule.routing.DynamicRouteResolver}.
 * 
 * This includes messages received on all threads, so there is no guarantee
 * that messages received from a splitter are sent to consecutively numbered targets.
 */
public class RoundRobinRoutingStrategy extends AbstractRoutingStrategy
{

    private final IdentifiableDynamicRouteResolver identifiableDynamicRouteResolver;
    private Map roundRobinState = new HashMap();

    public RoundRobinRoutingStrategy(final MuleContext muleContext, final IdentifiableDynamicRouteResolver identifiableDynamicRouteResolver)
    {
        super(muleContext);
        this.identifiableDynamicRouteResolver = identifiableDynamicRouteResolver;
    }

    @Override
    public MuleEvent route(MuleEvent event, List messageProcessors) throws MessagingException
    {
        if (messageProcessors == null || messageProcessors.isEmpty())
        {
            throw new RoutePathNotFoundException(CoreMessages.noEndpointsForRouter(), event, null);
        }

        String id = identifiableDynamicRouteResolver.getRouteIdentifier(event);
        Short nextMessageProcessor = 0;
        synchronized (this)
        {
            if (roundRobinState.containsKey(id))
            {
                Short lastMessageProcessor = roundRobinState.get(id);
                nextMessageProcessor = (short) (lastMessageProcessor + 1 >= messageProcessors.size() ? 0 : lastMessageProcessor + 1);
                roundRobinState.put(id, nextMessageProcessor);
            }
            else
            {
                roundRobinState.put(id, (short) 0);
            }
        }

        MessageProcessor mp = messageProcessors.get(nextMessageProcessor);

        MuleEvent eventCopy = cloneEventForRouting(event, mp);
        try
        {
            return mp.process(eventCopy);
        }
        catch (MuleException me)
        {
            throw new RoutingFailedMessagingException(CoreMessages.createStaticMessage("Error processing event"), event, me);
        }
    }

    private MuleEvent cloneEventForRouting(MuleEvent event, MessageProcessor mp) throws MessagingException
    {
        return createEventToRoute(event, cloneMessage(event, event.getMessage(), getMuleContext()), mp);
    }
}