Mule Quartz scheduler: process multiple messages

Question

This question was asked 4 months ago.

https://stackoverflow.com/posts/16241300/edit

Anyone?

"I have written a quartz code in mule flow to consume all the messages from queue every 5 minutes.

<quartz:inbound-endpoint jobName="abc" cronExpression="0 0/1 * * * ?" doc:name="Quartz">
               <quartz:endpoint-polling-job>
                     <quartz:job-endpoint ref="jmsEndPoint" />
               </quartz:endpoint-polling-job>
        </quartz:inbound-endpoint>

But this above code consumes only one message at a time even if there are 5 messages in the queue.

My requirement is to run a job every 5 minutes and consumes all the messages from queue.

Another requirements is to filter out duplicate messages using unique identifier from within the message payload.

Any help will be appreciated. "

EDIT: JMS endpoint

<jms:endpoint name="jmsEndPoint" queue="MyQueue" connector-ref="connector"/>

Answer 1

Queues are event based and are designed to return just one message (first in first out). In order to consume all messages from form a queue in a Mule flow, one approach is to create a custom component which will programmatically consume a jms message from a queue until there are no more messages.

In order to filter duplicate messages, consider using Mule's idempotent router:

http://www.mulesoft.org/documentation/display/current/Routing+Message+Processors#RoutingMessageProcessors-IdempotentMessageFilter

HTH

Answer 2

Looking at your code it looks like you will need to read it like this:

muleEventContext.requestEvent("MyQueue", -1);

If you want to filter on id you can do this:

<idempotent-message-filter idExpression="#[message:id]-#[header:foo]">
    <simple-text-file-store directory="./idempotent"/>
 </idempotent-message-filter>

Answer 3

In your Mule-config xml:

  <quartz:connector name="quartzConnector">
    <receiver-threading-profile
        maxThreadsActive="1" />
  </quartz:connector>

  <flow name="DelayedMessageProcessing">
    <quartz:inbound-endpoint name="qEP6"
                             cronExpression="${some.cron.expression}"
                             jobName="DelayedProcessing"
                             connector-ref="quartzConnector">
      <jms:transaction action="ALWAYS_BEGIN" />
      <quartz:event-generator-job />
    </quartz:inbound-endpoint

    <component class="com.something.myComponent" />
  </flow>

.. and the Java component:

package com.something;

import org.mule.api.MuleEventContext;
import org.mule.api.MuleException;
import org.mule.api.MuleMessage;
import org.mule.api.lifecycle.Callable;

public class MyComponent implements Callable {

    public Object onCall(final MuleEventContext muleEventContext) throws Exception {
        MuleMessage delayedMessage = fetchMessage(muleEventContext);

        while (delayedMessage != null) {
            //You might have to copy properties from inbound to outbound scope here..
            muleEventContext.dispatchEvent(delayedMessage, "some.jms.endpoint");
            delayedMessage = fetchMessage(muleEventContext);
        }

        return null;
    }

    private MuleMessage fetchMessage(final MuleEventContext muleEventContext) throws MuleException {
        return muleEventContext.requestEvent("some.delayed.jms.endpoint", 3000);
    }
}