CODEWITHSUNDEEP
mulemessage-queuemule-component
Jeet
Jeet

Reputation: 321

Custom component to read messages from queue

I'm using Mule 3.3.1

I am trying to write a Component that reads all available messages from queue, which I intend to be polled using a Quartz scheduler.

Here is my code.

    @Override
public Object onCall(MuleEventContext muleEventContext) throws Exception {
    MuleMessage[] messages = null;

    MuleMessage result = muleEventContext.getMessage();
    do {
        if (result == null) {
            break;
        }
        if (result instanceof MuleMessageCollection) {
            MuleMessageCollection resultsCollection = (MuleMessageCollection) result;
            System.out.println("Number of messages: " + resultsCollection.size());
            messages = resultsCollection.getMessagesAsArray();
        } else {
            messages = new MuleMessage[1];
            messages[0] = result;
        }
        result = muleEventContext.getMessage();
    } while (result !=null);
    return messages;
}

Unfortunately, it loops indefinitely on the first message. Thoughts?

Upvotes: 1

Views: 432

Answers (1)

user1760178
user1760178

Reputation: 6647

The onCall() method provided in the post is going to loop infinitely because 

muleEventContext.getMessage()

always returns a MuleMessage. And so the loop will go in infinitely.

MuleEventContext object here is not an iterator or stream where the pointer points to next element after reading current element.

In order to read all the avialable messages from the queue. You can have a JMS inbound to read by polling on the queue and read all the messages. But remember each message on the queue will be one iteration(one message) from your JMS inbound.

If you want to gather all the Queue messages as a collection of objects and then proceed, then that is a different story. That cannot be done with your component code.

If you intend to gather all your messages as a collection and then start processing then try using something like collection-aggregator of mule at your inbound.

Hope this helps.

Upvotes: 2

Related Questions