CODEWITHSUNDEEP
javajmsmuleibm-mqmq
Pratik Shelar
Pratik Shelar

Reputation: 3212

COD received has correlationID and body as null

We are sending a message to Websphere MQ Queue. While sending the message we are setting the REPLY TO QUEUE NAME and JMSCOrrelationID. We also set the USER IDENTIFIER. The code snippet is as follows.

Message  msg = session.createTextMessage((String) message);
Destination codeDestination = session.createQueue("queue://" + replyToQueueMgr + "/" + replyToQueueName);
msg.setJMSReplyTo(codeDestination);
msg.setIntProperty(JmsConstants.JMS_IBM_REPORT_COD, MQC.MQRO_COD);
msg.setJMSCorrelationID(msgCorrelId);
 msg.setStringProperty(JmsConstants.JMS_IBM_MQMD_USERIDENTIFIER, "abc");
producer.send(msg);

Please note that we have ensure that all the fields which we set are not null. Also the user abc is a valid user because if not then the CODs should go to DEAD LETTER QUEUE but there are no messages in it. Still after the message is picked up we get a COD which has JMSCorrelationID as null. In COD Processor we are listening on the replyToQueuename.

String correlationID = (String)eventContext.getMessage().getInboundProperty("JMSCorrelationID");

On checking above correlation ID is null. ALso the message payload is of {null_payload} type of NullPayload class of mule. I know that body would be NULL because we set MQC.MQRO_COD. But I dont undertand how the correlationId got wiped out.

Please advise if there is any configuration at the Webview MQ end whih could cause such a behaviour? Or is there something missing in the way we are setting the header properties?

UPDATE

The queue that we are sending the message to with COD information is an alias to a TOPIC. There are 2 subscribers to this TOPIC and we observed that there were instances where we received multiple COD's when both the subscribers picked up the messages. Is there any way to ensure that the TOPIC sends a single COD after all the subscribers have picked up the message? Could this QM setup be the cause of the COD with null?

Upvotes: 0

Views: 1987

Answers (2)

Pratik Shelar
Pratik Shelar

Reputation: 3212

The issue is not with MQ configuration but with Mule endpoint configuration. The COD which were sent with nullpayload were actually sent by my own mule application jmsRepyToHandler. There is some default configuration in Mule which seems to be causing this behavior.

Analysis

  • Application sends a message to the Queue which is alias to a TOPIC with two subscribers
  • Once both the subscribers consume the message we get 2 COD as expected.
  • These COD are consumed by my MULE application and after processing the MULE application again sends COD to same queue with null correlation Id.

UPDATE: Mule Fix to avoid default ReplyTo

For the fix you need to override getReplyToHandler method of Mule JMSConnector as follows

if (disableReplyTo) {
  return new DisableJmsReplyToHandler(this, getDefaultResponseTransformers(endpoint));
}else {
  return super.getReplyToHandler(endpoint);
}

Set the property disableReplyTo as true so that above code provide DisableJmsReplyToHandler instead of the default one.

Upvotes: 0

Morag Hughson
Morag Hughson

Reputation: 7525

User Identifier

When a message is published, each subscriber gets a copy of the message with a unique message ID and with the identity context fields in the MQMD (UserID, AccountingToken, ApplIdentityData) all set to the subscriber's context. So it doesn't matter what you set in the MQMD UserID of the message you publish, all the copies will have the subscriber user ID in them. This user ID will, by definition, exist where he subscriber is so the CODs will be able to be put.

Correlation ID with Pub/Sub

You can ensure the correlation ID from the publisher is sent all the way through to the subscriber, by ensuring the subscription is made using MQSO_SET_CORREL_ID and setting the MQSO SubCorrelId to MQCI_NONE.

One COD for multiple messages

Since there are multiple independent messages, each with the COD Report Option set, you will get multiple report messages. There is no setting to combine these, however you could write an intermediate application to combine then if your main application wants only one.

Passing Correl ID back in a Report Message

By default the report option will send back the message ID in the Correl ID of the report message. If you want to have the Correl ID passed back, you should use MQRO_PASS_CORREL_ID.

Further Reading

Upvotes: 2

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