CODEWITHSUNDEEP
javajmsibm-mq
Sricharan Anand
Sricharan Anand

Reputation: 37

IBM MQ JMS - Trying to read multiple messages at a time

I am trying to implement read ahead functionality for my client. They get a bunch of messages from IBM MQ Queues. Trying to read multiple messages at a time since they are non-persistent messages. I am unable to call the setReadAhead method provided by MQDestination.I tried finding any alternate way of doing this, but looks like no one uses ibm mq that much. Maybe I am doing it wrong. Using version ibm 9.1, and currently without the commented line in the code it reads messages one at a time.

Any help is appreciated!

Thanks

    void initMQConnection(String queueName) throws JMSException {
        MQQueueConnectionFactory factory = new MQQueueConnectionFactory();
        factory.setTransportType(JMSC.MQJMS_TP_CLIENT_MQ_TCPIP);
        factory.setQueueManager(jms_property.getProperty(queueManager));
        factory.setHostName(jms_property.getProperty(host));
        factory.setPort(jms_property.getProperty(port));
        factory.setChannel(jms_property.getProperty(channel));

        QueueConnection qConn = factory.createQueueConnection(username, password);

        QueueSession session = qConn.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
        Destination destination = session.createQueue(queueName);

        ((MQDestination) destination).setReadAheadAllowed(); // --> Unable to use this method (Cannot Resolve Method)

        MessageConsumer mc = session.createConsumer(destination);
        qConn.start();
    }

In the code where I am using messageConsumer, I call mc.recieve(1000);

Upvotes: 0

Views: 857

Answers (1)

Shashi
Shashi

Reputation: 15263

You can read/get only one message at a time, not multiple messages.

The read ahead feature enables underlying MQ client library to receive multiple non-persistent messages and buffer in it's memory. This is done to avoid MQ client making calls over the network to MQ server to receive one message at a time. The received messages are buffered in the MQ client memory and delivered one at a time to client application when a consumer.receive() call is made. Read more here on Read Ahead: https://www.ibm.com/docs/en/ibm-mq/9.3?topic=application-using-read-ahead-in-client

ReadAhead is a IBM MQ speicific function. You will need to cast the JMS Destination to MQQueue type. For example:

((MQQueue) destination).setReadAheadAllowed();

I don't see what packages have been imported, it appears that com.ibm.mq.MQDestination has been imported. setReadAheadAllowed is not a member of com.ibm.mq.MQDestination class. Instead it is a member of com.ibm.mq.jms.MQDestination class.

Upvotes: 1

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