java - Connecting to IBM MQ using CCDT file in JMS

Question

I am trying to connect to IBM MQ using JMS and client channel definition table (CCDT). I was able to connect successfully to the QueueManager when i specify the MQ properties individually. But when i try to use CCDT file i get the below exception.

As client channel definition table (CCDT) is used to determine the channel definitions used by client applications to connect to the queue manager i didnt set QueueManager Name.

ERROR> com.ssc.ach.mq.JMSMQReceiver[main]: errorMQJMS2005: failed to create MQQueueManager for ''
javax.jms.JMSException: MQJMS2005: failed to create MQQueueManager for ''
    at com.ibm.mq.jms.services.ConfigEnvironment.newException(ConfigEnvironment.java:586)
    at com.ibm.mq.jms.MQConnection.createQM(MQConnection.java:2110)
    at com.ibm.mq.jms.MQConnection.createQMNonXA(MQConnection.java:1532)
    at com.ibm.mq.jms.MQQueueConnection.<init>(MQQueueConnection.java:150)
    at com.ibm.mq.jms.MQQueueConnectionFactory.createQueueConnection(MQQueueConnectionFactory.java:174)
    at com.ibm.mq.jms.MQQueueConnectionFactory.createConnection(MQQueueConnectionFactory.java:1066)

Iam using the .setCCDTURL(ccdt); method to set the CCDT URL.

private MQQueueConnectionFactory  mqQueueConnectionFactory = new MQQueueConnectionFactory();
         mqQueueConnectionFactory.setCCDTURL(ccdt);
         queueConnection = mqQueueConnectionFactory.createConnection(username, pwd);

When i try to connect using below configuration instead of the CCDT file it connects to the MQ.

         mqQueueConnectionFactory.setHostName(host);
         mqQueueConnectionFactory.setChannel(channel);
         mqQueueConnectionFactory.setPort(port);
         mqQueueConnectionFactory.setQueueManager(qManager);
         mqQueueConnectionFactory.setTransportType(1);

Do i need to set setQueueManager as well along with the CCDT file , as the exception says failed to create MQQueueManager for ''

Answer 1

The CCDT is not meant to be read in a text editor, it is a binary formatted file. One of the parameters in the CCDT for each CLNTCONN channel is QMNAME. Knowing what QMNAME is set to and how many CLNTCONN channels you have defined in the CCDT and what you want to accomplish will help figure out what value if any should be specified for with setQueueManager.

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If there is only one CLNTCONN channel then you could specify the following and it will connect using the single channel no matter what the QMNAME property is set to:

setQueueManager("*");

---

If there is more than one CLNTCONN channel in the file each with a different QMNAME specified, assuming the name matches the actual queue manager name listening on the host and port associated with the channel you would pass the queue manager name:

setQueueManager("QMGRNAME");

---

If there is more than one CLNTCONN channels in the file each with the same QMNAME specified where this name is not meant to reflect a actual queue manager name listening on the host and port associated with each channel, this is known as a queue manager group, this would be intended where you want the client to connect to any number of different hosts and ports and you do not need to know which queue manager you are connecting to, in this case you would pass the queue manager group name prefixed with a *:

setQueueManager("*QMGRGROUPNAME");

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Another variation of the above is if there is more than one CLNTCONN channels in the file each with an all blank (spaces) or NULL QMNAME specified, this is known as a queue manager group, this would be intended where you want the client to connect to any number of different hosts and ports and you do not need to know which queue manager you are connecting to, in this case you would pass the queue manager name as either a single space or nothing at all ``:

setQueueManager(" ");
//or
setQueueManager("");

The last use case above would likely work if you did not use setQueueManager at all.

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If you want to view the contents of the CCDT, you can use the runmqsc command that comes as part of the MQ v8 and higher client or server install.

For Unix ksh/bash shells use the following:

export MQCHLLIB=PATH/OF/CCDT
export MQCHLTAB=NAME_OF_CCDT
runmqsc -n

For Windows use the following:

set MQCHLLIB=PATH/OF/CCDT
set MQCHLTAB=NAME_OF_CCDT
runmqsc -n

Once the runmqsc program has started and displayed Starting local MQSC for 'NAME_OF_CCDT'. you can run the following command to see the channel details:

DIS CHL(*)

Below is a more specific command to narrow the number of fields returned:

DIS CHL(*) QMNAME CONNAME