Viewing the logical message tree in trace output

Assume that you have configured a message flow that receives an XML message on a WebSphere® MQ queue in an MQInput node. The input message includes an MQRFH2 header. The message has the following content:

<Trade type='buy'
 Company='IBM'
 Price='200.20'
 Date='2000-01-01'
 Quantity='1000'/>

You can include and configure a Trace node to produce output that shows one or more of the trees created from this message: the message body, environment, local environment, and exception trees. If you choose to record the content of the message body, the Properties tree and the contents of all headers (in this example, at least an MQMD and an MQRFH2) are included. You specify what you want to be recorded when you set the Trace node property Pattern. You can use most of the correlation names to define this pattern (you cannot use those names that are specific to the Compute node).

Message body

If you want the Trace node to write the message body tree including Properties and all headers, set Pattern to ${Root}. If you want only the message data, set Pattern to ${Body}.

The trace output generated for the message tree of the preceding message with Pattern set to ${Root} would look like the following example:

Root
      Properties
         CreationTime=GMTTIMESTAMP '1999-11-24 13:10:00'          (a GMT timestamp field)
 
  ... and other fields ...
 
      MQMD
         PutDate=DATE '19991124'                                  (a date field)
 
         PutTime=GMTTIME '131000'                                 (a GMTTIME field)
 
  ... and other fields ...
 
      MQRFH
          mcd
          msd='xml'                                              (a character string field)
 
         .. and other fields ...
 
      XML
         Trade
          type='buy'                                             (a character string field)
 
         Company='IBM'                                           (a character string field)
 
         Price='200'                                             (a character string field)
 
         Date='2000-01-01'                                       (a character string field)
 
         Quantity='1000'                                         (a character string field)

Environment

To trace any data in the environment tree, set Pattern to ${Environment}. This setting produces output like the following example:

 (0x1000000)Environment = (
      (0x1000000)Variables = (
        (0x1000000)MyVariable1 = (
          (0x2000000) = '3'
        )
        (0x1000000)MyVariable2 = (
          (0x2000000) = 'Hello'
        )
      )
  ) 

To trace particular variables in the variables folder of the environment tree, you can use a more specific pattern, for example ${Environment.Variables.MyVariable1}. This setting returns the value only (for example, it returns just the value 3).

LocalEnvironment

To trace data in the local environment tree, set Pattern to ${LocalEnvironment}. The output you get is like the following example, which shows that a destination list has been created in the local environment tree:

(0x1000000)Destination = (
    (0x1000000)MQ                = (
      (0x1000000)DestinationData = (
        (0x3000000)queuename = 'MQOUT'
      )
    )
     (0x1000000)MQDestinationList = (
      (0x1000000)DestinationData = (
        (0x3000000)queuename = 'OLDMQOUT'
      )
    )
    (0x1000000)RouterList        = (
      (0x1000000)DestinationData = (
        (0x3000000)labelname = 'continue'
      )
      (0x1000000)DestinationData = (
        (0x3000000)labelname = 'custdetails'
      )
      (0x1000000)DestinationData = (
        (0x3000000)labelname = 'trade'
      )
    )
  )      

Another example, shown here, includes a WrittenDestination folder. This example represents a trace that has been written by a Trace node that is included after an MQOutput node, where the Out terminal of the MQOutput node is connected to a sequence of nodes including the Trace node. When an Out terminal is connected, the local environment is augmented with information about the action that the output node has performed.

(0x1000000)Destination        = (
    (0x1000000)MQ                = (
      (0x1000000)DestinationData = (
        (0x3000000)queuename = 'MQOUT'
      )
    )
  (0x1000000)WrittenDestination = (
    (0x1000000)MQ = (
      (0x1000000)DestinationData = (
        (0x3000000)queueName        = 'MQOUT'
        (0x3000000)queueManagerName = 'MQSI_SAMPLE_QM'
        (0x3000000)replyIdentfier   = X'414d51204d5153495f53414d504c455f1f442f3b12600100'
        (0x3000000)msgId            = X'414d51204d5153495f53414d504c455f1f442f3b12600100'
        (0x3000000)correlId         = X'000000000000000000000000000000000000000000000000'
	(0x03000000):GroupId          = X'414d512042524f4b45523220202020203f59934620001803'
      )
    )
  )
)

ExceptionList

To trace data in the exception list, set Pattern to ${ExceptionList}.

You can also view message structure in the message flow, and other information, when you use the flow debugger.