Invoking an adapter service using WebSphere MQ triggering

If the service requester is WebSphere® MQ-enabled, you are required to use the WebSphere MQ-CICS Bridge to pass the request message to the DPL stub program DFHMADPL.

There are multiple ways to start the WebSphere MQ-CICS bridge. This section explains how to start the CICS® bridge monitor program using WebSphere MQ triggering.

To start the CICS bridge monitor program using WebSphere MQ triggering, define the WebSphere MQ request queue with TRIGGER, TRIGTYPE(FIRST) INITQ('initiation queue') PROCESS('process') where:

The following steps describe how the runtime is invoked in asynchronous mode. See Figure 1 for an illustration of this process.
  1. The service requester sends a request message to the request queue. This causes WebSphere MQ to send a trigger message to the specified initiation queue.
  2. The WebSphere MQ trigger monitor program starts the CICS bridge monitor task, that is part of the WebSphere MQ-CICS bridge.
  3. The CICS bridge monitor browses the request queue. If a message has arrived, the CICS bridge monitor starts the CICS bridge link task, that is part of the WebSphere MQ-CICS bridge.
  4. The CICS bridge link task links to the DPL stub program, passing the request message in a COMMAREA, and waits for control to be returned. The request message that is passed to the stub program does not include the WebSphere MQ header data. The DPL stub program defines and runs a BTS process, passing the request message and waits for the adapter service processing to complete.
  5. If a reply message is required, the DPL stub program passes it to the CICS bridge link task in the COMMAREA. The reply message contains the application data and the message header.
    • In synchronous processing, if the WebSphere MQ-CICS bridge header (MQCIH) is not present in the request message, it will not appear in the reply message, except in the case of an error.
    • In asynchronous processing, the WebSphere MQ-CICS bridge header (MQCIH) structure is always included in the reply message.
  6. The CICS bridge link task responds to the service requester using an MQ PUT command if the MQMD ReplyToQ and ReplyToQMgr are loaded.
Figure 1. Invoking the run time via WebSphere MQ-CICS Bridge
Graphic illustrates the processing involved in invoking the run time via the WebSphere MQ-CICS bridge