Messaging flow for JCA message-driven beans with IBM MQ as the messaging provider
The IBM MQ messaging provider uses your IBM MQ system as the provider. The IBM MQ messaging provider supports the JCA Resource Adapter (RA) mechanism. When you install a message-driven bean application you provide an activation specification.
The following figure illustrates the messaging flow for JCA message-driven beans that use IBM MQ as the messaging provider.
The z/OS® WebSphere® Application Server uses a two-part RA that supports "split" message-driven processing. The RA has a listener component which runs in the control region adjunct (CRA) and a dispatcher component which runs in each servant region (SR). The RA dispatcher component drives the application code. For some workloads, WebSphere Application Server can drive workload management directly from the CRA.
- When a message arrives at the destination, the IBM MQ RA listener receives and classifies a copy of the message.
- The IBM MQ RA listener invokes a control region (CR) function known as the SR aggregator.
- The SR aggregator uses z/OS workload management (WLM) to pass a message token (not the actual message) to an SR.
- The IBM MQ RA dispatcher uses the message token to receive the message and pass it to the onMessage method of the message-driven bean.
Optimization can allow the IBM MQ RA listener to invoke z/OS WLM directly, bypassing the SR aggregator processing in the CR.