EXCEPT FOR THE “Hello, World!” program, no program has been written as many times by as many people as the Message Broker. Seemingly every vendor and every consultant in the integration space has posited Message Broker as that central enterprise hub through which the message-oriented communications of all systems ought to pass. Without it, every enterprise is a mess of heterogeneous point-to-point cross-talk. But if the individual systems can be programmed to talk to the broker, the broker—a smarter communicator than other system out there—guarantees to relay the message to the right parties. Every company knows how messy application integration can be, and is naturally attracted to the idea of a broker.
This chapter begins by exploring the nature of a BPM-powered Message Broker that, running on message-oriented or service-oriented middleware, uses processes to drive routing logic. The bulk of the chapter is an example of a set of brokering processes, designed using BPMN notation (using ITpearls’ Process Modeler plug-in for MS Visio) and implemented in BPEL (using Oracle BPEL Process Manager, as described in Chapter 10).