Essential Business Process Modeling

The Reference Model

The WfMC reference model^[*] describes at a high level the main pieces of a workflow management system. The model’s overall structure is depicted in Figure 7-1.

In Figure 7-1, the boxes represent components and the arrows interfaces. Here are its components:

Process definition tools

A process definition tool is an editor used by a business analyst or developer to compose a business process definition. Typically this tool is graphical, allowing the user to build the process by dragging and dropping boxes and arrows onto a design canvas. But the WfMC model does not require that the tool be graphical, nor does it prescribe a particular graphical representation language; there is nothing like BPMN (described in Chapter 6) in the WfMC world. The tool could just as well be a text editor. The key requirement is an ability to export the process definition in a standard form, which in turn can be executed by the workflow enactment service.

Figure 7-1. WfMC reference model

Workflow enactment services and constituent engines

An enactment service runs workflow processes. The service accepts as input process definitions imported from process definition tools. It creates and manages the overall execution of instances of these processes. A process does not run in isolation, and hence the enactment service provides open interfaces to external (client and invoked ) applications and administration ...