Essential Business Process Modeling

WfXML

One of the goals of the WfMC reference model is to achieve interoperability in heterogeneous processes , or processes that span multiple enactment services, possibly crossing company boundaries and workflow vendor implementations. Heterogeneous processes are common in business-to-business communication. The travel reservation system considered in the section on XPDL, for instance, requires that a travel agency process start airline, hotel and car rental agency booking processes and wait for their completion.

Conceptually, the problem to be solved is to coordinate the activities in one process with those in another, as in the example in Figure 7-6, in which the Supplier process calls the Warehouse process and also synchronizes its activities.

Figure 7-6. A heterogeneous process spans Supplier and Warehouse

The WfMC reference model lists several heterogeneous patterns , described in Table 7-2.

Table 7-2. WfMC heterogeneous patterns

Pattern	Description
Chained	An activity in process A triggers an activity in process B.
Nested	An activity in process A triggers process B to start. Process A waits for the completion of B before resuming.
Synchronized	Process A blocks and waits for process B to trigger it.

WfXML Specification

WfMC’s interenactment protocol is a web services model called WfXML.^[*] WfXML is built on Asynchronous Web Services Protocol (AWSP) , a specification from the OASIS group (the ...