XRL/Woflan: Verification and Extensibility of an XML/Petri-Net-Based Language for Inter-Organizational Workflows

Internet-based technology, E-commerce, and the rise of networked virtual enterprises have fueled the need for inter-organizational workflows. Although XML allows trading partners to exchange information, it cannot be used to coordinate activities in different organizational entities. Therefore, we developed a workflow language named XRL (eXchangeable Routing Language) for supporting crossorganizational processes. XRL uses XML for the representation of process definitions and Petri nets for its semantics. Since XRL is instance-based, workflow definitions can be changed on the fly and sent across organizational boundaries. These features are vital for today’s dynamic and networked economy. However, these features make cross-organizational workflows susceptible to errors. In this paper, we present XRL/Woflan, a software tool using state-of-the-art Petri-net analysis techniques for verifying XRL workflows. The tool uses XSL (Extensible Style Language) Transformations (called XSLT) to translate XRL specifications to a specific class of Petri nets called workflow nets. The Petri-net representation is used to determine whether the workflow is correct. If the workflow is not correct, anomalies such as deadlocks and livelocks are reported. This approach also makes XRL extensible. Therefore, new, application-specific workflow patterns can be created and incorporated into XRL by expressing their semantics in XSLT.