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

Abstract

In this paper, we present XRL/Woflan. XRL/Woflan is a software tool using state-of-the-art Petri-net analysis techniques for verifying XRL workflows. The workflow language XRL (eXchangeable Routing Language) supports cross-organizational processes. XRL uses XML for the representation of process definitions and Petri nets for its semantics. XRL is instance-based, therefore, 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, the features also enable subtle, but highly disruptive, cross-organizational errors. On-the-fly changes and one-of-a-kind processes are destined to result in errors. Moreover, errors of a cross-organizational nature are difficult to repair. XRL/Woflan uses eXtensible Stylesheet Language Transformations (XSLT) to transform XRL specifications to a specific class of Petri nets, and to allow users to design new routing constructs, thus making XRL extensibe. 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.