From Web Service Artifact to a Readable and Verifiable Model

Models of Web service compositions that are both readable and verifiable will benefit organizations that integrate purportedly reusable Web services. Colored Petri nets (CPNs) are at once verifiable and visually expressive, capable of presenting subtle flaws in service composition. Constructing CPN models from business process execution language (BPEL) artifacts had been a manual process requiring human judgment. Building on results from the workflow community, we automate the mapping of artifacts written in BPEL to models used by CPN Tools - a formal verification environment for development, simulation, and model checking of colored Petri nets. We extend related work that already converts BPEL to Petri nets, to reflect hierarchy and data type (color in CPN terminology), while improving model layout. We present a prototype implementation that mines both a BPEL artifact and the Petri net generated from it by an existing tool. The prototype partitions the Petri net into subnets, lays them out, colors them, and generates their XML file for import into CPN tools. Our results include depictions of subnets produced and initial simulation results for a well-known case study.