An Approach Based on Hierarchical Petri Nets for the Verification of Interconnected BPEL Processes

This article describes an MDE approach for transformation from BPEL specifications to WF-nets models for verifying behavioral properties on IOWF (Inter-Organizational Workflow) processes. The authors consider WF processes specified with BPEL and interconnected together according to specific cooperation patterns. They define a specific class of Petri nets called Hierarchical WF-nets (HWN) in order to formally check the “soundness” property on IOWF process models. For that, their verification approach is defined around three main phases: (i) recovery of the BPEL file(s) and generation of process tree(s), (ii) transformation from BPEL to WF-nets (resp. HWN) models using mapping and transformation rules and (iii) verification of the “soundness” property on the models obtained. They particularly define and implement a set of specific transformation rules which are closely linked to the interconnection rules attached to each cooperation pattern. Also, to show the feasibility of their verification method, the authors developed a “WF-Checking” tool which allows the implementation and testing of the proposed approach.

CTL Model Checking of Web Services Composition based on Open Workflow Nets Modeling

Web services composition (WSC) has an enormous potential for the organizations in the B2B area. In fact, different services collaborate through the exchange of messages to implement complex business processes. BPEL is one of the most used languages to develop such cooperation. However, it has been proved that its use is complex and can require some expertise in XML syntax. Even its graphical representation is not evident to handle. This is why the authors propose to model Web services using oWF-nets, a subclass of Petri nets, and then, to translate them to BPEL. Whilst, a WSC is with added value only if the involved services are compatible. So in this context, across the translation proposed the researchers develop a verification layer of the WSC compatibility. Hence, they propose a framework named D&A4WSC which allows to model the WSC by oWF-nets, to check their compatibility with the model checker NuSMV and to translate them if they are compatible in BPEL processes using the oWFN2BPEL compiler. D&A4WSC permits, furthermore, to formally analyze a BPEL process.