A Refactoring Algorithm of Workflows Based on Petri Nets

A workflow net (WF-net for short) is a Petri net which represents a workflow. There are two important subclasses of WF-nets: extended free choice (EFC for short) and well-structured (WS for short). It is known that most actual workflows can be modeled as EFC WF-nets, and a cyclic WS is a subclass of a cyclic EFC but has more analysis methods. A sound a cyclic EFC WF-net may be transformed to an a cyclic WS WF-net without changing the observable behavior of the net. Such a transformation is called refactoring. We have proposed three refactoring rules. But those rules have been considered separately so far. In this paper, we proposed a new refactoring algorithm named "3 gate refactoring algorithm" by combining those rules. Furthermore, we applied the algorithm to a sample workflow, and confirmed the usefulness.