A Petri Net-Based Semantic Web Service Automatic Composition Method

Web service composition allows developers to create applications rapidly. But due to the tremendous growth in the number of Web services available, the Web service composition problem is still a challenging research issue. This paper introduces an automatic Web service composition method which considers both services’ input/output type compatibility and behavioral constraint compatibility. The services available are translated into a set of Horn clause-like rules. User’s input and output requirements are modeled as a set of facts and a goal statement in the Horn clauses respectively. Then Petri net is chosen to model the Horn clause set and T-invariant technique is used to determine the existence of composite services fulfilling the user’s input/output requirements. Two algorithms are presented for obtaining the Petri net models of the composite Web services which satisfy not only the user’s input/output requirements but also the user’s behavioral constraints.