CPN-based Web Service Composition Technology

In many cases, a single Web service can´t meet the needs of users, so Web service composition becomes an important issue. As the Web service increases rapidly, it is more and more important to find an auto composition technology. At present most CPN-based composition technologies establish CPN model, but these methods don´t take full advantage of CPN tools to resolve the composition. In this paper, we firstly give the CPN model of the whole of the Web services according to the match of service interface. In our model, a transition represents an operation and a place represents an input or an output. Every input and output isn´t semantically ambiguous by ontology. Every places´ colorset is bool. Secondly, we calculate the state space of the CPN model. Thirdly, we use node functions of the state space in CPN tools to find the target nodes each of which make every target place have a true value. Then a path must be figured out from the initial node to the target node by CPN Tools arc functions. The Web service sequence represented by this path is the composition service.