A Formal Specification for Web Services Composition and Verification

Due to the promising features of Web services, their deployment and research are booming. Among them, various techniques for Web service composition have been developed. In this paper, we propose a new composition framework. We use automata to describe behaviors of Web services. Each of underlying Web services can interact with others through asynchronous messages passing according to its interaction role (client or server). All these messages are recorded by a virtual global observer and the observation result is just the composition conversation of Web services. We also develop a formal a top-down verification mechanism on this framework and provide some realizable conditions for a successful composition