A method for composing process of nondeterministic Web services

Web services have been common technologies for providing services over the Internet. In the future, it is expected that a usage model that autonomously integrates services will become ordinary in, for example, B2B integration. However, such method of executing pre-defined process lacks flexibility because a service requestor must know in advance the interface of all integrated services. Accordingly, there is a need for a method that composes a process from the requestor's requirement independent of the interface of services. This paper proposes the architecture and a method for composing a process automatically. Our approach is formulating Web services function and a requestor's requirement as the transitions of his state by means of situation calculus and calculating what process is matched with the requirement. In our method, we model message-oriented execution of service. Moreover, our method is capable of composing not just a sequential process but also a process including conditional choices. Therefore, our method has the basic feature to be able to compose nondeterministic Web service.