A Mediator Based Approach For Services Composition

Web services are becoming one of the main technologies for designing and building complex inter-enterprise business applications. Usually, a business application cannot be fulfilled by one Web service but by a combination of several ones. Hence, there is an obvious need for mechanisms allowing Web services composition. In this paper, we are interested in the automatic composition of Web services. Our composition framework is based on the coordination of Web services having the capability to communicate via the exchange of messages. Web services are modeled as conversational automata, where transitions are possibly guarded according to the values of exchanged or produced data. If the coordination does not satisfy the business application, we synthesize a new service called mediator. The mediator aims at generating the missing messages which are required to complete the cartesian product so that it mimics the goal service representing the business application to implement.