Toward a formal approach to composite Web service construction and automation

Based on business processes, composite Web services combine the offerings of two or more Web services to achieve the desired business goals. Several candidate standards have been proposed, providing a foundation for composite Web service specifications. However, at a higher level, there is no framework that supports composite Web service construction and automation. We propose a framework that facilitates the visual design, validation and automation of composite Web services. The framework is based mainly on Web service composition graph (WSCG), the underlying formalism for composite Web services. Using graph grammar and graph transformation defined on WSCG, the static topological structure of a composite Web service can be described in an intuitive way and the automation of the constructed composite Web services is also facilitated with a sound formal semantic basis. We also outline the design and implementation of a prototype for the proposed framework