Towards a Capability Model for Web Service Composition

Most approaches for Web service compositions focus on the technical level as they specify "how-to" achieve the composition instead of providing casual users with means to express "what-to" achieve their business objectives. This new mindset requires extending Web services with the concept of capability, which describes what a service can do to reduce the gap between Web services and business processes. In this paper, we propose a three-layer Web service capability model to capture objectives, to specify actions that achieve objectives, and establish links between capabilities. Based on this model, the capability matching process does not only discover Web services from high level requirements expressed by Semantics of Business Vocabulary and Business Rules (SBVR), but it also derives constraints on Web services.