Designing a self-adaptive and context-aware service composition system

Web service compositions run in changing environment where different context events can arise to affect the execution of services. In order not to make service execution affected by context events, context-aware service composition becomes one of the major research trends. Service providers can develop context-aware services which can adapt their behaviors dynamically to execution contexts. However, it burdens service providers because they have to keep in mind different execution contexts where their services could be used. In this paper, we design and implement a self-adaptive and context-aware service composition system which can adapt to changing execution contexts and make adjustments according to context events and user-defined personalized policies. It frees service providers from context handling which in turn becomes a task of our system. We use OWL to model context ontologies and extend the OWL-S service model to support context information. Policy is a user-defined adjustment strategy to guide the dynamic adaptation. Service consumers can submit their requests and get context-aware services. Our system can composite services according to service consumers' requests, execute services, monitor execution contexts and adjust its action when contexts change.