Service-OrientedArchitecturesareapopulardevelopmentparadigmtoenabledistributedapplications constructedfromindependentwebservices.Whencoordinated,webservicesareaninfrastructure to fulfill dynamic and vertical integration of business. They may face frequent changes of both requirementsandexecutionenvironments.Staticandpredefinedservicecompositionsusingbusiness processexecutionlanguage(BPEL)arenotabletocaterforsuchrapidandunpredictablecontextshifts.

Nowadays applications are increasingly developed based on remote Web services and service composition has become a powerful novel development paradigm. Due to the fact that such applications in the context of Internet are deployed and executed in an open and dynamic environment, adaptability is one of the crucial requirements for developing such applications. In our previous work, we presented a variability-based approach to address the adaptability issue of service compositions, and developed the VxBPEL, an extension of BPEL with respect to variability. This paper presents a variability analysis tool for variability-based adaptive service compositions called ValySeC. ValySeC extracts the variation from service compositions specified using VxBPEL and provides a variation view. With the view, the designer can better understand variation points and the possible instances, and efficiently maintain the variation within service compositions. The paper presents the design and implementation of ValySeC using a case study to handle service compositions with variations to illustrate the main concepts.

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