Towards context-adaptable Web service policies

We propose in this paper a new approach to achieve highly adaptable Web services through context-adaptable Web service policies. A Web service policy is a set of rules that defines the capabilities and requirements of a Web service as well as governs the runtime behavior, quality and result of the Web service. Our Web service policies are superbly adaptable in the sense that we specify context for both policies and rules to make the policies context-adaptable at both policy and rule levels. The main contributions of our approach include: i) an innovative WSPL (Web Service Policy Language) extension to allow context specification at both policy and rule levels; and ii) a tool that supports the development of aspect oriented policies, including an option to translate WSPL policies into aspect oriented policies. These policies can then be statically woven into composite Web services (e.g. a BPEL process). The synergy between context, policies and aspects allows to increase the level of adaptability of Web services at different levels of applications.