A Dynamic Reconfigurable Web Service Composition Framework Using Reo Coordination Language

Web services are self-contained, modular units of application logic which provide business functionality to other applications via Internet connections. Several models have been used to compose Web services which are mainly served at specification level and provide static data dependent coordination processes. Hence they can not support reconfigurable dynamic coordination processes in which participant Web services and the coordination process itself will not be known explicitly prior to execution and would be determined dynamically at run time. In this paper we present a framework to coordinate Web services using Reo coordination language. Reo is a channel-based exogenous coordination language which has a formal basis and supports loose coupling, distribution, dynamic reconfiguration and mobility. Given that Web services are inherently loosely coupled and primarily built independently, the channel-based structure of Reo and its reconfigurability will provide a reconfigurable coordination mechanism for Web service composition. The proposed approach is a distributed dynamic orchestration framework which uses Reo channels as a communication means between Web services and benefits from Reo reconfiguration property to provide a dynamic coordination process. Due to data independence property of Reo, the proposed model is a data neutral framework which is mainly focused on coordination. In this paper we also present a number of case studies by using the proposed framework and investigate its pros and cons through these case studies.