Aspect Separation in Web Service Orchestration: A Reflective Approach and its Application to Decentralized Execution

Web service orchestration is becoming widely spread for the creation of composite Web services using standard specifications such as BPEL4WS. The myriad of specifications and aspects that should be considered in orchestrated Web services are resulting in increasing complexity. This complexity leads to software infrastructures difficult to maintain with interwoven code involving different aspects such as security, fault tolerance, distribution, etc. In this paper, we present ZenFlow a reflective BPEL engine that enables to separate the implementation of different aspects among them and from the implementation of the regular orchestration functionality of the BPEL engine. We illustrate its capabilities and performance exercising the reflective interface through a decentralized orchestration use case.