Towards Context-aware Service Composition Based On BPEL

With Service-Oriented Computing (SOC), resources distributed in the Internet are encapsulated as publically-accessible Web Services, Which can be further orchestrated to make composite services with well-defined processes (also known as workflows). This process is called web service composition. However, in the open environment, service compositions often need the ability of dynamically changing its process in or-der to adapt to the ever-changing user requirements and system environments. As the mainstream industry standard in the field of service composition, Business Process Ex-ecution Language (BPEL) still lacks this ability. Furthermore, the range of context is broadened and the adaptability to context is emphasized due to the development of pervasive computing, which requires BPEL the ability of context-awareness more than ever to get closer to the physical world and to adapt more kinds of context.In this paper, we research the technique on BPEL towards context-awareness. Our study area is related to modeling context-awareness, process dynamic update and process engine technique. The contribution of our work includes:· An approach of modeling context-awareness is proposed based on BPEL. Ac-cording to the relationship of services and physical objects, we focus on the main concerns of service composition, give our model elements to make use of physical context. In our approach, we make effort to avoid the intersection of business data and context data.· An overall strategy to handle the process adaption in different scenarios based on our modeling approach is proposed, which improves the adaptability of service composition described by BPEL.· A BPEL process engine supporting context-awareness is implemented based on Java Business Process Management (JBPM). The implementation consists of two stages. First, we extend JBPM to support the dynamic adaptation of process. Then, we modify the process definition parse module according to the extension of BPEL, and add modules to provide context-awareness ability.· To prove the effectiveness and feasibility of our modeling approach, we design a service composition process based on an emergency relief scene, and show the process of modeling and execution by simulating the environment.