| Web service composition is one of the key technologies for quickly building distributed applications based on SOA. Web service composition method is basically divided into two kinds, orchestration and choreography. orchestration realizes composition with the help of a center-control component, and is applied to the service interaction protocol known environment; and choreography realizes composition through message interactions between the services, and is applied to the service interaction unknown environment.The characteristics of Web service like heterogeneous, dynamic and self-description make Web service composition prone to protocol mismatches, that is process mismatches. Mediation technology is an effective way to solve this problem, this paper focuses on problem of process mismatches, the major work completed includes:1. It presents an orchestration mediation framework OMF, that is applied to the service interaction protocol known environment. OMF adopts a mediation approach considering the data dependencies, according to the presetting mediation rules, and the mismatch-specific types, addressing the runtime process mismatches problem, and through case study to verify OMF that can both support the control and data dependency caused mismatches.2. It presents an event-driven choreography mediation framework CMF, that is applied to the service interaction protocol unknown environment, CMF uses an executable action-based representation to describe the interaction protocol, and manages the interactive process based on event, using mediation agent encapsulating Web services, to achieve loosely coupled and autonomy of the mediation process mismatches.3. A prototype mediation system of choreography mediation framework CMF is designed and realized. Using message-oriented middle-ware technology, a mediation agent supporting event-driven mechanism is presented. Through a running case study to verify and analyze the functionality of CMF. Analysis shows that, CMF has stronger scalability without increasing the network traffic. |
