Research And Implementation Of Services Composition Technology Based On Business Process Execution Language

As a new technology in program design fields, Web Services can make different platforms interact with each other, implement remote procedure call between applications by Internet. But simple service can hardly satisfy the increasing business demand, it is meaningful for the development and application of Web Services to construct a Web Services composition frame.On the basis of analysis Web Services and existing Web Services composition technologies, utilizing the good Web Services composition ability of BPEL(Business Process Execution Language), aimed at improving the BPEL's ability of abnormity restoration, B_WSCS (BPEL-Based Web Services Composition System) is presented. The architecture of B_WSCS is described, the Web Services composition flow and run-time abnormity restoration process are explained, the design techniques of process model registration center, agent and engine are presented.To improve the ability of abnormity restoration, ensure the convenience of services composition, B_WSCS not only conforms existing compensation measures, but also affords a new abnormity restoration method that engine executes replaced service when abnormity occurs by UDDI registration center, agent, engine, existing BPEL criterion and so on. A flexible replaced service chosen strategy is presented by extending existing BPEL. So it isn't necessary to terminate the process when abnormity occurs in a service during run-time.Testing result shows that B_WSCS has good Web Services composition ability as BPEL, as well, it resolves the problem of the BPEL limitation that BPEL fault handler and compensation handler are only aimed at"undo"operation, and it improves the abnormity restoration ability of business process.