Research And Implementation Of Web Services Composition Execution Engine Support With Dynamic Adjustment

Web Service, as a core technology of SOA, has strong ability to support the heterogeneous and distributed enterprise-class applications of Web Services composition, because of its coarse-grained, loosely coupled and cross-platform characteristics. BPEL is an XML-based, platform-independent business process modeling and implementation language. By interface manner, BPEL combine multiple independent Web services to form a complete process. Because of the complexity of business processes and the uncertainty of Internet resources, the process model keeps changing from time to time. The existing BPEL engines cannot provide strong support for dynamic adjustment of business process.To solve these problems, this thesis introduces the Web services technology and BPEL specifications, discusses the basic structure of the BPEL specification, and analyzes the architecture of BPEL engine, then proposes the shortcomings of the existing BPEL engines, and defines the design goals of Web Services Composition Execution Engine Support with Dynamic Adjustment (B-CWSEE). The thesis proposes the architecture of B-CWSEE, discusses the key issues in B-CWSEE, including BPEL parser, state transition and scheduling of process instance, service invocation, process instance dynamic adjustment and process management. To solve the scheduling issue of process instance, the thesis proposes a separation mechanism to separate process scheduling from process execution. To meet the requirements of dynamic adjustment implementation in B-CWSEE, the thesis analyzes the dynamic adjustment strategy and the state migration issue of process instance, and then proposes a dynamic adjustment mechanism in B-CWSEE. At last, the thesis introduces the detailed implementation of B-CWSEE.