基于补偿业务生成图的组合服务异常处理方法研究

为提高组合Web服务执行的一致性、可靠性,提出一种基于补偿业务生成图的组合服务异常处理方法.基于业务流程中任务间补偿依赖关系,讨论了补偿业务生成图的自动生成问题.重点讨论了补偿任务、补偿目标和服务转让应用模式,并相应地介绍了支持框架和相关技术.在此基础上设计了补偿依赖关系、补偿业务生成图的自动生成及组合服务执行过程中异常处理算法.当业务流程出现异常采取向前或向后恢复处理时,该方法在保证补偿实现的同时,兼顾补偿服务不存在或补偿服务代价过高的问题,提高了业务流程执行过程中的自动化水平和自适应能力.仿真结果证实,该方法保证了异常发生时组合服务执行的可靠性和一致性.

Research on Exception Handling of Composite Services Based on Compensation Business Process Graph

To enforce consistency and reliability of composite Web services at run-time, this paper proposes a novel approach based on compensation business process graph to addressing the problem of exception handling in composite services. According to compensation dependencies among tasks in business processes, the automatic generation of compensation business process graph is proposed. Compensation task, compensation goal and application model of service transfer are discussed in detail, and the relevant supporting infrastructure and technique are introduced. Based on this, algorithms for automatic generation of compensation dependency and compensation business process graph, as well as algorithm for exception handling during execution of composite services, are proposed. When exceptions are handled with forward- or backward-recovery methods during execution of composite services, the approach can guarantees compensation achieving, and also gives consideration to the problem that there are no compensation services or the cost to achieve compensation is too expensive. The mechanism described here improves self-adjustability and stability of composite services in the course of deployment and execution. Simulations prove that the approach can efficiently guarantee the consistency and reliability of composite services at run-time.