Runtime monitoring Web services implemented in BPEL

As a service-based language, WS-BPEL (the Web service Business Process Execution Language) is widely adopted into enterprise solutions. However, because of the intrinsic flexibility and dynamism of the Web services it used, its behavior couldn't be foreseen until it is running, runtime monitoring is needed. The paper proposed a novel solution to the problem of monitoring Web services instances implemented in BPEL. The solution introduces Monitor Broker into traditional Web services architecture to access Web service runtime state information and calculate the QoS(Quality of service)property values, Monitor Broker architecture is devised with the support of Aspect Oriented Programming(AOP) that clearly separates the business logic of a Web service from its monitoring functionality. The initial implementation and experiment with a travel reservation service example shows that this approach is feasible and the monitoring cost is affordable.