Improvement And Optimization Of The Web Services Composition Execution Engine WebJetFlow

Nowadays,Web Services have become the mainstream technology of SOA,because more and more enterprises need to publish existing applications by the way of Web Services under the SOA architecture and Web Services framework.They also want to integrate Web Services of their partners to realize function integration and provide new composition services.Composition service process consists of multiple component Web Services and is described by BPEL4WS.Composition service process is deployed on BPEL4WS execution engine which invokes the component Web Services according to the order orchestrated beforehand in order to perform the execution of the process.Whether the QoS of Web Services Composition Execution Engine can be guaranteed is the key point of whether the composition services can be practicable.This thesis has analyzed the current execution mechanism of Web Services composition execution engine--WebJetFlow.Although WebJetFlow is a multi-thread BPEL4WS execution engine,it doesn't include an effective thread management mechanism.Therefore,with the long time execution of WebJetFlow,there will be a large scale of anonymous thread generated which have a bad influence on execution efficiency.Based on the above reasons,dual-thread pool model has been introduced into WebJetFlow proved to enhance the execution efficiency.Because of the different reasons in the process of service realization, some Web Services providers may take a long time to respond,this may lead to transmission delay.So Iong-lifecycle service invocation have been transformed to asynchronous invocation to decrease the time that the engine waiting for the response from the Web Services provider,in order to improve the engine execution efficiency of accessing the process concurrently.All of the current execution models of mainstream BPEL4WS engines are "best effort" model and they don't consider the level of QoS for any service requests,thus,the engine will be very busy,even refuse to accept the service requests under the condition of overload.Consequently, WebJetFlow has been imported into the mechanism of service classification in order to support the SLA agreement.According to the QoS levels of the SLA agreement which is signed between the engine and the client,the resources of WebJetFlow will be scheduled.The requests of high SLA level will get a high priority to be dealt with under the QoS constraints;this can make the important requests win better services and make the execution scenes of composition services get closer to the real business logic.By improving the design,perfecting and optimizing the execution mechanism of WebJetFlow,we guarantee the QoS of the execution of composition services over the internet.