Research And Implementation Of The Runtime Platform For QoS-driven Web Service Composition

Flexible business processes are a key success factor forenterprises to succeed in global markets. SOA architecturebased on Web Service is suitable for this flexible businessprocesses and application systems. Though the existing WebServices Composition, many business companies have begun toissue their professional business processes as Web Servicesonto the Internet to provide services for their partners. Withthe extensive applications of Web Service technology, there aremultiple Web Services with-the same function in the market.Enterprise users need to select the services with high QoS orhigheset cost performance and require the global QoS guaranteesof Web Services composition process. Services compositiontechnology and services composition running environment havebeen as the hotspots studied by industrial and academicorganizations.This paper analyzed the' existing running mechanism andfactors affecting the OoS of Web Services composition. Weintroduced a lightweight service-oriented middleware-WebJetServiceAgent, based on the agent mode, proposed a new WebServices composition running mechanism from the middleware andservices composition execution engine. The QoS-driven WebServices composition running platform was designed andimplemented. The running platform is based on the WS-Policyspecification. The extend policies such as Oos policy, serciceselection policy and recovery policy were designed andimplemented in the running platform. This platform was able to support QoS-driven services composition running and QoS-baseddynamic service selection at run-time, monitor functional andnon-functional attributes of services at run-time, performpolicy-driven fault operation such as retry or substitute inthe face of service invocation failure and guarantee reliableservice interaction; furthermore, a new multiple-threadexecution schedule model for BPEL4WS process, the extensibleand high-performance execution engine was designed andrealized according to the schedule model, and design acluster-based and extensible BPEL engine. The servicescomposition running quality was increased in terms of servicescomposition running environment.