Research And Implementation Of Web Services Composition Transaction Coordination Framework

As a new computing model, Web Services is proposed in order to solve the problem ofheterogeneous distributed architecture. The goal is to make applications based on different platformsinteractive. Web services in distributed environment need to work with each other. To ensure that theresult of running composited web services is consistent and reliable is one of the most importantchallenges of Web Services. Transaction mechanism is an important way to solve such problems. Duoto some characteristics of Web Services such as autonomy, flexibility, heterogeneous and so on, thetraditional transaction semantics and protocols are proven to be inappropriate.WS-TX specifications define mechanisms for transactional interoperability between Webservices domains and provide a means to compose transactional services into Web servicesapplications. Because of lacking business process description mechanism, it is necessary to writecomplex code to define the business processes when using WS-TX to coordinate participants. WebServices Business Process Execution Language (BPEL) is an OASIS standard executable language. Itis flexible to use BPEL to define executable business processes, but it is lack of excellent transactionsupport such as atomic, organize cross transactions and forward recovery policy. So in this thesis, aWeb services composition transaction coordination framework based on extended BPEL and WS-TXis proposed. The main research works can be listed as follows.Firstly, duo to BPEL lacks of transactional semantics description mechanism, it must be extended.The definition of transaction flow is given based on WS-TX. According to transaction flow, a BPELtransaction semantics extending method is proposed. The transactional information can be used tocoordinate the business process.Secondly, a web services composition transaction coordination framework is proposed. Theframework combines the advantages of both WS-TX in the transaction coordination and BPEL inbusiness process design. The architecture, exception process policy, coordination Algorithm andbusiness process execution and so on are discussed.Finally, a prototype system of the coordination framework is developed by using Axis2andApache ODE. At last, the effectiveness of the framework is validated through a Web servicescomposition case study.