Research And Implementation Of Web Services Transaction

Web Services transaction should guarantee the dependability and consistency of multiple Web Services' compositional results, and can solve the run-time errors. Current Web Services transaction protocols, such as WS-Coordination, WS-AT and WS-BA by IBM and Microsoft, and BTP by OASIS, can not provide accurate transactional semantic definitions, which badly block the transactional implementation. These protocols relax the ACID properties of conventional transactions and redefine the transactional properties in the loosely coupled context. However, there are some problems in these protocols, such as describing simple, different means etc. Therefore, while implemented, the protocols need to be formally analyzed, validated, and then supplemented in order to assure their improvement and correct implementation.Based on the polyadicπ-calculus, we deeply study the Web Services transaction protocols: WS-AT and WS-BA, and propose an implementation framework of transactional workflow. The contributions of this dissertation include:Firstly, we analyse the kinds of transaction in detail, which can be sorted to conventional transaction, mobile transaction and Web Services transaction on time order. We summarize the current research status of the transaction studied formally, which can includes three methods: one based on Petri Net, one based on Process Algebra and one based on Temporal Logic, and further we sum up the pro & con of each one. We also deeply investigate the current research status of Web Services transaction implementation.Secondly, the WS-AT with the simple State Transition Table and Chart can not describe the complex coordinate actives clearly when coordinator are communicating with multiple participants. Therefore, we describe WS-AT formally withπ-calculus, apply it to rule the coordinators' and participants' activities, and then confirm that WS-AT satisfies the atomic property through check command of the weak bisimulation of MWB. Thirdly, because WS-BA adopts simple State Transition Table and Chart and can't describe the transition of interior states, the coordinators don't know how to coordinate the outcomes of participants when having multiple participants so that we have extended the WS-BA BusinessAgreementWithParticipantCompletion protocol to BAPC. Then the formal model of BAPC protocol is established with polyadic n-calculus, and the long running transactional properties including durability, eventuality and local atomicity of the BAPC protocol are proved.Lastly, we not only analyze the WS-AT and WS-BA, but also propose the implementation framework of transactional workflow: TxWebJetFlow, which is based on the two protocols above and built on the Web Services compositional workflow engine--WebJetFlow. TxWebJetFlow can guarantee the transactional properties of compositional Web Services by extending the business process execution language BPEL and the original data structure of WebJetFlow, and adding coordinated mechanism of atomic and business transaction.In conclusion, we have perfected the Web Services transaction protocols by formal method, and have proposed implementation framework of transactional workflow in this dissertation. We argue that our contributions listed above are valuable for the development of compositional Web Services and the execution platform in both theory and practice.