Research And Application Of Transaction Based Web Service Composition

Web service composition as a typical Internet-based service composition form, is widely attentioned. Due to the loosely coupled characteristic of web services, to ensure the proper interaction between each other web services and consistency of the results, it is necessary to provide the transaction mechanisms. At present, the transactional processing of composite web services has become a research hotspot.For the long running characteristic of web service transaction, this paper proposed a universal composition web services description model (UWSC-NTM) which supported the transactional mechanism. This model support dynamic transaction-based Web service composition, and has a wealth of execution semantics to support a complex Web service composition. In this paper, using the formal methods to verify the execution semantic of UWSC-NTM and proposed the well-formedness criteria. Based on the model, design and implement a composite service transaction recovery algorithm. The algorithm introduced the transaction executor and transaction coordinator concept, proposed CSQ based forward recovery algorithm and HST based backward recovery algorithm, different from the traditional centralized model of a single coordinator approach, using a distributed transaction coordinated approach to solve the single-coordinator of the performance bottleneck and single point failure problems and improve the success rate of the composite services and the average response time. This paper also designed a resource-division concurrency control algorithm for composite web services, which take full account of the composite service affairs of the various concurrent circumstances, introduce resource units, coarse-grained and fine-grained division concepts to ensure the transaction concurrency efficiency. This algorithm is verified by testing the transaction concurrency control semantic serializability. Finally according to the CICS transaction manager lack of composite web services transaction support, designed a prototype system includes a transaction manager, concurrency control module, error recovery module.In this paper, focus on the research of composite service transaction model, error recovery, concurrency control and prototype system for the composite web services, providing the new ideas and methods for this research area.