The Research And Implementation Of Transaction Processing Mechanism In Bcsep

The emergence of Web service has brought great opportunities to enterprise applications. After recent years of development, Web service and its composition technology has been gradually improving and standardizing, and has been used by many business organizations. The research group which the author participates in proposed a model of business service and a business service based composite service execution platform (BCSEP), and provided a platform on which enterprise applications could be rapidly established based on Web services while encapsulating Web service in business domain level.In Web service composition, it is often required to handle interaction and composition processes between Web services. In this kind of processes, the reliability and consistency of execution result of Web services must be guaranteed, and all kinds of runtime exception must be solved in time. This requires Web service composition systems to provide support of transaction processing mechanism. This thesis takes the transaction processing mechanism in BCSEP as the main research problem.Transaction processing in Web service composition system is different from that in traditional database system.In loosely coupled environment of Web services, the correctness of transaction can not be completely restricted to the standard of traditional ACID properties. Transaction of long running Web service composition needs loose transaction ACID properties.The loose atomicity and consistency of global transaction can be met by compensating transaction.For the specific needs of BCSEP, this thesis proposes a transaction processing mechanism based on compensation which means roll service execution results back through compensation. In BCSEP, transaction processing function is realized by setting transaction coordinator in the event processor. Transaction coordinator is primarily responsible for the initialization, coordination and management of transaction processes in the platform. While the system is running, the transaction coordinator coordinates and manages the transaction processes by continuingly interacting with the business process handling module in the event processor.This thesis designs and realizes the event processor which supports the transaction processing mechanism in BCSEP. The platform transfers transaction processing information by setting transaction coordination messages in service messages; and manages the-execution status of services by maintaining a transaction participant services table in the transaction coordinator. The platform sets transaction flag in the mapping relationship between services in order to define transactions in business processes, and assures the execution of the business processes and transaction processes in the platform by generating rule expressions of mapping relationship between services and sharing data caching mechanism.