The Research And Implementation Of Exception Handling Mechanism In Business Service Based Composite Service Execution Platform(bcsep)

Service composition provides more powerful business functions through dynamically composing available Web services together, which brings infinite opportunity for enterprise business integration. Our research team proposes a business service model to wrap Web services according to features of business domains. Based on the business service model, the researching group of us designs and implements the Business service based Composite Service Execution Platform (BCSEP).Currently, research of business process based Web service composition mainly focuses on description and verification of service composition, and lacks of exception handling of service composition execution. The accomplishment of the composite service execution depends on not only the internal design and state, but also the execution of external participating services. Autonomy of Web service brings great obstacles to external visibility and management, which weakens the capability of Web service exception handling. In light of this situation, this thesis focuses on the mechanism of exception handling in BCSEP and the implementation of exception handling module.This thesis analyses the causes of composite service exception, and classifies the exceptions in BCSEP. Because pre-bound services may fail to satisfy the consumer's requirements due to self-evolution, this thesis proposes the service availability based exception detection mechanism.This thesis uses constraint rules based exception detection mechanism to detect the exception in the platform. When the exception is detected, work-flow execution state is intervened, and the exception information is encapsulated and delivered to exception handling component by the message transmission mechanism.The exception handling module adopts a context-sensitive ECA rules based approach to handling composite service exception (ANALEPTIC). In order to perform appropriate exception handling actions, this thesis sufficiently considers the exception information and the executing states information of the related actions in exceptions occurring, extends Condition part of the ECA Rules to the two parts of exception contexts and process contexts, and defines the data structure and matching algorithm of the exception handling rules. The exception handling Action of the ECA rules is implemented by the exception handling services. The exception handling services are exception handling units of the exception handling policies in BCSEP. By composing basic exception handling services, new exception handling services with complex exception handling policies will be generated.At last, based on researches on exception handling mechanism, this thesis implements the prototype of the exception handling module of BCSEP, including functions of exception detecting, exception analyzing, exception handling. The implementation shows that the exception handling module is effective.