Research And Implementation Of Exception Handling In Workflow Engine

With the development of social production, the cooperation of enterprise internal and external shows the increasing trend of process. At the same time over-reliance on human of business processes begin to show its shortcomings, but the emergence of workflow system just changes this current situation. In the building of enterprise IT, workflow system is more and more widely used to build the real process-oriented business services and applications. Also as the emergence of electronic commerce, enterprise business processed become more complex, the situation that a complete production process becomes regional and cross-enterprise is very normal, although we use workflow system. In the complex process the integration of enterprise information systems generate exception inevitably, and the exception brings negative impact on enterprise production, the handle of exception is the current urgent need of more and more enterprises. In general, for a perfect and reliability workflow system, the demand is not only ensure the normal execution of business process which does not have exception but also ensure the execution of business process which has generated exception. Therefore, the research and implementation of workflow engine exception handling is the main discussion in this paper.We first introduce the workflow engine, XPDL process definition language and some other basic techniques. With the research of the process exception's classification, the process exceptions are divided into expected exceptions and unexpected exceptions, and we will give correspond design and implementation of the handling of these exceptions. For expected exceptions, we will adopt the high scalability of XPDL to handle them. The handling procedure includes the modeling of exception class and publish of interface that user defines by themselves. Advantage of this handling not only reduce the difficulty of the user handling but also improves the efficiency of development of exception handling class. For unexpected exceptions, we present a process-based replacement policy handling from the starting point of automation and real-time, the human intervention is also included into this policy. For the replacement policy, we put forward conception of "Process Definition Instead Library" and specific selection method. For the human intervention, it is just the handling policy when there is no replace process in the predefined "process definition Instead Library". In conclusion, we present the system architecture and functional design of those handling policy, and complete the development finally, and we prove the feasibility of the implementation through case in point.Finally, we give the summary and work on our next prospect of this paper in summary and Outlook section.