The Research And Implementation Of Workflow Engine Based On Web Services

Due to the ability of handling complex transactions in heterogeneous environment, workflow has gained more and more attentions in the area of scientific research, e-government and e-business in recent years. With the rapid development of Internet applications, collaborative working is becoming a typical application mode. Traditional workflow technologies cannot well adapt to the distributed applications in multiple departments and multiple organizations, which will have complexity of implementation and hight cost. Web services provide an approach to resolving this problem. Web service is the single entity that can be encapsulated. It can also be published on the Internet as a function set. Its characteristics of dynamic and interoperability can resolve the problems in the traditional workflow systems. Therefore, bringing web service technolgies into workflow management systems will have positive effects to the research and application of the workflow technologies.Web service technologies have been used to implement workflow management systems under heterogenous and distributed enviroments in this dissertation. So the cost of system development can be reduced and the features of dynamic and interoperability can be reached. The main works done in this dissertation are as follows: The components, reference model and architecture of workflow management system are studied. And the function characteristics of each component and relationship between components are discussed.Web service technologies have been studied. The architecture of web service, three fundamental roles and three basic operations between roles are analyzed. The protocol stacks of web service, some standards including SOAP, WSDL, UDDI and WSFL are discussed. How to utiliaze web service technologies into workflow management systems is studyed, which can solve the problems in integration and dynamic coupling between different platforms. The implemention can be realized easily, and the cost can be cut down.Referencing the WFMC reference model, a web service- based architecture of workflow management system is proposed in this dissertation. Towards the studied problems, the system model and the execution status of workflow are simplfied and extended. A workflow engine which is a core component of workflow system is designed. The function features and interfaces of the engine module are discussed. A prototype of the system is implemented.