| Along with the development of the Internet and the electronic commerce, modern business becomes more and more complex. Problems such as business reorganization and cross-platform have brought challenges and opportunities for the development of workflow management system. At present time, the process definition of most WfMS is static, but the real world is complex and dynamic, there are some definitions of the business process can't be given in advance. They can only be improved according to the relative data in the process of specific cases. Because of the alteration or the reorganization of business, people may modify process dynamically at execution time. How to make WfMS meet the needs of changes with good flexibility, interoperability and extensibility, has become a focus of workflow.BEA and IBM have jointly issued the white paper in March 2004. This white paper proposes a combination of BPEL with Java, named BPELJ, that allows these two programming languages to be used together to build complete business process applications. It integrates BPEL's good interactive ability of Web Services with Java language to improve the weak point of BPEL. By enabling BPEL and Java to work together, BPELJ allows each language to do what it does best. It can provide better support to Web Service and SOA.After the deep research and study of the present workflow technologies, a dynamic workflow management system based on BPELJ is presented in order to solve the problems of flexibility, interoperability and cross platform ability.The major job of this thesis is as following:1. In order to solve the problem of workflow management system's flexibility, a workflow model which supports dynamic business process is proposed. In the model, some process definitions which can not be defined in advance or may be changed in the course of implementation are put off until run-time.2. Agent technology and web service technology are adopted in the system. We extend the traditional workflow structures, and design two new agents: Process-extending Agent and Web Service Agent. Process-extending Agent is responsible for process extending and dynamic routing at execution time. Web Service Agent is in charge of finding and calling business processes which are packaged into web service in order to support distributed system. They overtake part of workflow engine's function together, which makes the system have better flexibility and adaptability. This provides favorable support to distributed system.3. At the phases of process definition and system execution, the thesis provides a method of hierarchies in order to promote the system's ability to describe and manage to complex business.4. To avoid defining a process repetitively, a public process library is added in the data layer. It is used to store those business processes having common characteristics, which simplifies the process of defining complex business. Therefore, the reusability of the process is promoted.5. A dynamic workflow management system based on BPELJ is designed。The structure and working principle of the system are discussed in detail with its design and implementation. The excellent flexibility, interoperability and adaptivity of the system are illustrated by a practical project---the system for the management and calculation of invoice in gas station. |
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