Research Of Workflow Engine Based On Colored Petri Nets

Workflow engine provides the server for the workflow execution environment. As the core, the most complex component parts of the workflow management system, before the system development, we need one favourable model to accurately describe the internal scheduling mechanism and analysis process unit of workflow engine. UML is used for the modeling of the traditional workflow engine, according to the engineering methods of building and preserving an effective, practical and high-quality workflow engine. However, this method has no ability to simulate the dynamically behavior of workflow engine at runtime, but just can analyze the statically design on the system. Therefore, this method does not have enough appropriate tools to analyze the model quantitatively. For now, there is no research to learn the workflow instance scheduling by the workflow engine modeling in the workflow management system development.This paper takes up with studying a method of workflow engine based on the colored Petri nets. The workflow engine model based on the colored Petri nets can not only describe the structure and mechanism, but also can simulate the engine behavior, ensure the correctness by the simulation and properties analysis of the engine design. Firstly, a workflow engine model based on the colored Petri nets is established to describe the structure of workflow engine clearly. The colored tokens are used to express the objects information, such as process definition, instance and so on. The changes of the place status express the workflow instance scheduling mechanism. Secondly, through the loading of workflow definition model, the simulation of the engine behavior is made on the workflow engine model. It can ensure the logic correctness of workflow engine model. Thirdly, through the state space of the engine, we can examine the safeness, liveness and fairness properties of the engine model, this method can ensure the engine model correctness. Finally, according to this workflow engine model based on the colored Petri nets, the workflow engine based on XML is now accomplished and successfully used in a workflow management system. The engine follows the XPDL standard, which is presented by the Workflow Management Coalition. Achieve the workflow running by the communication with some integral parts, such as the management platform, the client, the workflow definition tools and the workflow system applications.This paper has the research of workflow engine based on colored Petri nets in order to analyze the workflow scheduling algorithm. Before the system development, we have to simulate the engine behavior, analyze the workflow engine dynamic properties, according to the simulation result and state space report, we improve the workflow engine design. With the perfect design of the workflow engine model, it can not only reduce the costs and risks of engine development, but also improve the quality of the engine and efficiency of development. In addition, the analysis method is also applied for the other complex software system development.