Design And Implementation Of Lightweight Workflow Engine

As an essential technology to realize business process automation, Workflow technology becomes a research hot spot gradually these years. Most of existing workflow products are huge,complex,hard to use, and they are often unique in their style and can't integrate with business applications seamless. These cause they are not fit for many medium and small native projects.PNFlow, a lightweight Workflow Engine based on Petri Net,is constructed aiming to solve these problems. PNFlow has a clear and open architecture, a simple but mature model, and it is lightweight and transplantable. This thesis discusses the PNFlow from three aspect :WfMS architecture, workflow model and WfMS development framework. The architecture of PNFlow fully conforms to the standard of workflow reference model of WFMC (Workflow Management Coalition),so that it can communicate with other workflow engines.The PNFlow's workflow model adopts Petri Net to modeling system, effectively and practically. PNFlow uses Struts+Hibernate, a modern and popular J2EE develop framework to fulfill its design goal effectively.This thesis elaborates the design and implementation of PNFlow engine. Fully adopting the object-oriented design ideas, the workflow engine is composed of logic classes and entity classes. Logic classes are the object model of main entities of the workflow model, the execution of workflow is the response of the interaction of objects of logic classes. Entity classes provide infrastructural DB service for logic classes. The part of implementation introduces core scheduling mechanism, the scheduling algorithm of which uses the sutra algorithm of Petri Net. Finally I designed and implemented the system of shopping online and described how the engine is used in which.