Based On The Workflow Execution In The Distributed Environment Of The Message System Key Technology Research

Workflow is a collection of units of work called workflow tasks which cooperatively realize a business objective by utilizing system resources such as database, aiming at the wholly or partly automation of enterprise business process. Now, most of workflow management systems are based on standard client-server architecture and the whole system is usually executed in a central server that usually represents a single point of failure, which compromises the availability of the system. Also, these systems have an intrinsic scalability limitation. In this thesis, we propose a fully distributed architecture for the workflow management system, focusing on workflow distributed execution mechanism. It is based on the idea of harmony theory by MichaelS. Malone, a professor of MIT. Such an architecture would fit naturally to the distributed heterogeneous environments. Further advantages of distributed enactment service are failure resiliency and increased performance since a centralized scheduler is a potential bottleneck.In the thesis a distributed workflow enactment service is described. Main contributions of the thesis are as follows:1. Firstly, we discuss the new characters of current enterprises in the environment of global economy. Now, enterprise business presents distributed, collaborative trend with more and more mergers occur everyday. In this thesis, we study and analyze such characters in detail.2. Secondly, a hiberarchy business process model is established, using the harmony theory by professor Malone. In this model, an enterprise is divided into several business domains according to the relationship between business branches. And here, three kinds of business process type are defined: global business process, collaborative business process, private business process. Such a process model fits naturally to the organization structure of enterprises.3. Last, we study the mechanism of tasks scheduler and allocation in distributed environment when a workflow is executed and present a three-tiers architecture, running in a Weblogic server. The whole execution system is comprised of several workflow engines, which communicate with each other, using persistent messages.The prototype of distributed workflow execution environment is realized at the end of this thesis, and some conclusions and future works are proposed.