The Study Of Multi-Engine Workflow System Control Architecture And Data Consistency

The research of the workflow originates the 70's of 20 centuries. By the limit of network technology most workflow systems are used for document management in enterprise internal network at the beginning of the development. When it comes to 90's of 20 centuries, along with technical development applying of network technology, the electronic business is promoted greatly. Then it becomes likely to cooperate business between departments of one company, between companies and companies or between companies and subsidiary companies. There are many opportunity and challenge for the development of workflow system.Working with the workflow system. The biggest advantage is that it separates the application logic and the execute logic. Then changing the workflow process model, not changing the program code, can change executive process. It also can be binded some management process in one task. As a result, company can organize workers, information and applications effectively. The workflow technology can support company to control the management and production organization, to make wise decision. In other words, it realizes the goal of "send the appropriate information to the appropriate man within appropriate event at the appropriate moment".Currently, as a means of supporting the BPR and BPA, research and application of workflow technology is increasingly valued with business field and academic circles. With the development of computer network technology and distributed database technology, growing up of multi-computer cooperation technology, the distributed workflow system becomes first choice to resolve enterprise business.This article is based on my cooperation in the research team of workflow technology. Our team develop a kind of distributed workflow system: J2EE－Based Distributed Multi-Engine Workflow System(DMEWf). We realize its architecture and functions with java language. As a member of the research team, I'm with responsibility for the control engine and whole control architecture.Being a distributed workflow system, the distribute characteristic of DMEWf represent in these aspect: (1) the distributed design of the system control architecture. The DMEWf is designed according to the reference workflow model of the WfMC. It is separated with workflow process define tools, organization management, resource management, workflow engine, process instance management and parts. Each part is designed separately in function, called by interoperation each other. All the parts work as one distributed system. (2) the distributed execution of engine. There are two type engine: one control engine and some domain engines. Each domain engine is distributed in different application server, to make process instances and activity instances running in different location. The only one control engine is in charge of loading and controlling all the domain engines. The workflow client send request to control engine. Then the control engine distributes the request to the homologous domain engine, gets the result and sends back to the workflow client. The administrators can control and watch all the domain engines, the process instance's status through the control engine. In other words, the workflow enactment services are consists of several parts to run process instances inside, but is one whole interface outside. All the requests outside are distributed to domain engines by control engine. The workflow client doesn't need to know the detail of the Workflow enactment services, and the domain engines doesn't need to interchange with workflow client directly. All these issue make up distributed system. The control engine carries the workflow client, the domain engines, the workflow process model tools, and the instance database closely. (3) the distributed storage of the workflow process model. The workflow process models and instance data of DMEWf are stored in one central database server. But each domain engine keeps a copy of workflow process models. When it initiates, the domain engine get the copy from the central dat...