Design And Implementation Of Workflow Engine Based On Grid

Grid is a new technology that has been flourishing quickly in recent years. Its occurrence has whipped up the next wave of Internet technology. Computation grid originally aimed to combine supercomputers through Internet to solve complex and large-scale computing problems. At present, the aim has evolved into combining various types of computers in different areas in a reasonable way and the highly integrated organic unity can supply powerful computing abilities to common users. Supporting mechanism of using various resources as a new platform of network computing, a virtual computing system could be made up of heterogeneous, dynamic, distributed resources with grid. The open source Globus Toolkit is a fundamental enabling technology for the Grid, letting people shares computing power, databases, and other tools securely online across corporate, institutional, and geographic boundaries without sacrificing local autonomy. It becomes the practical standard tools of the grid.This article studies the architecture and functions of GT 4. According to a sample of a grid service, it analyzes the invoking procedure of the services, acquirement of the resources and the mechanism of the stateful services detailedly, does the research on the design patterns of the services which should be carefully chosen for the needs of scalability and maintainability in a real world, discusses the security of the services validated by capturing the transmission data between the two services communicated with each other.According to the practical need and the grid services technology, the article discusses a workflow engine based on the grid which successfully deployed into a real system, analyzes the working procedure, invoking mode, components of the engine and the method of extending. The engine could manage the flow of the work, the change of the state, the process of the flow data and the delegation of the business activities. To extend their needs, the clients just need to do a few developments based on the API supported by the engine. It reduces the workload and enhances the flexibility of the system, from which the robustness and the extendibility of the system will be benefited. Meanwhile, the affect of the re-development and maintenance decreases for the alteration of the system, and it is an essential archetectural supports for the refactoring and upgrading. It is the embodiment of the service oriented, the abstract of a higher logical layer and the futher separation of concerns that makes use of the engine for the centralized control and management.