An Adaptive Framework Of Dynamic Web Service Composition Based On Dynamic Workflow

With the popularization of the Internet, a larger number of reliable Web services surged on the Internet. But as the demands of people's working and living enhanced continually, a single Web services can not meet the various needs of people because of its limited function. So it is necessary to find new ways, using network resources efficiently, to solve the contradiction between the single Web service and the complex business needs. Web services need to be combined together to provide more powerful functions which are very important to deal with today's complex business logic.Existing Web services techniques are generally combined through static hard-coded. In the design stage of the Web service combination, the Web services which participate in service combination are designated by designers. This approach is suitable for the long-term unchanged business requirements or fixed business flow. As demands of modern business are changed constantly, once the business needs changes the business flow need change too. Because of the lack of flexibility, static Web service combinations isn't adapt to the new demand. If redesign services composition according to the business again it will increase the cost of enterprise or the burden of designer inevitably.According to the changeable situation of business needs in modern enterprises, an adaptive framework of dynamic web service composition based on dynamic workflow is proposed. By using the dynamic characteristics of dynamic workflow model modification, the WS-BPEL is used to combine services dynamically. Business flow model can build according to the user's business need in the framework, and combine the single service together dynamically to meet user requirements. Meanwhile, the requirement of users for QoS can be satisfied in the framework. In order to enhance the ability of the framework to deal with failures of combinations, this paper also adopted the method of resolving the abnormal events that workflow encountered, to make service composition system have adaptive characteristics. Finally, a prototype system shows that the framework can deal the dynamic and changeable situation of complex business requirements and combine the Web services flexibly and efficiently.