Research On Service Composition In SOA And Auto-construction Technologies

The service composition achieves the enterprise application integration and the dynamic cooperation, which is beneficial for the enterprise to implement new solutions. It organizes services effectively by a loose coupling way to achieve business process. Along with the expansion of enterprise's applications and requirements of new business, a simple process can't satisfy the complicated and dynamic demands of business anymore. For this large-scale service composition, many problems exist as follows:①The level of the automatic composition is low. The present service composition can partly implement automatic processing, but there is no fully automatic composition in the whole sense. Most of the service composition still needs manual intervention or configuration.②The existing service resources can't satisfy business requirements. All the service compositions are based on certain service resources which compose target processes. In that case, shortage of the essential services definitely affects the construction of target processes.③The elasticity of the service composition is weak. It is essential to split and reconstruct processes in a large-scale to satisfy requirements of the new business. However, it would inevitably influence construction speed by refining process and compositing new service.To solve the above problems, the thesis gives analyses and results of the following items:①Analysis of present service composition methods and their advantages and disadvantages are proposed. And Finite State Automata (FSA) was selected as a theoretical foundation to build the automatic service composition model.②The consistency of FSA's elements and BPEL elements was studied, which was mainly reflected in mapping relations and the transformation process of the formal description and the actual service state.③The virtual service was proposed to make up service resources shortage, which was based on clear relationships of each execution state. Service composition algorithms of the virtual service were also proposed to build business processes. ④A prototype system was designed and implemented, which was based on the FSA theory. A static composition of traditional WSDL + BPEL was replaced by a dynamic composition of automatic WSDL+ BPEL generator, which fulfills the improvement of service composition's elasticity.