Web Service Partnership Model Research

In recent years, software developing technology has achieved great progress and the concept is heading towards the "software as a service" direction, which has promoted the widely use of web services. There are many new web services generated in the network everyday. Not only the work maybe huge, but it’s also hard to make adjustment when the user’s need changes occasionally, if we combine these web services manually. Thus dynamic web services composition is becoming a new research hotspot, due to its flexibility and fast information integration speed. However, dynamic web services composition is a both complex and error-prone process. In order to find the mistakes and correct them timely before the execution of composite services, it’s very necessary do the validation in the last stage of composition.Some description and verification methods have been put forward to complete the validation task of composite services, but none of them is convenient to utilize. Either they lack visualized representation, or the implementation complexity is high. This paper has analyzed the problem from a bran-new perspective, by introducing the information of web service collaboration history.Firstly, this paper has proposed a way to represent the cooperative relations between two web services, and acquire, store and update it. The successful extent degree of the collaboration is used to quantify the strength of a partnership, which takes the impact of the responsive service’s quality on the partnership as the main basis for its calculation. The service collaboration records can be gathered by monitoring the service log of the server machine where the web service is deployed on, and stored according to its category which is decided by the category of the responsive service. Because of the classification storage structure in the database, the query speed of collaboration record is accelerated. And during the update of collaboration record, a ratio adjusting factor and a time weakening factor are added to the computing formula to ensure the effectiveness of all records.Besides, a cooperative relation model of web services is established, which bases on the existing web services architecture. The model is able to fulfill the function of composite services verification, and for those collaborations that may fail in execution, the model can also provide substituting service recommendations to users. It verifies a composite service according to the successful extent degree of each collaboration, and displays the verification result with a cooperative relation graph, from which users can get the weak point of the composition directly. At the same time, by adopting the AHP method, user’s personal preference on service quality is considered in the sort of candidate services. So the selected services could satisfy the user’s requirements much better. The simulation result has shown that this model improves the successful execution probability of composite services effectively.