Research On Web Service Composition Based On The Service Net

With the development of information technology,The Web service technology becomes the core technology of service-oriented computing.A distributed computing model of Web service composition becomes an effective mechanism of service integration on the network.Web services composition technology is mainly study the Web service formal expression,the Web service composition formalization method and the Web service composition verification and so on.Based on the previous research on Web service composition technology,the following three aspects are studied.(1)Based on the Logical Petri Net,The Service Net is extended for modeling Web service composition,and the Web service composition structure(order,branch,parallel,etc.)is formally described.In order to analyze the rationality of Web service composition structure based on the Service net,the rationality evaluation standard of Web service composition structure based on the Service net is given.Using the reachable tree of the Service Net to verify the rationality of the model.Applying the Service Net to model Web service composition of e-commerce sales system,according to the rationality verification standard of the service composition structure,using reachable tree to verify the rationality of the Web service composition structure of e-commerce marketing system.(2)For the service execution with time constraints of Web service composition,we propose the Time Service Net which extends transition with time constraints based on the Service Net.The time constraint of transition in the Time Service Net corresponds to the time constraint of Web service executable.The rationality criterion of Web service composition structure with time constraint includes service schedulability.The paper gives the calculation method of the service schedulability,and also gives the timeliness calculation method of the whole service composition.The Time Service Net is applied to model Web service composition of the insurance compensation system,and the schedulability of the Web service and the overall timeliness of the insurance compensation system are analyzed.(3)Composite service net is proposed to formally describe the Web service composition which is inter-organizational and has no strict time constraints on service execution.Due to the huge structure of the model of inter-organizational Web service composition,it is difficult to adopt the reachable tree analysis model's structure rationality.This paper proposes a static network structure method to analyze the rationality of inter-organizational Web service composition structure.The Composite Service Net is applied to model of the inter-organization Web service composition of the electronic commerce transaction,and the rationality of the e-commerce transaction model is analyzed.