Research Of Correctness Of Web Service Composition Under Environment Constraint Based On Open Petri Net

In practical application, the correctness of composite Web service is not only constrained by other Web services, but also constrained by the Web environment. Because the Web environment has special features, it is difficult to model and analyze by traditional methods and the research on the correctness of composite Web service under environment constraint demand new modeling tools and analysis methods.Firstly, the paper proposes the modeling methods of Web services and Web environments based on open Petri net. Then, in order to analyze the correctness of the composite Web service under the environment constraint, several determining algorithms about correctness of composite Web service are presented. Through interface places, Web environment communicates with Web service, thus an interrelated whole is formed structurally and behaviorally. Because of the communication, Web environment inevitably constrains Web service behavior which is reflected by the correctness of composition. Whether Web environment and Web services can compose is the premise that Web environment constrains Web services, so we should give the condition they can compose. Correctness analysis of composite Web service under environment constraint mainly has two styles:1) if a single Web environment and a single Web service satisfy soundness, correctness can be determined by the soundness of composition.2) if a single Web environment and a single Web service do not satisfy soundness or we do not need to consider their soundness, correctness can be determined whether the composition has deadlock. Finally, a concrete example is given out. Theoretical analysis and experimental results indicate that the methods can analyze the correctness of constraint composite service effectively.