Interface Automata Based Verification Of Web Service Composition

Nowadays, with the constant development of Web services technology, service-oriented computing has become a research hotspot of software engineering. By reusing the existing services to combine the service, it can make the enterprises to build flexible and loose-coupled distributed systems more efficiently and effectively. How to make use of the existing service to build an business system which is more complicated and more powerful and to verify the consistency of service combination and business requirment is our key research currently.To solve the problem that there is no such a model which can support graphical display and formalized variation of the service composition, this paper presents a service composition model based on the interface automata to extend the automata. Meanwhile, the model describes service operation and service semantics. The paper designs a transformation algorithm from BPEL process to interface automata model. The model uses composition of interface automata to execute the composition of service. By the way of testing the behavior model of interface automata to verify the consistency of service and business requirements. Experiments have approved that service combination model based on interface automata can express BPEL procedure accurately and completely. It can verify the consistency of service procedure and business procedure.To the question of lack of verified method based on Qos needs, this article presents a model building method to verify the QoS requirements on the basis of interface automata. Except quantitative describing the service quality attribute, the method also designs a formalized expression aiming at Qos requirements. To avoid the shortcoming of BPEL's inefficient support to QoS attributes, it designs a label to describe QoS attributes in BPEL. This method will do QoS needs verification for each operation service after the combination of the interface automata model, comparing with other QoS verification methods. It can verify Qos requirements efficiently.This paper focuses on the research of the services composition and services verification, including service composition model of interface automata, the consistency verification between service composition and business function and the verification of QoS requirements. These are effective attempt research and provide new ideas and methods for the further research on the technology of Web services composition and verification.