A Formal Transaction Model for Reliable Web Service Composition
A key challenge of Web service composition is how to ensure reliable execution. Due to the inherent autonomy and heterogeneity of Web services, it is difficult to predict the behavior of the overall composite service. The lack of techniques that support n
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A Formal Transaction Model for Reliable Web Service Composition Weitao Ha
Abstract A key challenge of Web service composition is how to ensure reliable execution. Due to the inherent autonomy and heterogeneity of Web services, it is difficult to predict the behavior of the overall composite service. The lack of techniques that support nonfunctional features, such as execution reliability, is widely recognized as a barrier preventing widespread adoption. In this paper, we propose a formal transaction model, and modeling method is based on first-order logic. The model uses acceptable state of user as judgment criterion for accuracy, and the validity of the model is proved.
Keywords Web service The acceptable state for user Transaction Well-form
25.1 Introduction Web services approach is extending the Web from an information support to a B2B middleware. One of the main concepts that offer this technology is the ability to define a new composite service using existing services. In this paper, we are interested in how to ensure reliable Web services compositions. By reliable composition, we mean a composition where all its executions are correct (from a business point of view) [1]. An execution is correct if it reaches its objective or fails according to the designers’ requirements. Due to the inherent autonomy and heterogeneity of Web service, it is difficult to predict the overall behavior of a
W. Ha (&) College of Mathematics and Information Science, Network Engineering Technology Center, Weinan Normal University, Weinan, China e-mail: [email protected]
Z. Zhong (ed.), Proceedings of the International Conference on Information Engineering and Applications (IEA) 2012, Lecture Notes in Electrical Engineering 218, DOI: 10.1007/978-1-4471-4847-0_25, Ó Springer-Verlag London 2013
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composite service. For the long transaction of WSC, strict atomic demands will cause tremendous waste of time and resources. Moreover, traditional locking mechanism may lead to long-term occupation for resources and reducing performance [2]. As stated previously, the traditional transaction processing technology cannot be used in transactions of WSC, and a new transaction model for WSC should be proposed.
25.2 Transaction Model for WSC Web services have autonomy, heterogeneous and dynamic characteristics in a loosely coupled environment, which is different from traditional transactions [3]. The concept of transaction type and transaction state of Web service should be introduced, and transaction mode which can reflect the actual situation and characteristics of business process can be established. The formal description of model is given. Definition 1 (Transaction model for WSC) Transaction model for WSC is represented by a quadruple TMWS = (WS, CF, TF, DF). WS is a finite set of Web services. CF is Control flow, which represents the structural relationship between Web services. TF is set of transaction relationship, which represents dependencies of transaction between Web services. DF defines the flow of information
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