PEWS: A New Language for Building Web Service Interfaces

Recent proposals in the domain of interface description languages for web services stress the importance of specifying the dynamic, behavioral aspects of the services. The goal of this paper is to introduce a new interface description language, called PEWS, that uses predicate path expressions to define web service behaviours. Our proposal represents a simple but expressive way to describe order and conditional constraints over web service operations. PEWS aims to be used not only to the specification of simple web services but also to be a tool for describing service composition. In this paper, we use the Action Semantics framework to present the syntax and semantics of the most significant parts of PEWS and we introduce XPEWS, the XML-based version of PEWS used to publish service behaviours for future searches and composition. The definition of XPEWS is done by giving the XML Schema that defines the syntax of XPEWS programs.