Simplifying Web Service Discovery & Validating Service Composition

Web services are software components developed to simplify machine-to-machine interaction over the Web. Many researches are targeted towards Web service standardization, and these efforts have significantly contributed towards improving functionality of Service Oriented Architecture (SOA). However, there are number of issues yet to be resolved. Among them, one of the major challenges is the standardization of Web service composition. When a single web service cannot satisfy the given request, composition of web services need to be incorporated. In this paper, we address Web service composition problem with the signature-based service discovery and composition approach. In the proposed approach, each web service is described by WSDL. Our design eliminates the need of complicated discovery agents like UDDI and also facilitates validation of the service before actually accessing it for integration. The composition problem has been modelled as a finite state machine, which means if the all the intermediate states are rightly composed then the final composition is successful. We propose a simple yet efficient algorithm DISCOMP for the discovery and composition. This paper analyses build time and runtime issues related to signature-based approach. We support our design decision with implementation and performance results obtained on a decentralized setup.