Stateful Web Services -- Auto Modeling and Composition

The web service community has introduced many techniques to cope with the inability of WSDL to describe a service´s behavior. Those techniques range from embedding more XML tags in WSDL, to generate formal behavioral models on top of WSDL. Apart from the efficiency of these techniques, a common problem is that they require manual efforts to model the behavior of a service, and often need informal documentation from service vendors to do so. In this paper, we propose a solution for the above problem by automatically extracting a service´s behavior, directly from its WSDL document. Our approach is based on the utilization of particular WSDL elements, which are usually ignored by bottom-up approaches while generating a WSDL file. We illustrate our process in steps by taking a scenario from Amazon E-commerce Web Service. We also survey the issues with extracting the behavioral models, from the WSDLs of existing web services. Finally, we tested our automatically generated models by composing them together using our service composition framework.