Constructing XML-speaking wrappers for WEB applications: towards an interoperating WEB

We discuss an architecture for integrating WWW applications that offer information and services in the same domain. At the center of this architecture exists a mediator, whose responsibilities are to interact with the user and to effectively exchange information with the underlying applications in order to accomplish the user's task. The integration and interoperation of the existing applications are based on the availability of a common domain model, explicitly represented in XML. More specifically we have developed a general method for constructing wrappers for Web-based applications, so that they exchange data with shared semantics such as defined in the XML domain model. At run-time, the user's requests result in the mediator's XML queries to the application wrappers, which, in turn, invoke appropriate methods on the wrapped applications and extract XML data from their responses to these queries.