Implementing a State-Based Application Using Web Objects in XML

Abstract

In this paper we introduce Web Objects in XML (WOX) as a web protocol for distributed objects, which uses HTTP as its transport protocol and XML as its format representation. It allows remote method invocations on web objects, and remote procedure calls on exposed web services. WOX uses URIs to represent object references, inspired by the principles of the representational state transfer (REST) architectural style. Using URIs in this way allows parameters to be passed, and values returned, either by value or by reference. We present a case study, in which an existing chart application is exposed over the Internet using three different technologies: RMI, SOAP, and WOX. WOX proves to be the simplest way to implement this application, requiring less program code to be written or modified than RMI or SOAP. Furthermore, as a consequence of its REST foundations, WOX is particularly transparent, since any objects that persist after a WOX call may be inspected with any XML-aware web browser. It is also possible to invoke methods of persistent objects through a web browser.