WebGuide is a Knowledge Building Environment developed by Gerry Stahl and colleagues at the University of Colorado. It was originally developed as a large java applet. For reasons of efficiency and speed, it was separated into two components: a server (a Java application running with the database on the webserver at the university of Colorado) and a client (a Java applet running on the user's computer in his internet browser). The client and server currently communicate requests and responses (including data to be displayed or stored) by sending a Java object across a TCP/IP socket connection. This means that the client must be a Java program that can create and read transferred Java objects.

We are now converting the client/server connection to one based on XML and using out recursive DTD. Now, the client and server will communicate and pass data by sending a string containing the data coded in XML. The advantage of this is its cross-platform generality. With this connection, the existing WebGuide server can communicate with clients that are not necessarily written in Java. For instance, lightweight clients in Perl can create simple HTML displays that do not require the special computer configurations that WebGuide currently requires.

This means that multiple clients can be developed to provide alternative interfaces to WebGuide. For instance, a Palm Pilot interface could be used to enter quick notes into WebGuide, while a more complex interface provided knowledge management functions. Alternatively, a single user interface (client) could be used to access data in several incompatible systems, assuming they all had servers that used the same protocol based on the XML DTD. Another advantage of the use of XML is to encapsulate changes required when the DTD needs to be changed and the possibility of translating different data schemas into each other through the common DTD. This is handy for rescuing data from older versions of the data schema for the same system.

Go to top of this page

Return to Gerry Stahl's Home Page

Send email to Gerry.Stahl@drexel.edu

This page last modified on August 01, 2003