GUI framework communication via the WWW Thomas Tilley, School of Information Technology, Griffith University, Australia 4215, T.Tilley@gu.edu.au Peter Eklund, School of Information Technology, Griffith University, Australia 4215, P.Eklund@gu.edu.au Abstract This paper discusses experimental results and design issues arising from a project to implement a distributed, platform-independent GUI framework. Four different approaches for distributed-object communication are presented. Each approach is evaluated according to its execution time and engineering cost. Keywords: World Wide Web, GUI, client/server, Java, CORBA 1 Introduction Two main options exist for the implementation of an Internet front-end for applications with Graphical User Interfaces (GUIs). The first is to "hard-code" a remote interface specifically for the application and distribute it to client computers. The problem with this approach is the inflexibility of the resulting interface. If the application is modified then the GUI software needs to be changed and re-deployed to clients. World Wide Web based deployment options include: FTP or HTTP down-loading of the client software; using "push" technology to update clients; and distribution of the front-end as a Java applet. An alternative approach that minimises the need for client re-distribution is to provide a GUI framework [1, 2]. Using the framework an application’s interface can be built dynamically directly from the application server. If the appropriate set of GUI components are implemented on the client the remote GUI can provide the same "look and feel" as the program running locally on the application server. An additional advantage is that changes to the back-end (server-side) application do not necessitate modification to the front-end (client-side). Any re-arrangement of the application’s user interface (UI) is reflected dynamically by the remote client. 2 Project Overview The aim of the project was to provide a platform independent GUI capable of providing remote access to an application via the Internet while retaining the native "look and feel" of the application. This was achieved using a two-tier client/server approach that has parallels with the X-Windows System and "thin client" Network PC paradigms. The server-side target application was a Spatial Database Management System (SDBMS) providing real-time 3D data visualisation. The SDBMS was implemented in C++ on the Silicon Graphics IRIX platform.