SAGE Display Controller


SAGE Display Controller is a multi-tier web application developed using Google Web Toolkit (GWT), JAVA Servlets and several third-party libraries available for GWT. Google Web Toolkit (GWT) is an open source Java software development framework to develop AJAX (Asynchronous JavaScript) applications like Google Maps and Gmail.

The architecture is comprised of three modules namely :

JavaScript client module

The JavaScript client module is resposible for all the UI components of the application. The GWT library translates all the UI widgets to their corresponding HTML, DHTML elements and also generates the neccessary JavaScript code to manipulate the DOM (Document Object Model). Using the AJAX functionality, the client makes asynchronous calls to the server to obtain updated information from the server based on user's interaction with the environment. The AJAX feature lets the UI widgets update themselves with new information without requiring to reload the pages, thus giving a feel of dekstop applications.

JAVA Servlet module

The servlet module handles all the requests sent by the client server and acts as a proxy between the native SAGE application and the clients. The communication between the server and the native SAGE application is done using the python based SAGE proxy server module. Using a servlet, helps avoid the same server JavaScript security violation which doesnot allow the browser to send requests to any other server/domain from where they were hosted originally.

SAGE proxy server module