Technology Overview

Technology Overview of the OUAF System

Information is presented in a Web browser using HTML and JavaScript (not Java, e.g., no applets). The browser communicates with a Web Application Server via HTTP.

The Web Application Server is divided into several logical tiers: presentation services, business logic, and data access. Inbound HTTP requests are handled by Java Servlets in the presentation layer, which may in turn invoke data service objects. In turns, these objects may route control to Java-based business entities, which use the Hibernate ORM framework for data access and persistence.

Various static data (control tables for drop-downs, language-specific messages/labels, etc.) are cached in the presentation layer of the Web Application Server. The presentation layer makes use of XSLT technology to create HTML for the browser.

As the browser may need several "pages" to show all the information relating to a particular business entity, a JavaScript "model" is used to manage the data in toto, and the Internet Explorer XMLHTTP object is used to send the data to the server as an XML document. Data is provided to the browser as literal JavaScript. The specialized portal and dashboard areas use server-side XSLT technology to render the final HTML directly on the server. The HTML for grids in the browser is created using client-side MSXML XSLT transforms.

This kind of architecture is described as Asynchronous Javascript and XML (AJAX).