Flex 2: Software Development Kit for Rich Internet Applications Aimed for Flash Player

Flex 2 is a Rich Internet Application framework for building responsive Graphical User Interface (GUI) applications deployed on the Adobe Flash player plugin which is available in all modern A-grade browsers. Flex 2 applications are written using a markup language, MXML, and a JavaScript-like programming language, ActionScript 3. A Flex application's MXML and ActionScript files are compiled down into SWF bytecode and run on the Flash 9 player.

Traditionally the Flash player has been used for streaming videos or playing vector-based games. The YouTube video player for example is developed in Flash. The Flex 2 framework is an abstraction layer and set of MXML and ActionScript libraries for building cross platform User Interface applications. Flex 2 applications, like Flash, run on the client-side, or browser and can communicate with a Ruby on Rails, PHP, or Java based server-side application.

Up to now the tools of the trade for building any sort of web application involved creating a set of HTML, CSS, and JavaScript files for producing the client view. HTML was used to layout out form elements such as text fields, CSS was used to customize the theme or look of the web page, and JavaScript was used to handle user validation and other user events. Writing the front end of a web application using recommended standards such as HTML, CSS, and JavaScript has been a pain for developers because the request-response nature of HTTP, browser incompatibilities with said standards, and lack of a rich UI components like tables in HTML.

The issue about the request-response nature of HTTP, where each server request requires a new page reload is solved with Asynchronous JavaScript and XML (AJAX). AJAS solves the issue with the request-response nature of HTTP by dynamically and asynchronously loading additional fragments of HTML from the server making the browsing experience feel more responsive and rich. Browser incompatibilities and lack of rich UI components has been address with JavaScript libraries such as the Yahoo! User Interface (YUI) library. AJAX and YUI provide a good start for modern web application development but they still don't protect the developer fully from browser incompatibility and still lack rich and responsive UI components.

I like to think of Flex 2 as Ajax 2.0. Flex 2 is a complete, consistent, and standards based application framework for developing responsive, usable, and great looking web applications. Since Flex 2 is built on top of Flash, Flex 2 has immediate support for Rich Media such as audio and video formats. Also, the Adobe Flash player is thought to be deployed in 98.7% of the Internet enabled desktops in the world, a ten percent lead over Java the second most pervasive software. Adobe is not only pushing the Flex 2 Software Development Kit for building cross-browser web applications but also developing cross-platform desktop applications with the Apollo runtime.

Flex 2 is being pushed hard by Adobe and I foresee a large developer adoption in the next year. As explained here, Flex 2 is a viable, and I would say, better option for developing Rich Internet Applications than with the tried and busted HTML, CSS, and JavaScript combination.