|Initial release||March 2004|
|Stable release||188.8.131.5283 / December 18, 2009|
|Operating system||Windows, Mac OS X and Linux|
|Available in||English and Japanese|
|Type||Rich Internet application|
|License||Mozilla Public License (Flex Builder and Flash Player under commercial license)|
|Website||Adobe Flex Homepage|
Adobe Flex is a software development kit released by Adobe Systems for the development and deployment of cross-platform rich Internet applications based on the Adobe Flash platform. Flex applications can be written using Adobe Flex Builder or by using the freely available Flex compiler from Adobe.
The initial release in March 2004 by Macromedia included a software development kit, an IDE, and a J2EE integration application known as Flex Data Services. Since Adobe acquired Macromedia in 2005, subsequent releases of Flex no longer require a license for Flex Data Services, which has become a separate product rebranded as LiveCycle Data Services. An alternative to Adobe LiveCycle Data Services is BlazeDS, an open-source project that started with code contributed in 2007 by Adobe.
In February 2008, Adobe released the Flex 3 SDK under the open source Mozilla Public License and so Flex applications can be developed using any standard IDE, for example Eclipse. There is also a commercial and proprietary IDE called Adobe Flex Builder.
Traditional application programmers found it challenging to adapt to the animation metaphor upon which the Flash Platform was originally designed. Flex seeks to minimize this problem by providing a workflow and programming model that is familiar to these developers. MXML, an XML-based markup language, offers a way to build and lay out graphic user interfaces. Interactivity is achieved through the use of ActionScript, the core language of Flash Player that is based on the ECMAScript standard.
The Flex SDK comes with a set of user interface components including buttons, list boxes, trees, data grids, several text controls, and various layout containers. Charts and graphs are available as an add-on. Other features like web services, drag and drop, modal dialogs, animation effects, application states, form validation, and other interactions round out the application framework.
Although popular as a rich internet application development environment, Flex is not without its detractors. In February, 2009, analyst firm CMS Watch criticized the use of Flex for enterprise application user interfaces.
Macromedia targeted the enterprise application development market with its initial releases of Flex 1.0 and 1.5. The company offered the technology at a price around US$15000 per CPU. Required for deployment, the Java EE application server compiled MXML and ActionScript on-the-fly into Flash applications (binary SWF files). Each server license included 5 licenses for the Flex Builder IDE.
Adobe significantly changed the licensing model for the Flex product line with the release of Flex 2. The core Flex 2 SDK, consisting of the command-line compilers and the complete class library of user interface components and utilities, was made available as a free download. Complete Flex applications can be built and deployed with only the Flex 2 SDK, which contains no limitations or restrictions compared to the same SDK included with the Flex Builder IDE.
Adobe based the new version of Flex Builder on the open source Eclipse platform. The company released two versions of Flex Builder 2, Standard and Professional. The Professional version includes the Flex Charting Components library.
Enterprise-oriented services remain available through Flex Data Services 2. This server component provides data synchronization, data push, publish-subscribe and automated testing. Unlike Flex 1.0 and 1.5, Flex Data Services is not required for the deployment of Flex applications.
Coinciding with the release of Flex 2, Adobe introduced a new version of the ActionScript programming language, known as Actionscript 3, reflecting the latest ECMAScript specification. The use of ActionScript 3 and Flex 2 requires version 9 or later of the Flash Player runtime. Flash Player 9 incorporated a new and more robust virtual machine for running the new ActionScript 3.
Flex was the first Macromedia product to be re-branded under the Adobe name.
On April 26, 2007 Adobe announced their intent to release the Flex 3 SDK (which excludes the Flex Builder IDE and the LiveCycle Data Services) under the terms of the Mozilla Public License. Adobe released the first beta of Flex 3, codenamed Moxie, in June 2007. Major enhancements include integration with the new versions of Adobe's Creative Suite products, support for AIR (Adobe's new desktop application runtime), and the addition of profiling and refactoring tools to the Flex Builder IDE.
Some themes that have been mentioned by Adobe that will be incorporated into Flex 4 are as follows:
LiveCycle Data Services (previously called Flex Data Services) is a server-side complement to the main Flex SDK and Flex Builder IDE and is part of a family of server-based products available from Adobe. Deployed as a Java EE application, LiveCycle Data Services adds the following capabilities to Flex applications:
Previously available only as part of Adobe LiveCycle Data Services ES, Adobe plans to contribute the BlazeDS technologies to the community under the LGPL v3. BlazeDS gives Adobe developers free access to the remoting and messaging technologies developed by Adobe.
Concurrent with this pre-release of BlazeDS, Adobe is publishing the AMF binary data protocol specification, on which the BlazeDS remoting implementation is based, and is attempting to partner with the community to make this protocol available for major server platforms.
Flex 2 offers special integration with ColdFusion MX 7. The ColdFusion MX 7.0.2 release adds updated Flash Remoting to support ActionScript 3, a Flex Data Services event gateway, and the Flex Data Services assembler. Flex Builder 2 also adds extensions for ColdFusion providing a set of wizards for RAD Flex development. A subset of Flex 1.5 is also embedded into ColdFusion MX 7 middleware platform, for use in the ColdFusion Flash forms feature. It is possible to use this framework to write rich internet applications, although its intended purpose is for rich forms only.
Notable sites using Flex include:
Adobe has been developing a new file format for cross application use, it has been specifically stated that the first aim was for use with Flex.