What is Flex?

Nutshell - Flex is Flash for the Enterprise Developer. You write code and the server takes care of the hard part. Flex server is a J2EE application that compiles .mxml files into .swf (ShockWave Flash files). Flex Builder is Dreamweaver on steroids. It has a design view, debugger and object viewer.

What is MXML?

MXML is the language that is actually written in when you create Flex applications. MXML is also the file extension that your flex files are saved onto the file system of the server. It is these files that are compiled into SWFs upon the first time someone calls them with a web browser.

How do I answer the question 'Flex is not a standard at our company and has no support'?

This is by far the most common question that I heard while pushing Flex. My retort is that Flex is a standards based J2EE server and all of our SAs (System Administrators) that support J2EE Application Servers (like BEA Weblogic, JRUN or JBoss - to name a few) will understand the architecture immediately and should have no problem supporting this application.

What are RIAs?

Rich Internet Applications (RIAs) provide an experience unattainable with the common HTML Request Response model. Rich Internet Applications can be created by a few competitors to Flex - but at this time all are compiled into Flash movies, or utilize JAVA. This is where I ask a couple of questions - Who knows more about Flash than Macromedia, and who are the other companies that are creating alternatives?

Name some of the competing technologies?

Laszlo, IDEA Integration Plug-in, XAML, Asperon.

All of the competing companies are no-names except for Microsoft, which is creating XAML. A couple of negatives about XAML are the fact that it will be Microsoft only and who wants to wait until 2010 to start developing RIAs?

What kind of things can I build with Flex?

All kind of things. You can build applets that reside within your current HTML based applications. You can build much larger applications that contain the entire user experience of your application. To quote a previous article on this site "RIA's are not just for E-Commerce; there is an application for them in virtually every website." (Source)

What does it mean by separating the front end and the back end?

This means that there is a presentation layer that does not do anything except present information to the user. All database connectivity and object invocation is done at a layer beyond the Flex tier.

What type of website works best with Flex?

The one that you are thinking about building. Really - any site that has a requirement for a good user experience. I would think that if you are trying to create a web site that people would like to come back to, as opposed to something like IRS.com that you might HAVE to visit, Flex would be worth considering.

What languages are spoken by Flex to interact with datasources?

Flash, and consequently Flex, can speak XML and AMF. XML can be sent to a Flex app by either embedding the XML within the SWF (via , or as an array within the application), retrieving XML by an HTTP Get (calling an html page that speaks XML or an XML file via ), XML via a Web Service (think SOAP/HTTP via ) and finally AMF (via ). AMF has the ability to request webservices as objects and can bypass the serialization process that takes place when you are calling SOAP/HTTP. Tom Link (http://www.tomlink.net) has an excellent example that compares the performance differences of using RemoteObject vs WebService in your applications.

What value does separating the front/back ends have?

This is useful because you can make modifications to either side and you do not risk damaging the other tiers of the site. For example - if you have a datasource that returns an array but retrieves its data from a SQL Server db and you want to switch to Oracle, as long as you are still providing the return data as an array - your application should work just fine. The same could be said the other way around; If you have an HTML front end (ASP or any other competitors) and you want to switch to Flex you are not making changes to the dataproviders of your site and have the flexibility to change the design technology.

What prior experience is required to develop in Flex?

Flex is a relatively easy language to learn, assuming that you are familiar with HTML, XML, and if possible, any flavor of dynamic web based scripting language (CFML, PHP or ASP). Even if you do not have experience with web based technologies you can find a Macromedia training partner, like roundpeg, that will teach you what you need to know to start developing RIAs.