Flex 2: Enabling the Next Generation of Rich Internet Applicatio

Important note:Effective with the release of Adobe LiveCycle ES, the Adobe Flex DataServices 2 server product has been rebranded as a Solution Component ofLiveCycle ES. This article was written based on Flex Data Services butwill likely work as is with LiveCycle Data Services ES. Any articlesreferring to or using ColdFusion and Flex Data Services are notcompatible with LiveCycle Data Services ES. To learn about the newcapabilities of LiveCycle Data Services ES, see the tutorials in the LiveCycle Developer Center and read about Adobe LiveCycle Data Services ES.

In October 2005, Macromedia (now Adobe) provided the developercommunity with the first look at Adobe® Flex™ 2—a new lineup ofdeveloper tools, libraries and runtime services that will enabledevelopers everywhere to build and deploy rich Internet applicationsthat take advantage of the Flash® Player runtime. Since then, tens ofthousands of developers have started to build applications with Flexand provide their feedback to us. Additionally, Macromedia became partof Adobe, opening up a whole new world of opportunities for improvingthe future of Internet applications.

With theannouncement of the Flex 2, we're proud to show the results of thedevelopment cycle between October 2005 and June 2006. By combining anintuitive programming model, a powerful Eclipse-based IDE, and a richset of J2EE-based runtime services, we believe that the Flex 2 productline provides developers the most comprehensive solution for deliveringcross-platform rich Internet applications available today. The recentlyannounced pricing structure allows developers to build and deploy manykinds of applications for free without needing to install anything ontheir servers. And recent releases of technologies like the Flex-Ajax Bridge and Ajax Client for Flex Data Servicesunder open source licenses allow developers to incrementally add Flexcomponents to existing websites and applications, whether they arebased on static HTML or Ajax technologies.

Pushing the envelope on RIA development

Inearly 2001, Macromedia coined the phrase "rich Internet application"after seeing what developers and designers were building in MacromediaFlash. It was clear that these applications extended the designlimitations and interaction constraints of traditional HTMLapplications. They didn't require a full page refresh when usersinteracted with them. They used network bandwidth efficiently,transmitting only the portion of the data that changed and minimizingthe transfer of layout information. They contained a rich array ofinteractions that allowed end users to directly manipulate data. Theyseamlessly layered audio and video into the application's userinterface. They clearly maintained their context as the user navigatedthrough the application. And, of course, they supported high-fidelityprinting.

The effect of rich Internet applications hasbeen incredible, both in breadth and depth. We're seeing everyone fromInternet hobbyists to large enterprises building RIAs—and seeing theirbusiness improve dramatically as a result. Large financial servicesinstitutions are using RIAs to solidify their brand with customers andspeed up internal business decision-making through better interactionwith mission-critical data. Online retailers have reduced shopping cartabandonment by 50% during the checkout process. Individual developershave integrated slick online mapping services with webcams posted onNew York City's traffic lights to give commuters the most up-to-dateand useful traffic information.

As customers began tobroaden their use of rich Internet applications, developers quicklyrecognized some special needs. Some RIAs need to consume real-time datafeeds. Others need to run in occasionally connected environments,intelligently synchronizing data when a connection is established. Someneed to consume proprietary binary protocols. And still others requirethat multiple clients share a single instance of data.

Basedon our work with these early adopters, we set out to deliver an RIAplatform that addressed these needs and could be extended easily tomeet the specific needs of a wide range of applications. We wanted togive developers a client runtime, development environment, classlibraries, and data services to help them:

• Be extremely productive in RIA application development
• Create expressive applications with effective interface patterns
• Deploy applications through a well-distributed, high-performance, cross-platform, cross-browser runtime environment
• Use tools and technologies that scale with the size of the project and complexity of the task

Weare thrilled to introduce the Flex 2 product line as the best way tobuild a wide range of immersive applications, from simple restaurantmenus to complex workflow systems and synchronized trader desktops.

Ifyou're familiar with Flex 1.0 or 1.5, it's very important to recognizethat Flex 2 is far more than just a new release. From a technicalstandpoint, Flex 2 introduces new capabilities that enable developersto build an entirely new class of rich Internet applications. At thesame time, Adobe Flex Builder™ 2 has been built from the ground up onthe Eclipse open-source IDE framework and now includes the Flexframework and the compiler. In addition, the ColdFusion® and Flex teamshave worked closely together to provide ColdFusion-specific integrationpoints between Flex Builder, Flex Data Services, and the ColdFusionServer.

In addition to the technical and product advanceswe've made significant changes to the way Flex 2 is packaged, priced,and deployed. The Flex framework is available free of charge throughthe Adobe Flex 2 Software Development Kit (SDK). The Flex 2 SDKincludes the command-line compiler and documentation required todevelop, compile, and deploy Flex applications that connect to any XMLand SOAP web service. It is available as a separate download and allowsdevelopers to build and deploy any application (including those forcommercial use) free of charge. We have also made available alimited-connection version of Flex Data Services 2 free of charge foruse on a single, non-clustered server. (Of course, Flex Data Services 2will be also be licensed commercially on a per CPU, per project, andenterprise license basis.) Together, these free offerings bring theindustry's most powerful cross-platform RIA technology within reach ofevery developer and every project. That's huge.

A new foundation for rich Internet applications: Flash Player 9

Flash®Player, the backbone of the Flash Platform, is also evolving to providethe foundation for the Flex 2 product line and next-generation RIAs.Over the years the player, which began primarily as a client forplaying animation, incrementally extended its scripting language(ActionScript) by adding support for portions of the ECMAScriptstandard (the same standard that drives the development of JavaScript).By the release of Flash Player 7, ActionScript implemented the vastmajority of the ECMA standard. Flash Player 9 (until recently referredto as Flash Player 8.5) ships at the same time as the Flex 2 productline. Read more about it in Introducing Flash Player 9.With it we introduced ActionScript 3.0, a powerful object-orientedprogramming language designed for productivity and performance, andbased on the next generation of the ECMAScript standard. Read moreabout it in ActionScript 3.0 overview .

Flash Player 8 (releasedin September of 2005) made great advances in the rendering engine,introducing a set of extended expressiveness capabilities (filters,advanced gradient controls, rendering performance, and so forth), andvideo support enhancements (higher quality codec, alpha channelsupport, and so forth) that are unparalleled on the web today. FlashPlayer 8 also greatly improved the APIs that enable a developer tocommunicate between applications running in the player, the browser'sHTML document object model, and associated JavaScript functions, makingit easier to add Flash components to existing web pages andapplications.

Flash Player 9 builds on the advances inFlash Player 8 by focusing on improving script execution in the virtualmachine. In fact, it includes a brand new, highly-optimizedActionScript Virtual Machine (AVM) known as AVM2 and a new version ofthe ActionScript programming language. AVM2 is built from the ground upto work to support the needs of RIA developers. The new virtual machineis significantly faster, supports full runtime error reporting andindustry-standard debugging. It includes binary socket support,allowing developers to extend the player to work with any binaryprotocol. Flash player 9 will also contain AVM1, which executesActionScript 1.0 and 2.0 code, for backward-compatibility with existingand legacy content.

With ActionScript 3.0, we haveachieved more than simple compliance with the ECMAScript standard;Adobe now chairs the ECMAScript committee and helps drive itsevolution. ActionScript 3.0 features a compilation mode for strongercompile-time type checking that provides the benefits of languages suchas Java or C#. It supports new features to streamline datamanipulation, including the E4X (ECMAScript for XML) standard, whichextends the language and adds XML as a native data type allowingdevelopers to more naturally interact with and manipulate XML. It addsregular expressions support for better text parsing and processing. Itsheds some of the ad hoc event handling schemes in the old virtualmachine in favor of a unified model based on the W3C DOM Eventsstandard. And it has significantly updated APIs aimed at theapplication developer audience.

For a complete overview of the new capabilities, check out the articles, ActionScript 3.0 overview and Introducing Flash Player 9.

The Adobe Flex 2 product line

TheFlex product line gives application developers a powerful clientruntime, programming model, development environment, and data services.It supports common design patterns, works with existing development anddeployment technologies, and provides the benefits of a modern,standards-based language. The product line contains the followingdistinct technologies:

• Adobe Flex framework and Flex 2 SDK
• Adobe Flex Charting 2
• Adobe Flex Builder 2
• Adobe Flex Data Services 2

Flex framework

Atthe core of Flex 2 is the Flex framework, which is distributed for freeas part of the Flex Software Development Kit (SDK). The frameworkbuilds on the foundation provided by Flash Player 9 and ActionScript3.0 by providing a rich class library that embodies best practices forbuilding successful RIAs. The Flex framework provides a rich set ofextensible user interface components, a flexible model for controllinglayout and user interaction, and a robust infrastructure for accessingdata from remote services and binding it to the data objects and userinterface controls.

The Flex component library includesover 100 components and containers, ranging from simple widgets likebuttons and a color picker, to advanced controls like a data grid,accordion pane, and rich text editor. Developers can construct anapplication's user interface using these built-in components, subclassthem to modify their behavior, or create entirely new components usingthe component API. Like other modern user interface developmentenvironments, Flex enables developers to take advantage of predefinedinteractions, such as draggable columns on a data grid, or hook intosome well-defined events to define application-specific behaviors.

Developerslay out Flex components with MXML, an XML-based language that providesa declarative approach to controlling an application's visualappearance. Using MXML, developers can position components, specifyconstraints to enable a more "liquid" user interface, and use ViewStates and Transitions to control how the application should respond todifferent user actions and application events. To customize the lookand feel of an application, developers can set the built-in styleproperties through Cascading Style Sheets (CSS) or attach custom visualassets using built-in support for 9-slice.

Flexapplications access data and services through a set of built-in servicecomponents. Developers can access XML data through HTTP and webservices, as well as take advantage of additional services provided byFlex Data Services, including connectivity to remote Java objects,publish/subscribe messaging, and the new Flex Data Services. Tofacilitate working with data, Flex provides a rich data-bindinginfrastructure that automatically updates the user interface when datais returned, allowing applications to remain responsive even whenwaiting for results from the server.

Take a more in-depth look at enhancements in the product information about Flex framework.

Flex Charting 2

Adobeprovides a flexible charting extension to Flex. Developers can easilyadd these data visualization components to any application. TheCharting components are dynamically rendered on the client, making iteasy to add drill-down, rollover, and other interactivity that makesyour charts even more insightful than before. The Charting componentshave a fully exposed API that allows you to easily customize thecomponents or create your own.

The charts package isfully integrated into the framework's general infrastructure foreffects, styles, data binding, and drag and drop, and will workseamlessly with Flex Data Services (see below).

Flex Builder 2

FlexBuilder 2 is a brand new tool defined from the ground up to providedevelopers with an incredibly productive environment for building richInternet applications. It provides a state-of-the-art coding anddebugging environment; features intuitive layout, styling, andinteraction design tools; and promotes good, maintainable codingpractices. Built on the Eclipse platform, Flex Builder presents both afamiliar and truly extensible set of capabilities.

Developersusing Flex Builder 2 will find tools that significantly acceleratetheir coding efforts. "Content Assist" capabilities enable code hintingfor both MXML and ActionScript. Code navigation capabilities help youfind the definition of a method or class quickly. An option toincrementally compile your application automatically on every file savespeeds up the edit-run-debug cycle. Built-in error reporting makesfinding and fixing errors easy. The context-sensitive help system makesit fast to find documentation. The advanced debugging perspective makesdebugging Flash applications efficient and enables those who alreadyuse Eclipse to debug client and server code in a single IDE. Lastly,its integration with source control systems (such as CVS) and buildtools (such as Ant) make team development easy.

Developerswill find flexible visual support for laying out controls by absoluteposition, relative position, or predefined layout rules (such asvertical, tile, and so forth). Visual design support for "View States"is an innovative feature that enables you, with very few lines of code,to visually define how the appearance of a control or the entireapplication changes in response to some event. The CSS editoraccelerates the creation of new style sheets, or integration withexisting ones, and the ability to display edited styles and skins inthe Design view as you code, shortening the update and test cycle. Italso supports seamless round tripping between hand-edited code and codegenerated by the Design view, so that a team of developers can worktogether without code conflicts.

Developers using FlexBuilder 2 can import multimedia and video produced in FlashProfessional 8. Our goal is to give teams of interactive designers,videographers, multimedia producers, and application developers thebest of all worlds. They can use Flash Professional to create the mostprecise, powerful, and expressive interactive content and media. Theycan use Flex Builder to create the most immersive applicationexperiences. Over time, we intend to strengthen the workflow amongthese tools, making working together even easier and more efficient.

Flex Builder 2 will be available as an independent product with a standard tool pricing model. Read more about Flex Builder 2.

Flex Data Services 2

InFlex 1.0 we provided a set of runtime services to aid the transport ofdata and integration with existing server infrastructures. Flex DataServices 2 takes a massive step forward by providing a set ofmessage-based services and supporting capabilities that join yourenterprise architecture and information presentation by transparentlysynchronizing data between tiers. This significantly increasesdeveloper productivity by reducing time spent writing, debugging, andmaintaining the often-error-prone code required to move data among theclient, application, and database tiers.

Flex DataServices also exposes a robust messaging infrastructure for moving databetween the client and server, and allows developers to easily createapplications that efficiently leverage real-time data, occasionallyavailable services, and very large data sets. The Data Servicescapabilities seamlessly extend the framework, allowing developers torealize the benefits with very little overhead. For example, theclient-side messaging architecture provides an elegant model for eventand data queuing and synchronization, allowing organizations to produceoccasionally connected applications with minimal effort.

Inaddition, Flex Data Services enhances our efficient, binary protocolfor data transport (AMF), and continues to support RPC-styleinteraction with web services and Java objects. For more details, checkout the Flex 2 product information and the Data services and integration section in the Flex Developer Center.

The Flash Platform: Expanding the richness of rich Internet applications

Flashhas always been at the forefront of user experiences, thanks to thecapabilities of the technology and the incredibly creative communitythat pushes the envelope of traditional design practices. The resultingadvances in user experience design are often immediately available toFlex developers. Take, for example, the recent explosion in the use ofFlash Player for online audio and video.

Flash Player isthe most widely deployed audio and video player on the market. Itallows video elements to be seamlessly integrated into the surroundingcontent or application, such as triggering video cue point events inyour RIA. It supports progressive download of short-form video filesand integrates with Flash Media Server 2.0 for streaming moreinteractive, higher quality, long-form video.

Thecommunity has leveraged these capabilities to create rich Internetapplications that break down the silos that exist today betweenapplications and rich media. Instead of having their applicationslaunch a separate media player—thereby creating a discontinuousexperience—Flex developers can truly integrate video into theirapplication's user interface and workflow. For example, training videoscan navigate and highlight particular user interface elements of yourapplication and your application can cue specific portions of a videoto play based on a user's actions. Flash video and audio streams can beincorporated into Flex 2 applications by using Flash Media Server 2 or Flash Video Streaming Service,a hosted service for delivering large-scale Flash Video deploymentsdeveloped by leading CDN (Content Delivery Network) partners inconjunction with Adobe.

Lastly, now that the merger ofAdobe and Macromedia is complete, you can expect to see interesting newinnovations to work their way into the Flex product line. As we lookforward, some of the areas we are investigating include support forreal-time collaboration, improved designer-developer workflow, andgreater support for offline applications and documents. Look for moreon our future direction on Adobe Labs in the coming months.

Thank you from the Flex team

Bynow you've seen a high-level overview of the Flex 2 product line,including Flash Player 9, the Flex framework, Flex Builder, and FlexData Services. Our goal for the Flex 2 product line is to provide thedeveloper community with a great platform for delivering the bestapplication experiences to their customers.

We made theprerelease versions of Flex 2 available so the developer community atlarge would have an opportunity to have an early look at our direction,and to provide feedback. On behalf of the Flex product teams, thank youfor visiting Adobe Labs,downloading our beta, and getting involved. If you're a ColdFusiondeveloper, be sure to download the additional ColdFusion 7.0.2, whichcontains connectivity to Flex.

Visit the Flex Developer Center and flex.org to stay up to date and discuss your ideas and questions with other developers on the Adobe Flex Forums.To help make your initial experience with Flex 2 a productive one, wehave provided a series of sample applications, tutorials, and otherresources you can walk though before venturing "off road."

Whenyou've seen what's possible with Flex 2, please tell us what you think.We look forward to collaborating with you to build a set of productsthat enables you to change the face of Internet applications.

Resources for Flex 2

• Flex Developer Center
• Flex.org
• Flex 2 sample applications
• Flex Quick Starts
• Flex 2 SDK release notes
• Flex Builder 2 release notes
• Flex Data Services release notes
• Flash Player release notes
• Flex 2 installation instructions
• Migrating Flex 1.x applications to Flex 2
• Documentation: Getting started with Flex 2

About the author

Flex 2: 打开下一代富互联网应用之门

Flex 2:  打开下一代富互联网应用之门

David Wadhwani

Adobe