XForms, three ways
DENG, Orbeon, PureEdge apply XForms to meet different app-dev goals
Of course, in an XForms proponent’s ideal world, all browsers would include XForms engines as standard equipment. There are other options out there (see infoworld.com/2556), but this ideal has yet to become a reality. In the meantime, XForms offerings from DENG, Orbeon, and PureEdge give us all a glimpse of where this progressive and versatile technology is headed.
The DENG (Desktop ENGine) project is a free XML browser that runs in Mozilla, Internet Explorer, Opera, and Safari. Built and supported by Claus Wahlers and Stefano Debenedetti, it began life under the lead of Mozquito, a German company that initiated the formation of the XForms working group. Although Mozquito no longer exists, DENG continues to be supported at http://claus.packts.net.
I tested DENG Version 1.0, the current release as of this writing. DENG’s creators are at work on Version 2, which is expected to be part of a larger XML browser framework code-named UGO (see “DENG joins a new project: Say hello to UGO”). Although I concentrated on its XForms support, DENG also implements features such as XFrames, SVG, XHTML, and more.
The DENG installation is simple and quick, amounting to unpacking a .zip that includes the Flash ActionScript files. There’s not much documentation because DENG implements technologies exhaustively detailed at the W3C’s site. DENG’s Web site includes a number of samples you can use to test your installation.
Working with DENG is extremely intuitive. You just install it; that’s it. Its capability — from the perspective of this review — is singular: It implements XForms and handles the XForms processing. Apart from the XHTML that encapsulates the XForms, no data is passed between client and server.
Unfortunately, DENG 1.0’s XForms support is incomplete. It doesn’t support schema validation, nor are the range and select forms controls implemented. The lack of these controls is a pretty serious deficit, but it does not detract from my overall favorable impression of DENG. Furthermore, Wahlers claims that the next release of DENG will be 100 percent XForms 1.0 compliant. Based on what I’ve seen, I’m confident it will be.
Orbeon PresentationServer 2.7
Orbeon’s PresentationServer is a Java framework that runs on a variety of J2EE servers to create a platform for executing XML-based Web applications. Because it runs on a J2EE server, it also provides user authentication and session management, and it integrates with Web services.
Formerly known as OXF Server, PresentationServer was released as open source last August under the LGPL (Lesser General Public License). I ran the server on Tomcat 5.0.25, though it also runs on Tomcat 4.1.30, BEA WebLogic Server 8.1, and IBM WebSphere 5.1. To install it, you simply unpack a WAR (Web Application Archive) file into your application server’s deployment directory.