The previous section traced the development of a simple Web application using present-day technologies predicated by the HTML forms architecture. The questionnaire application evolved from a simple stand-alone CGI script to a more complex Web application consisting of software components dedicated to managing the application state within a servlet, markup pages designed to create the user interaction, and navigation components designed to connect the various views with the application state.

A form -- whether a sheet of paper or a web page -- represents a structured exchange of data. Web services, as typified by emerging standards like SOAP, WSDL, and UDDI, is an excellent approach to exchanging data in a structured way, although usually the exchange is between machines. Since computers are much better at, well, computing, web services is an important and overdue development in the evolution of the Web. Nevertheless, web services applications exchanging information only between machines isn't very interesting: lots of electronically accessible information originates with ordinary human beings.

A pdf presentation about XForms and the future of XML input.

This package, distributed under the name Xforms4Perl, provides an extension to Perl that opens up almost 100% of the Xforms GUI library API to Perl scripts, thus allowing those scripts to build and interact with Xforms graphical user interfaces. It also provides some value added features, such as automatic initialization of object classes, that are not present in the native Xforms library (see "Value Added Features" below).

XForms is a new XML-based markup that addresses many of these shortcomings

You may be wary of deploying XForms because it currently doesn't have much browser support. Most browsers will support XForms down the road, but for now, the only reliable and scalable way to implement it is through a server-side mechanism.

XFORMS is a toolkit to help you write programs with a graphical user interface (GUI). It is a re-write and extension of the popular GUI toolkit, FORMS, which was for GL based systems only. It is available for all the mainstream Unix systems as well as the popular PC versions of Unix.

Figure 2-3 shows the initial state of the user interface produced by this portion of the XForms code. Figure 2-4 shows the result of toggling the switch, revealing the form controls for entering the buyer and seller information.

The XForms home page calls XForms ``a GUI toolkit based on Xlib for the X Window System. It features a rich set of objects, such as buttons, sliders, and menus, etc., integrated into an easy and efficient object/event callback execution model that allows fast and easy construction of X applications.'' With this first of three articles on XForms, you can ease into programming for X without having to know exactly what ``object/event callback execution'' involves.

Part 3 shows us the means to give our game simulator a more professional appearance and to add a few goodies.

Today's Web applications are being deployed far beyond desktop PCs: to mobile phones, PDAs, and appliances. Even traditional client/server applications now often require mobile and wireless capabilities.

This example shows an xForms timesheet application rendered in IE 6™ with the OnForm's engine. Note that xForms "Triggers" have been incorporated to save the entire file to a filepath specified by the user (obviously the user needs access permissions maintained outside the form if saving, for example, to a network), to load a previously saved "instance" (eg you could save details for name, dept, employee no and a standard working week, load this into the form and just add the overtime for that week), and to submit the completed form, as a valid xml document, to a server.

The second level of abstraction tied into XForms is the creation of models. A model represents an internal entity into which the interface (through the components) provides a window. Programming languages such as C# or Java usually reflect the model using classes and the relationships between classes.

As you have seen in various recent issues of Linux Journal, the Xforms library allows you to add a powerful GUI to your C or C++ programs using a simple, intuitive API. The functionality and elegance of Xforms GUI is comparable to Motif's, yet the Xforms libraries are free if used non-commercially.

You may be wary of deploying XForms because it currently doesn't have much browser support. Most browsers will support XForms down the road, but for now, the only reliable and scalable way to implement it is through a server-side mechanism. For the purposes of this article, I'll walk you through using XForms via the Java Framework.

You've already seen how various XML technologies integrate seamlessly with each other when it comes to XForms. In fact, in the last part of this tutorial, I showed you how to re-use an XML Schema datatype definition in an XForms model, and how to use XPath expressions to reference and bind instance data with the XForms user interface.

This is a very exciting time to be a developer. Mobile and wireless devices have rapidly improved, and now ship with better memory, display, and connection capabilities than ever before. Increasingly, Oracle customers want to leverage these improvements to "free" their mission-critical applications (and their workforce) from desktop PCs.

There are 3 defaults (xsl:params) in the template which control the formatting of lists and textareas. The parameters and their defaults are:

The Solution: XForms - The World Wide Web Consortium (W3C) became aware of the limitations inherent to HTML forms and perceived an increased need to develop a new, non-backwards-compatible specification for Web Forms. In response, the W3C created a subgroup under the HTML Working Group, the group responsible for advancing the HTML standard to develop some solutions.

The XForms home page calls XForms ``a GUI toolkit based on Xlib for the X Window System. It features a rich set of objects, such as buttons, sliders, and menus, etc., integrated into an easy and efficient object/event callback execution model that allows fast and easy construction of X applications.''