VoiceXML « XML « Java Articles

And the list goes on! Web frameworks offer you a way to get all the benefits of servlets, and typically support JSP pages as well. All you need to do is plug your existing JSP pages into a framework, and your VoiceXML application suddenly handles errors better, provides logging and support for multiple languages, has an easier time communicating with EJB components and databases ... and do anything else that the framework provides. All in all, if you've gone to the trouble of using a controller servlet, you'll almost always benefit from using a full-fledged Web framework.

In the next article in this series, you'll add another tool to your bag of tricks and techniques: JavaServer Pages (JSP) technology. It's fairly easy to get a JSP page to output XML, and VXML is just one more flavor of XML. In many cases, you don't need the processing capabilities of a servlet: in many cases, JSPs can provide you with dynamic programming abilities and spare you the overhead of writing servlet code. Be sure to come back next month for more on servlets, JSPs, and dynamic VoiceXML applications.

The ability to serve telephones through existing -- or slightly modified -- Web applications is a powerful idea, and one that many Web developers are eager to explore. The most important thing to know about Web and phone applications is that you can use virtually the same technology stack to create both. HTML, XHTML, and XML are three of the most common technologies underlying Web interfaces, and VoiceXML (or VXML) is a closely related technology that makes Web interactions available to phone clients. JavaServer Pages and servlets, PHP scripts, and Ruby applications can all respond to phone requests as easily as those that come in over a handheld or Web browser. In this article, I focus on using the Java platform to serve simple VoiceXML applications, but you can apply much of the discussion equally to PHP, Perl, or your programming language of choice.

One of the best ways to eliminate some of these issues is to create a set of proven tools and libraries for use in your VoiceXML applications. For example, if you develop an approach for handling path constants (like /pages/menu.vxml), and test that on multiple devices, then you really don't want to mess with that piece of working code. Of course, if that code is integrated into your application -- just lines of code inside other application-specific lines of code -- you've got a problem: you can't easily reuse your working, tested code on new applications, even if they need the same function.