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Features Are Jammin' It's hard to go wrong with Jamba. Similar to Microsoft Visual Basic's approach, Jamba provides a visual environment for developing Java-based Web pages. With simple mouse points and clicks, you can choose any number of objects and lay them out on a "canvas." The available object list is extensive and includes the usual check box, radio button, pu sh button, graphic, text field, combo box and list boxes. To add more buzz to your home page, though, you will want to use the Image Strips, timer, Common Gateway Interface (CGI), mail, FTP, animation, hot spots and browser objects available. Once an object is placed on the canvas, you can manipulate its various properties with ease.

When you are satisfied with your design, Jamba compiles your objects and creates an associated HTML page that contains the appropriate applet tags. Although this approach is powerful, it doesn't let you see the Java source, and you cannot change the internals of the objects provided. Nevertheless, the result is an applet that is embedded within an HTML page. If you wish, the HTML page can include any number of HTML tags, JavaScripts or other applets.

Imagine that you want to create an image strip (low-overhead animation) that is displayed when the mouse is over it (the mouse pointer is over the image, but not actually clicking on it) and hides itself when the mouse is off i t. This is not something you can do with straight HTML and requires a good deal of Java programming if you do not use Jamba. I started by using the bundled Image Lab to capture a variety of images off my desktop. You also can use scanned images, or images from any source. I then used Jamba Animator (available separately from Aimtech) to combine the images into a strip that I saved to a disk file. Back in Jamba, I added an instance of an object, called Image Strip, to the canvas. I edited the properties of the object, so it would point to the actual disk file containing the Image Strip.

You can associate a to-do list with the Image Strip because it lets you link certain events with actions. In this case, I was interested in the event called Enter, which signifies the mouse pointer moving over our object. One of the actions available to the Image Strip object is an autoplay action, which, as the name implies, plays the Image Strip and starts the animation. With absolutely no programming and just a few mous e clicks and keystrokes, the action starts when the mouse enters the object and stops when the mouse leaves. I asked Jamba to compile my work and few moments later, I had an applet and an HTML page that contained a tag pointing to my new applet.

It's a nice feeling when you know that the hardest part of animating your page is creating the animation--Jamba does the rest. Best of all, there is no need for plug-ins or long download times. (The resulting classes are small, which is an improvement over the first version.) Steps are simple and fast and have no code. To view the results of my crafting, I used the bundled Jamba Viewer (which is actually Sun Microsystems' applet viewer). I also had the option of specifying a browser, such as Netscape Communications Corp. Navigator or Microsoft Internet Explorer, to run the applets within.

The Image Strip is only one of 20 available objects. Another choice, a browser object, lets you navigate the Internet. You can place various browser objects in your Web page, e ach serving as the action associated with one or more events. For example, clicking on your Image Strip (an event) lets a browser object jump to a specified URL (an action). The objects that you put in your canvas, and that eventually make up your page, are presented within Jamba in a tree view, so you can easily understand the i nteraction among all your objects.

Amazing Animated Pages Once you are a more experienced Jamba user, you can create nifty applets from scratch; if you're a novice, Jamba wizards--a new addition--can guide you through design. The well-thought-out wizards let you create complex designs with ease. Aimtech's documentation--provided in HTML format--is helpful and leaves few questions unanswered.

As part of my testing, I asked a non-programmer user to build an attractive page with Jamba. In about half an hour, he had a very cool page with audio and animations--a feat that normally would have taken him days. Another new feature in Jamba 2.0 is Timeline Animation, which both the nonprogrammer and I used with ease to create complicated, path-based animations. To make Jamba worth your while, you must use its advanced features. Each object can be associated with any number of user-defined variables. Those variables can be used in conditional if-then statements to provide alternate content, depending on how users are navigating the site.

Let's say you create a shopping cart applet. You can drag an item you wish to buy to the cart and use your own user-defined variables to keep from adding the same item to the shopping cart twice.

In addition, you can use e-mail objects and FTP objects to return information to the server without having to do any server-side programming. More advanced users can use the CGI object--in conjunction with server-side CGI programs--to create more powerful user interactions. You can place a data object in your page to collect data from the user. The data is then transferred via the FTP object to an FTP server, where it is appended to the file of your choice. This is a simple data collection mechanism that does not replace Java Database Connectivity (JDBC), a feature that Aimtech promises to add to Jamba (as an add-on tool) in the near future.

You can use Jamba to spice up your corporate site, because it provides multimedia capabilities in a snap, while minimizing error potential and lowering maintenance costs. Neat animation, events/action pairs and powerful predefined objects not only enliven your page, but also make it much more useful and functional.

Ahmad Abualsamid is a server systems engineer at Epic Systems Corp. and a doctoral student at the University of Wisconsin-Madison. He can be reached at sami@maf.wisc.edu.