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Posted by editor on August 25, 2005 at 7:43 AM PDT

Simplifying AJAX client-server connections

Feel free to jump on the AJAX bandwagon. Surely you've heard of AJAX by now, and if you haven't, the concept can be expressed in two words: Google Maps. Notice how when you click arrows or the map and satellite buttons that the whole page doesn't reload, and that only part of the page refreshes, and quickly? Mostly done with client-side scrpiting and newer browser features. Why it's almost as rich an experience as (gasp!) a Java applet.

And the name? Dreadful. Short for "Asychnronous JavaScript with XML", which tells a user how it works, not what it does. I guess there wasn't a clever way to make a contraction out of "You know, like Google Maps".

Problem is, pleasant as this is for the end-user, it's notoriously difficult to wrangle the XMLHttpRequests, parse DOM's and do the rest of the client-side work, not to mention keeping things in sync with the server side.

Direct Web Remoting, hosted on, offers some help. Creator Joe Walker says its mantra is "Easy AJAX for Java":

DWR is a Java open source library which helps developers wanting to write web sites that include AJAX technology. It allows code in a web browser to use Java functions running on a web server as if it was in the browser.

In the Feature Article, Developing AJAX Applications the Easy Way, Joe develops both sides of a chat system with DWR, starting with a simple servlet and, from that, the client-side JavaScript calls that look like simple method calls. The resulting system is just 100 lines of code, client and server.

Roger Kitain's announcement of
Open JavaServer Faces tops ... in today's Weblogs.
"I'm pleased to announce that Sun's implementation of JavaServer Faces is now open source, and it is available under the Common Development and Distribution License (CDDL)."

William C. Wake continues his conference summary in Agile '05 conference, part 2:
"More from the Agile 05 conference... John Major described a project that was doing custom programming of lab workflows as part of the Human Genome Project. This was an environment with lots of churn: biology, instruments, J2EE."

David Walend's tutorial Connecting to a Command Line Process addresses challenges working with Graphviz:
"Part of this project was adding a tographviz package to JDigraph to encapsulate interaction with the dot language and the Graphviz command line. I built some fairly elaborate code to wrap around the Graphviz command line. I created the class to bundle it all up. It makes for a nice blog article."

In Also in
Java Today
the O'Reilly Network databases site has picked up on Edmon Begoli's ITToolbox blog entry Use JSTL for conditional row coloring: "This entry is for J2EE Web Developers. I will provide an example on how to do an interleaved row coloring for the tabular data display. I will use JSTL 1.1 for JSP 2.0 syntax."

Still on Java 1.4? "The J2SE 1.4 platform was great, but J2SE 5.0 is even better. Although you may not need to migrate your product to this updated platform, you may want to move anyway." The SDN article Reasons to Migrate to J2SE 5.0 (Tiger) summarizes the language changes, new and enhanced class libraries, tool support, desktop enhancements, and other reasons to make the switch to Tiger.

In Projects and
Dick Wall's article Building a J2ME Application in NetBeans 4.1 "will show you how to use NetBeans 4.1 and the Mobility Pack to write a Java Mobile Edition application quickly and easily. It will demonstrate the simple GUI creation and storage facilities available to a mobile application developer."

From the Java Enterprise Community: the Java BluePrints Solutions Catalog project has announced its latest release. This version covers AJAX, web services in a service-oriented architecture (SOA), web tier design with JSF, and business tier design. The catalog can be downloaded from the project site.

In today's Forums,
calum is interested in some
URLClassLoader changes:
"It would be really helpful to be able to selectively remove entries from the jar: protocol scheme used by URLClassLoader - having a URL -> jar cache is okay except when you want to indicate that a new version has been deployed and you want to update it in the cache. Currently, to get the new version you have to restart your app. This is really important for RMI applications, etc."

The Your Java Career forum has started a discussion of
Desktop Careers:
"Is it practical to have a career focusing solely on Java Desktop development? What kinds of applications do you build, and what GUI toolkits are you using? Do your applications run on multiple platforms? This topic is for everyone who gets paid to know AWT, Swing, SWT, JGoodies, etc., and whose work launches with a double-click, not as part of a server's startup script."

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Simplifying AJAX client-server connections