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Posted by editor on June 21, 2007 at 7:19 AM PDT


Let your clients take some of the load off your webapp server

In our second webapp feature article of the week, we take a look at the RAJAX project, which allows you to move more of your webapp out to the client side. As the project page says, "The main goal is to create a library that at runtime will generate a proxy JavaScript class to a server side Java class allowing the web programmer to invoke remote methods in the local JavaScript object."

Paulo Lopes offers an introduction and tutorial on RAJAX
in todays Feature Article,
An (Almost) CPU-Free MVC Pattern with Ajax . Paulo says that with RAJAX, you can move some of your model and view logic over to the client, for example using XSLT in the browser to do client-side rendering and presentation rather than forcing the server to do that work.

But is this the right idea? Paulo says:

It is clear we can do it, but why we should do it is the next question to arise. Everything works fine with the current paradigm, so why make a change? To me, it is clear that this change should be made for the same reasons we started using Ajax in the first place: web applications were slow, suffered from network latency, etc. Ajax brought the data layer to the web browser; now we bring the layout layer to the web browser, too. By doing this, we get a clear separation of code and data, and simplify the code necessary for displaying a view in the browser by using XSLT transformations in a template instead of a big HTML file.

The more the clients do, the easier it should be for your server to scale. What do you think? Is this a workable approach for your webapp?


In Java Today, InfoQ reports that the first GNU Classpath/Sun Java hybrids have begun to appear. In Hybrids Combine GNU Classpath and OpenJDK, Xandy Johnson reports "The hybrids combine GNU Classpath with Java code that Sun has recently released under the GPL either to improve an existing project or to further the goal of having a completely Free JDK." The article covers projects from IKVM, CACAO, and Red Hat.

Jersey is the open source JAX-RS (JSR 311) Reference Implementation for building RESTful Web services. Jersey also provides additional APIs and extension points (SPIs) so that developers may extend Jersey to suite their needs. Jersey is currently available as an early access implementation. Jersey cannot go to version 1.0 until JAX-RS reaches the final release and is an approved JSR. Until that point Jersey will track the JSR 311 API and will regularly update according to 311 Expert Group agreed snapshots of the API

In the latest Java Mobility Podcast, entitled A Swarm of Cheap Robots on Mars (Or Wherever You Need Them) , Bruce Boyes, CEO of Systronix, describes TrackBot, a small robotic device with built-in sensor modules that provide beaconing, obstacle avoidance, spatial awareness, communication, and navigation. Add a SunSPOT device to TrackBot, and the result is a powerful but affordable strategy for large-scale deployments in swarms and collaborative robotic behavior (see also TrackBot on YouTube).


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