Justin Gehtland

By Justin Gehtland

Ajax applications have unique architectural challenges and opportunities. This presentation will show you how to take advantage of the Ajax's strengths, and work around its quirks.

Topics covered will include

Selecting an Ajax toolkit

Dealing with browser differences

Handling the "Back" button

Degrading gracefully

Marshalling data

Managing XML

Minimizing roundtrips--or not!

When Ajax isn't enough

Packaging and deployment

Prior exposure to Ajax and JavaScript is very useful, but not required.

By Justin Gehtland

Web applications have traditionally been a sort of Faustian bargain, yielding the high-quality user experience that desktop applications can deliver in exchange for incredibly easy deployment and lower support costs.

One of the arguments against creating rich HTML/JavaScript has been how difficult they can be to write and maintain. You will see how to adapt modern Java web frameworks such as JavaServer Faces and Tapestry to ease both the creation and maintenance of these types of applications.

With Ajax we can get a lot of the best of both worlds. Now our web applications can be powerful, usable, an easily deployed!

Web applications have traditionally been a sort of Faustian bargain, yielding the high-quality user experience that desktop applications can deliver in exchange for incredibly easy deployment and lower support costs (i.e., no client software to install, upgrade, and test on every conceivable desktop configuration).

It turns out that these qualities need not be mutually exclusive. As several recent high-profile web applications such as Google's GMail have shown, modern browsers (e.g., Internet Explorer 6, Mozilla/Firefox, and Safari) are capable of rendering web applications with highly dynamic and compelling user interfaces -- fetching data from a server without page refreshes, animating and manipulating page contents on-the-fly, and all without resorting to third-party plug-ins like Flash. The line between a ""web"" application and a ""desktop"" application is blurring.

Let's blur it some more. Another major limitation of web applications is the lack of ability to function in a disconnected (i.e., off-line) mode. It turns out that this too is quite possible with the right architecture -- a web application can continue to function in a modern browser even in the absence of an Internet connection. And when the connection is re-established, data collected while in off-line mode can be uploaded to a server.

Developers seeking practical, real-world advice for creating next-generation, rich web applications won't come away from this presentation disappointed.

By Justin Gehtland

This presentation covers JavaScript from the perspective of an Ajax programmer. We assume that you may be using an Ajax toolkit, but still need to be able to read, modify, and test the JavaScript code in your application. You will learn the common idioms of JavaScript by looking at working code from the Ajax toolkits themselves.

All Ajax programmers need to know JavaScript. Toolkits will do some of the work for you, but your own JavaScript will differentiate your applications from others. A reading knowledge of JavaScript is also necessary when selecting an Ajax framework, and for testing and debugging applications.

We'll go straight to the interesting parts of JavaScript programming:

* Prototype-based inheritance
* Functional style
* Dynamic evaluation
* In-browser testing

We'll demonstrate these concepts using popular Ajax frameworks such as Dojo, Prototype, script.aculo.us.

By Justin Gehtland

Learn to simplify Ajax development with Prototype through a series of real-world examples. Along the way, learn to code in Prototype's modern JavaScript style, taking advantage of Prototype's extensions to JavaScript's object model

Prototype deserves its fame for Ajax support, and for easy integration with the Rails platform. In this presentation, you will learn to simplify Ajax development with Prototype as we work through a series of examples that demonstrate:

* using Ajax.Request to manage XMLHTTPRequest

* automatically updating pages with Ajax.Updater

* polling with PeriodicalExecuter

* managing forms with Form.serialize

* responding to inputs with Event.observe

* simplifying DOM updates with Insertion

But there's more! Prototype exemplifies modern JavaScript coding style. You will see how to take advantage of "Prototype as JavaScript++" by

* using JSON for parameter passing

* defining classes with Class.create and Object.extend

* using Ruby-inspired extensions to the JavaScript object model, such as Array.each

By Justin Gehtland

JRuby is not one, but two great technologies: the Ruby language, and the Java Virtual Machine and libraries. In this talk you will learn the basics of programming JRuby, and how to integrate JRuby code into existing Java projects.

Ruby is a great language, but you cannot afford to throw away you investment in existing Java libraries. And you don't have to. JRuby is a sufficient subset of Ruby to be far more expressive and productive than Java. Plus, JRuby's integration with Java means that you can call your Java libraries.

We'll look at Ruby basics, at calling Ruby from Java, calling Java from Ruby. We'll also explore the current limitations of JRuby, which ones are likely to be lifted in the future, and why.