GWT Java AJAX Programming

simon_kehler writes "The Google Web Toolkit (GWT) is a Java AJAX framework that provides an easy to use programming paradigm for web developers using the Java programming language. It is one of the more recent entrants into this field, but has been gaining a lot of traction and popularity. GWT Java AJAX Programming authored by Prabhakar Chaganti and published by Packt Publishing addresses the use of GWT to build ajaxified user interfaces. The author gently introduces the reader to GWT and then leads the reader through a series of tasks, each of which shows how to perform an useful action with GWT." Read below for Simon's review.

GWT Java AJAX Programming
author	Prabhakar
pages	240
publisher	Packt Publishing
rating	8
reviewer	simon Kehle
ISBN	1847191002
summary	A great book for learning the different facets and features of GWT

I am a software architect working for a startup that is evaluating the use of GWT for a new project. I lead a team of experienced Java developers that are comfortable working with Swing and have reasonable familiarity with Struts. We have looked on with envy at all the nice things you could do with the AJAX integration built into web frameworks in languages such as PHP and Ruby. When I came across GWT we decided to take it for a spin and see if your team would be comfortable using it. The documentation that comes with the GWT download is a bit sparse. I was looking for a more in depth intro to the framework and came across this book. this seems to be the first print book on the GWT framework.

The book is divided into ten chapters. An introduction to GWT and its download and setup is provided in the first chapter. The author then shows how to create random quote GWT application in chapter 2. This is a nice example that immediately gives you the flavor of what its like to work with GWT. It shows you the steps involved in writing and running a simple GWT app. Chapter 3 details the service interfaces that you need to create as a part of any GWT application. These are the heart of how the AJAX mechanism works in this framework. Chapters 4-6 go through a lot of tasks that show you how to create increasingly complex user interfaces using the GWT framework. Chapter 7 deals with creating custom widgets that can be shared across applications. Unit testing for GWT applications is covered in chapter 8 (Yes, you can unit test your AJAX apps!). I18N and client XML support are dealt with in chapter 9 and finally chapter 10 shows how to deploy your applications.

This book moves along at a fairly rapid pace and is a quick read. The examples chosen for the tasks are well thought out and show different features in GWT. There are several really cool and innovative examples in this book: Password strength checker, uses colored check boxes to visually show the strength of a password. A very different way of using a check box. Dynamic Lists, change list entries as selections change. Flickr label, recreates the cool label widget that was made famous by Flickr. Sticky Notes, you create post it notes in your browser and drag them around to place them as you want (uses GWT drag support.) Mona Lisa jigsaw puzzle, rearrange Mona Lisa (uses GWT drag support.) Moo.fx, uses moo.fx javascript library for effects (uses JSNI.) Color Selector, integrates Rico Javascript library into GWT (uses JSNI.) Calendar, a very cool mac os x like calendar widget (Creates a compound widget.) Weather, another widget (creates a compound widget.) I18N, displays the country flag based on the locale (uses i18n support.)

I had played around a bit with GWT before. So some of the things in the book were not new to me, but there were several things that I found very useful. GWT provides a way to integrate Java and Javascript (you can call into Java from JS or from JS to Java) called JSNI (Javascript Native interface). The JSNI examples in this book showed how to integrate with moo.fx, Rico and scriptaculous libraries. This was great as we have some homegrown Javascript libs that we would like to continue to use even when we move to GWT. If we can try to hook those in and call them from GWT, that would be sweet! The ability to create widgets that can be shared across applications is very important to our project. The author creates two widgets in chapter 7 — calendar and weather. Both of these were very cool and reminded me of my mac desktop widgets! The weather widget uses Yahoo's weather service to retrieve the information that is displayed. Again, very nicely done. The ability to unit test is another thing that is crucial for us. GWT leverages and extends JUnit to provide this support. However, this is one of the parts of GWT that people do not seem to be using much. Searching on the GWT forums reveals as much confusion about this topic. This book contains a chapter that shows how to unit test a GWT application. The examples are quite simple, but the creation of test suites was a good one, as I had struggled with that before. I really liked the author's coverage of deployment. He first shows how to manually deploy a GWT application. this gives you a feel for whats involved and what's going where. Then he automates that using ant and finally shows how to deploy from within eclipse. This is very useful as I have tripped over deployment before.

Overall, this is a well written book that was very useful to our team. There were a few examples that we had implemented differently than the author — table sorting, paging and in place editing of the tree nodes. I18N is a big topic and the author covers only one way to use it. It would have been nice to have a complete chapter devoted to that topic, as this is a topic of particular interest to us as we work with a multitude of languages. This is a very developer oriented book and assumes that you know Java, HTML, some Javascript and some CSS. Of course if you did not know those topics, you probably wouldn't be too interested in GWT! This is not a book that dives into the internals of how GWT works or tries to impress you with all the nitty gritty of the GWT architecture. The author provides you with ways in which you can accomplish most common tasks that require GWT. They may not be the only way to do things using GWT but it gets you comfortable using GWT and thinking about how you would actually apply it for your problem. I really enjoyed reading this book and its focus on the practical side of using GWT.

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AJAX is Irrelevant

[Anonymous Coward]

Actually, it's worse than irrelevant - it is a real pain. From a lead programmers point of
view in a web-based billing environment, it's a chore trying to keep the kids focused on the
(perhaps boring) task at hand and keep them using clean, simple, classic CGI programming
techniques. Every so often, someone wants to start using AJAX and automatic form reposting
and a bunch of stuff that makes their code unreadabale and unmaintainable by the rest of the
crew. Invariably, I ask them to describe the problem that could not be solved with a
snippet or two of Javascript, and invariably, they start spouting nonsense that basically
boils down to them wanting to fiddle around with AJAX.

If you ever start waking up thinking that perhaps you'll take a gander at AJAX, just repeat
three times: "I do not need AJAX for anything", take your shower, get a nice cup of coffee,
and continue on with your day.

Re:All of these frameworks are mostly overkill

[AKAImBatman]

That was NOT a simple example. That was a full-up demo with all the bells and whistles in place. You don't make your point by showing the bells and whistles! The message ends up getting lost in all the excess code.

Oh, and you do realize that setting window.status no longer works on many browsers? It is considered a security hazard.

I prefer Yahoo's YUI

[mha]

I was looking for which framework to use. I didn't look (further) at Google's offering because I wanted a JS framework, not Java, so I cannot comment on it. Yet I would like to make a posting to point out my personal favorite, the YUI, and how I got there.

First, on the page http://developer.yahoo.com/yui/theater/ [yahoo.com] the Yahoo "JavaScript Architect" Douglas Crockford gives some really *excellent* learning presentations on JS and the DOM that convinced me that there are really knowledgable people whos philosophy I like too.

Second, the license is BSD - it can hardly be any more free.

Last, if I have to rely on a framework I want to be sure it stays around. So even if some of the others are nice too and would fit, I must say I trust Yahoo a lot more to stay around and improve their framework - especially since they use it themselves for everything they do.

I also must say that I wasn't impressed at all when I finally tried GMail a few weeks ago, as a regular user of Yahoo mail for all my "public" mail (my own domain has 4000 email addresses left but I prefer Yahoo because of the excellent Spam-filter and only use my own domain-address for close friends) I find the Yahoo mail interface superior and much nicer.

What's more, there's YUI-ext, an extension for YUI (and now available for Jquery too), which provides some great-looking and very functional add-ons: http://www.jackslocum.com/blog/index.php [jackslocum.com]