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Practical Ajax Projects with Java Technology
Simon P. Chappell writes "Is there anyone left in our industry that hasn't heard of Ajax, the ultimate client-side technology for web developers? Like many, I've read several books on it and now I'm even brushing up on JavaScript so that I can try it out. There is, however, an aspect of Ajax that often seems to get lost in the rush to play with the new browser tricks; Ajax enhanced web applications still need to work closely with server-side components. To even up the balance of books that concentrate on the browser end of Ajax, Apress brings us Practical Ajax Projects with Java Technology by Frank W. Zammetti.
Practical Ajax Projects with Java Technology
author
Frank W. Zammetti
pages
504 (16 page index)
publisher
Apress
rating
9 out of 10
reviewer
Simon P. Chappell
ISBN
1590596951
summary
A useful and practical book for those wishing to write web applications that combine Ajax front-ends with Java technology on the server-side.
This is a book for anyone developing web applications with Java server-side components. It does assume a minimum level of Java ability, but not that you should know any specific frameworks. If you know basic Servlet and JavaServer Page programming, then you'll be fine for working your way through the frameworks presented in the book.
The book is divided into two parts. The first part is just three chapters and covers the principles of programming using Ajax and Java. Chapter one is the "hurrah for Ajax", obligatory examples and brainwashing. A discussion of the "classic web" and its problems leads into examples of the new web and Ajax enhanced websites. Chapter two is an introduction to the technologies behind Ajax for those who may be less familiar with JavaScript, the DOM, XML and parsing XML using JavaScript and Cascading Style Sheets (more usually known by its acronym CSS). Don't expect to learn these technologies from scratch out of this chapter, but if you have some amount of exposure to them, it will remind you of all the bits that you'll need for Ajax. Chapter three then does a similar thing for the server-side Java technologies. Again, if you snoozed through Java classes at school, don't expect this to get you caught up, but it will refresh your memory on the useful pieces.
The second part of the book holds the seven example projects. These are the meat of the book, given that the title promises practical projects and I think that the book pretty much delivers on its promise All seven projects are interesting; six are practical and the last one is just good old fashioned fun. The projects build in terms of size, so the first one is the simplest and the game, coming last is the most complex. The first project is a type-ahead suggestion engine, modeled after Google's Suggest. Next we have an Ajax-based webmail client. Chapter six builds a RSS newsfeed reader (because, as the book says, every Ajax book has to have one). Chapter seven is a photo sharing application, which, while it may not compete with Flickr, is quite usable for its size. Chapter eight is an organizer. Umm, needless to say you'll either love this or ignore it. (What can I say? If I was organized enough to use an organizer, I'd be organized enough not to need it!) Chapter nine brings yet another chat program to the world.
Last, but as the phrase goes, not least, chapter ten is the grand finale of the example projects. As befits the author's fine sense of humor, the final project is a game; Ajax Warrior! This application has graphics designed by a professional graphic artist and looks far above any other example application that I've ever seen.
As soon as I saw that Mr. Zammetti had written a book, I rushed to be the first to volunteer to review it. This will need no explanation to members of the Struts mailing list, but for the rest of you it might help if I explain that he is that wonderful combination of a funny and helpful guy. I knew that anything he wrote was going to be first rate technically and was also going to be written in a light and relaxed style; always a winner in this kind of book.
I liked the fact that Mr. Zammetti covers a number of approaches to writing both the client and server-sides of the applications. For the server-side of a number of the applications, he uses plain JavaServer Pages, yet for others he uses industry-leading frameworks including WebWork and Struts. On the client-side he continues to mix it up, with some applications using "naked" Ajax, others using DWR, AjaxTags from Java Web Parts, DWR, Dojo, JSON and Prototype.
One more thing to like about the book is that the applications actually look very nice and quite professional. Perhaps the folks at 37signals shouldn't be nervous, but Mr. Zammetti has certainly raised the bar for the appearance of example applications for books.
The flip side of the use of multiple frameworks and Ajax libraries is that all of the breadth means reduced depth. Each of the frameworks and libraries is introduced and demonstrated, but then just as it begins to get interesting, it's off to the next one. If you're looking for more depth in each introduced item, then this book may not be for you.
In conclusion, this is a useful and practical book for those wishing to write web applications that combine Ajax front-ends with Java technology on the server-side. Strongly recommended.
You can purchase Practical Ajax Projects with Java Technology from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
This is a book for anyone developing web applications with Java server-side components. It does assume a minimum level of Java ability, but not that you should know any specific frameworks. If you know basic Servlet and JavaServer Page programming, then you'll be fine for working your way through the frameworks presented in the book.
The book is divided into two parts. The first part is just three chapters and covers the principles of programming using Ajax and Java. Chapter one is the "hurrah for Ajax", obligatory examples and brainwashing. A discussion of the "classic web" and its problems leads into examples of the new web and Ajax enhanced websites. Chapter two is an introduction to the technologies behind Ajax for those who may be less familiar with JavaScript, the DOM, XML and parsing XML using JavaScript and Cascading Style Sheets (more usually known by its acronym CSS). Don't expect to learn these technologies from scratch out of this chapter, but if you have some amount of exposure to them, it will remind you of all the bits that you'll need for Ajax. Chapter three then does a similar thing for the server-side Java technologies. Again, if you snoozed through Java classes at school, don't expect this to get you caught up, but it will refresh your memory on the useful pieces.
The second part of the book holds the seven example projects. These are the meat of the book, given that the title promises practical projects and I think that the book pretty much delivers on its promise All seven projects are interesting; six are practical and the last one is just good old fashioned fun. The projects build in terms of size, so the first one is the simplest and the game, coming last is the most complex. The first project is a type-ahead suggestion engine, modeled after Google's Suggest. Next we have an Ajax-based webmail client. Chapter six builds a RSS newsfeed reader (because, as the book says, every Ajax book has to have one). Chapter seven is a photo sharing application, which, while it may not compete with Flickr, is quite usable for its size. Chapter eight is an organizer. Umm, needless to say you'll either love this or ignore it. (What can I say? If I was organized enough to use an organizer, I'd be organized enough not to need it!) Chapter nine brings yet another chat program to the world.
Last, but as the phrase goes, not least, chapter ten is the grand finale of the example projects. As befits the author's fine sense of humor, the final project is a game; Ajax Warrior! This application has graphics designed by a professional graphic artist and looks far above any other example application that I've ever seen.
As soon as I saw that Mr. Zammetti had written a book, I rushed to be the first to volunteer to review it. This will need no explanation to members of the Struts mailing list, but for the rest of you it might help if I explain that he is that wonderful combination of a funny and helpful guy. I knew that anything he wrote was going to be first rate technically and was also going to be written in a light and relaxed style; always a winner in this kind of book.
I liked the fact that Mr. Zammetti covers a number of approaches to writing both the client and server-sides of the applications. For the server-side of a number of the applications, he uses plain JavaServer Pages, yet for others he uses industry-leading frameworks including WebWork and Struts. On the client-side he continues to mix it up, with some applications using "naked" Ajax, others using DWR, AjaxTags from Java Web Parts, DWR, Dojo, JSON and Prototype.
One more thing to like about the book is that the applications actually look very nice and quite professional. Perhaps the folks at 37signals shouldn't be nervous, but Mr. Zammetti has certainly raised the bar for the appearance of example applications for books.
The flip side of the use of multiple frameworks and Ajax libraries is that all of the breadth means reduced depth. Each of the frameworks and libraries is introduced and demonstrated, but then just as it begins to get interesting, it's off to the next one. If you're looking for more depth in each introduced item, then this book may not be for you.
In conclusion, this is a useful and practical book for those wishing to write web applications that combine Ajax front-ends with Java technology on the server-side. Strongly recommended.
You can purchase Practical Ajax Projects with Java Technology from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
If you plan to use lots of Ajax, it's probably better to build your own framework rather than using 3 different ones so that you have all the functionality you need. There really isn't all that much to AJAX, and it's not to hard to build your own framework to support all the features you need.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
Er, I like some of the results that people have made from AJAX, but to call it anything like the "ultimate client-side technology" is utterly bizarre and casts extreme doubt on the reviewer's credentials to review anything computer-related. I think it's safe to say that everyone that has studied AJAX has one overwhelming common opinion:
"For the LOVE OF GOD! Why the hell in the year 2006 do we need to write anything in this godawful buggy language? There HAS to be a better solution. THERE HAS TO BE! STFU, there HAS to be! Please, GOD, there must be!! [breaks down in tears]"
If AJAX is the "ultimate", then we might as well all take the poison kool-aid, because human civilization is an abject failure.
Sometimes it's best to just let stupid people be stupid.
I mean, it and its crew sure as hell couldn't stop Flash Gordon, and it did for the Emperor Ming. I for one don't want to be writing code only to be be speared by some giant spaceship coming through my back wall.
Who reads several books on a technology before they "try it out"?
Hah! Ultimate? Hardly.
AJAX is a hack to add more "dynamicallness" to web sites. HTML currently relies on HTTP and HTTP suffer a fatal flaw: it is client-initiated. Put another way: it's a poll technology. There is no way to allow the server to initiate a connection to a client.
As sites integrate more and more AJAX you tend to notice that what they are ultimately striving for is a standard desktop application. But it won't work as is and so AJAX is just a mere band aid. Ever try to use Google calender or gmail with a slow/latencied connection or when their servers are busy? I've had to wait over 30 seconds for an event to display in their calendar without any GUI notification that it's working. This can be mitigated but my point that such failures as a GUI are prevalent in AJAX applications because they're trying to be something they can't -- a desktop app.
I don't care how nifty AJAX makes web sites but don't call it "ultimate". Please.
No, the "ultimate" technology will not include HTML, HTTP, or JavaScript in their current incarnations as all have fatal flaws that just can't measure up to a standard desktop app in terms of functionality. This would be fine if the goal was different but it's not and it's precisely why (all things being a equal as possible) I will never bet on an online office suite trumping a true desktop app.
Nevermind that what web apps are heralded for -- cross-platformness -- requires a lot of effort to make happen. IE, FF, opera, and safari just don't act the same way in terms of rendering and JS functionality. There are so many things working against this AJAX movement that I'm amazed that it works (mostly).
:wq
What were you expecting it to do? Once you give the HTML to the browser, it attempts to parse it, add it to the DOM, and render it. It can't do that if you've still got open tags. So it assumes that you forgot to close your tag, and closes it. The exact same thing would happen if you accessed the DOM through Java, C/C++, or any other language.
This just goes to show the problems with the innerHTML psuedo-standard. People think that HTML consists of a bunch of strings, when it's actually a complete Object model that we are able to store serialized versions of. While innerHTML can be convenient for even the experts, it's going to do strange things if you don't understand what you're doing.
If you didn't understand a word of that, then I recommend that you visit your friendly standards organization and start reading. Until you understand exactly what you're doing, you are in an unfit state to program DHTML constructs. Trust me, you WILL regret it later if you don't get the basics down NOW.
Since someone else posted the proper DOM answer to your issue, here's the innerHTML answer:
Javascript + Nintendo DSi = DSiCade
If you're maxing out CPU, you have problems bigger than the use of ajax. Ajax usually results in using the same bandwidth differently. You make more server requests than a traditional app, but the requests exchange smaller amounts of data. It's possible to misuse any technology and blame the technology for your own incompetence. Sounds like you've achieved the latter.
You can make a difference. Donate to The LEEBY (Larry Ellison's Even Bigger Yacht) Fund.
I've just started cracking a few books on AJAX and I think this book avoided the libraries you mentioned for a couple of reasons.
*The book's goal is to teach you how AJAX actually works through coding JavaScript and JAVA in a sampleproject. GWT (I'm not real familiar with ECHO) very much abstracts what's going on at the browser level. In short, you could make AJAX apps with GWT, but you wouldn't really learn how AJAX apps function. For the purposes of illustratring how AJAX works, the libraries in something like Dojo work better.
*There is a surfeit of libraries and tools for AJAX. I've seen plenty of books that just catalog libraries; unfortunately, that broad coverage tends to keep you from using the technology in depth. If anything, until you start using one set of tools, you never really know what best suits your needs. It seems like it doesn't focus on just one toolkit anyway.
In short, the books gives you exposure to a few different libraries as you work through the projects so you can make a more informed choice later when looking at tools like GWT.
Mainframes worked the same way, and that didn't stop them any. In fact, it would be stupid to have a server trying to contact a bunch of firewalled client boxes out on the Internet. Besides not being scalable, the pull design of the web ensures that the clients are protected against exactly that sort of communication.
I think the issue you're concerned about is that there's no way to maintain an open channel. i.e. IRC maintains an open connection. Telnet maintains an open connection. FTP maintains an open connection. Pretty much everything except AJAX can maintain a connection rather than having to poll for the latest content at regular intervals.
I agree that such a design can be annoying, but it's something of a requirement for the web to function properly. Right now, you've got a few ways around this:
1. Use Mozilla APIs in a signed web application to obtain a low-level TCP/IP connection.
2. Find a Draft Web Application standards compliant browser, and use that so you can open a TCP/IP connection. (Good luck on that.)
3. Use the Livescript interface between Java and JavaScript to maintain a TCP/IP connection over a hidden applet.
4. Use an IFrame pointing to a servlet that keeps the connection open. Every time the server wants to tell you something, it "pushes" (i.e. writes and flushes) a few JavaScript commands down that pipeline. Those commands get executed immediately, thus providing a remote event system. The JavaScript code monitors the connection and automatically reconnects if the connection is lost. (This is what most web<->IRC portals do.)
5. Redesign your application. You're probably trying to do something that's a bad idea in the first place.
Javascript + Nintendo DSi = DSiCade
Does anybody else get the same feeling when working with the web? We have had incredible advances in technology yet we keep using HTML and JavaScript as our base for no other reason than tradition and because that is what people expect.
Stop it with these nonsense books and just pick up GWT. Understand that putting it all on the client side is more powerful and in practice generally more reliable and just as fast as server side tool kits, if not more so.
I believe this is the real benefit of AJAX methods that go beyond the asynchronous client/server communication.
Now you write Java programs that are compiled into complete Javascript programs that work on IE, FF, Safari and Opera with generated DHTML, etc. You use whatever you want back on the server side. The Javascript generated for you will probably be as good as anything you can write in JS and most likely more complex and better tested.
This is such a better parigdim than having the server create these user forms and controls using minimal Javascript and then posting back for more forms. Or simply sending all the forms over in a bloated DHTML mess. Now we have actual programs on the client side that behave like Websites and rich clients.
Make a site in GWT and see how easy and fun it is. It's a whole different world of Website and very clearly the future. Maybe not GWT, but having a Javascript program as the Website and the server agnostic. I would assume we will see better Javascript caching and a client/server versioning system to make sure users have the latest version of a site making for insanely fast Websites that are downloaded once with only calls for content and no longer infrastructure.
"If you are a dreamer, a wisher, a liar, A hope-er, a pray-er, a magic bean buyer
Mainly because GWT and Echo are way too advanced for a book such as this.
Why just tell people they could use these amazing toolkit paragdims when you can sell them a book explaining how the pipes run?
GWT and Echo and related technologies are really great. I like GWT more because of it putting everything client related on the client side. I see this as the future of Web programming and we will see more and better tools to facilitate this. One being better program caching with checksums and client/server versioning to allow for download once, run every time Websites in the EOC (Everything On Client) model.
"If you are a dreamer, a wisher, a liar, A hope-er, a pray-er, a magic bean buyer
Everyone is out rushing to build AJAX apps into even the simplest applications, and the result is slow loading time and greatly increased server loads.
While this no doubt happens all the time, the main advantage of AJAX-enabled web applications is reduced load on the server. For instance, our intranet application uses the Tapestry framework, and the built-in tables component (at least for the 4.0 version) was useless because it required constant, complete page refreshing when all you really wanted to update was the contents of a table. We rolled our own table component that's fully ajaxificated and it's been nothing but positive for our end users and our servers.
Writing code that uses more network bandwidth than you've got is not an AJAX problem. It's a "writing code that uses more network bandwidth than you've got" problem. One could achieve the same thing in Java. That doesn't make it a Java problem.
Attention zealots and haters: 00100 00100
On the topic of Java and Ajax you should check out icefaces, its a great Ajax framework and its completely free, and does not require any javascript programming.
Check out their Component Showcase.
Ajax only breaks the back button when it us use for a site's navigation.
This is just as bad as when someone develops a site entirely in flash.
Sure the technology can be misused, but the fact that some people misuse it, doesn't make it a bad technology.
"If they have both, tell them we use Linux. And if they have that, tell them the computers are down." -Dave Chapelle
Anyone else sick and tired of all this Ajax hype? I wonder how much damage is all this hype causing. Just a while ago my boss asked me to implement a simple one single text field and button form with Ajax because he wanted to make sure the submission was "responsive". After trying to persuade him otherwise and failing, it is needless to say, a simple project became a mess very quickly with very little benefit for the end user. Ajax has its place and usage, I think that's what these books should be focusing on rather than selling it as holy water.
[alk]
I recently released my version of web-based Risk, called Grand Strategy. It is an Ajax application written using DWR (Direct Web Remoting) and the Dojo Toolkit.
It is by far the most sophisticated Ajax base game I have seen. I'd be interested in comparing it so other Ajax based games.
Has anyone seen or developed an Ajax based game I could take a look at?
Grand Strategy
AJAX is not some magical voodoo that is somehow uniquely capable of bringing down a web server. All it is is a means for doing an HTTP request, just like for a web page, in the background, without re-requesting and re-rendering the whole page. That's it. Just HTTP requests to a web server.
If you want to use it to make a web page that hits the server on every mouse click, you can. That's your business. But you could also code it up the traditional, non-AJAX way, to also hit the web server on every mouse click. AJAX is no more the problem than submitting forms is.
I must say, our existing CGI-based solution worked far better.
That's not an alternative to AJAX. I'm building an AJAX app that is serviced via CGI. CGI is just a way to respond to a web request. Whether a form post, a get request, or an AJAX request. It sounds like you don't really know what you're talking about.
Attention zealots and haters: 00100 00100