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GWT in Action
Michael J. Ross writes "Server-side computer languages, such as Java, possess numerous advantages over their client-side counterparts — including more robust integrated development environments (IDEs). In contrast, Web-focused languages, such as JavaScript, benefit from the global accessibility of the Internet. Bridging this gap, and leveraging the strengths of both sides, has long been an objective of the software development community — though not all attempts have been successful, e.g., Java applets. The Google Web Toolkit (GWT) is the latest attempt, and shows considerable promise, as illustrated in a new book intended to help programmers learn this new technology: GWT in Action." Read on for the rest of Michael's review
GWT in Action
author
Robert Hanson and Adam Tacy
pages
600
publisher
Manning Publications
rating
6
reviewer
Michael J. Ross
ISBN
1933988231
summary
A practical introduction to programming with the Google Web Toolkit (GWT).
Written by Robert Hanson and Adam Tacy, this book was published by Manning Publications on 5 June 2007, under the ISBNs 1933988231 and 978-1933988238. For any prospective reader who would like to learn more about the book, they can first try the book's Web page, where they will find online versions of the "about this book" section, table of contents, preface, and index. The publisher offers two freely downloadable chapters, "Creating the Default Application" and "Communicating with GWT-RPC," in PDF format. In addition, there is a link to purchase the book's electronic version, and a link to the author's forum, where readers can post questions about the book or GWT, and likely receive a response — perhaps even by one of the authors.
The book's 17 chapters are organized into four parts, and cover a generous number of topics: introduction to GWT; creating the default GWT application; building your own application based upon the default one; creating widgets and panels, including composite panels; processing user events; creating JSNI components; modularizing your code; communicating using GWT-RPC; client-side RPC; classic Ajax and HTML forms; using JSON for interoperability; automatically generating code; GWT's native properties; testing and deploying GWT applications; more on the inner workings of GWT itself. The book has no appendices, but a substantial index, which is essential for such a technically detailed subject area.
GWT in Action is clearly intended to be a practical and fairly comprehensive coverage of Google's new toolkit. Almost all of the GWT concepts are explained within the context of developing a substantial sample application, the Dashboard, created by the authors. The reader is encouraged to follow along as the authors build the application, thereby learning from doing — almost always an effective approach. At 600 pages, with almost none of the formatting padding found in far too many technical books nowadays, the authors have not skimped on providing the reader with a lot of information. Furthermore, their treatment of application deployment is far better than any other I have encountered.
Unfortunately, the book has many weaknesses. On an overall basis, the order of presentation is at times disjointed — seemingly dictated more by the Dashboard and less by the most logical order for someone new to GWT. Compounding the problem, the authors frequently refer to advanced topics, covered in greater detail later, and also repeat earlier information, occasionally several times. Despite promises to provide a gentle exposition, it can be difficult at times for the reader to determine if any critical steps were skipped, as a consequence of key instructions for building the sample application being spread out, and interspersed with too many references to general comments covered earlier. In turn, readers will likely find it frustrating to try to get the sample application working at each step of the development process — and not just at the end, with the complete code.
One source of these difficulties, is that in the first few chapters, the authors try to introduce too many topics all at once, and as a result do not thoroughly discuss each one in its own section. Instead, they break up the information over multiple sections, scattered throughout the book. An example of this is internationalization. Section 2.2.4 is titled "Implementing Internationalization," and yet provides almost no details, and is essentially unusable by itself. At the very least, it should mention that later sections 3.2.1 and 15.3 provide a lot more information. Furthermore, internationalization was introduced far too early in the book, and greatly complicates the process. Instead, the authors should have created a simple application using only English for the user interface, and introduce internationalization later, after fully explaining the basics of turning Java code into JavaScript functionality.
Part I of the book is the weakest of all of them, which may, sadly, turn off readers who would otherwise get to the better material later. The authors are clearly enthusiastic about the topics at hand, and the number of moving parts associated with Java/JavaScript/GWT development is certainly not trivial. Nonetheless, those initial chapters would greatly benefit from a rewrite; this would make the material more comprehensible and easier to follow, step-by-step.
We can mention some specific flaws: A book like this that is introducing a new technology, must take care to not leave the unwarned reader wondering if they have been left behind in the steps. People reading some of the earlier material may conclude that those steps have already been assumed by the authors, and will not be covered. The authors do not mention how to obtain and install GWT until page 30; that should be right up front. The authors do not appear to mention which version of GWT they used for the book. (I chose 1.3, not 1.4RC, available as of this writing). Any reader trying to follow along and implement their example application (the Dashboard) will probably find several hurdles. First of all, make sure that you have version 1.4 of GWT installed, and not 1.3.3, which does not include some of the panels and widgets used in their sample code.
In Chapter 1, they modify a "Hello world" application to create another application that shows a tic-tac-toe board that has clickable squares, but does not play the game. Chapter 2 describes this as "a fully functioning Tic-Tac-Toe application," which is like claiming a program works because it compiles. Also in Chapter 2, their discussion of development alternatives is slowed down by repetition of the same information. The sample code in the book has minor inconsistencies. For example, naming a password String "oldPass" in one method, then "old" in another, related method. There are other instances, but these give one an idea of some of the inconsistencies.
The coverage of topics is generally quite thorough, though at times verbose and redundant — particularly in Chapter 2, though it is certainly not limited to that chapter. The second and third paragraphs in Chapter 3, for instance, continue the repetitious style which is found in many places throughout the book, and likely has made it longer than necessary. In Chapter 4, the first two pages explain what widgets are, several times, and conclude with a picture of a button — as if any reader who has made it that far into the book doesn't know what a button is. The book could certainly use some trimming.
The downloadable source code is not complete. For starters, it is missing the code from Chapters 1 and 2, though admittedly none of that is too long. The code provided for Chapter 4 is just a portion of what is displayed in the book. Moreover, the directory paths in the sample code archive files, are not consistently named, and some may even be incorrect. For example, the code for Chapter 5 has a folder named "Dashboard — Chapter 4." That sort of thing does not instill confidence in the typical reader. The authors should revisit the sample code — making it complete and consistently named.
The publisher's page for the book does not appear to have a link for errata; perhaps none have been reported yet. Here are some: On page 75, in Table 3.1, in the left-hand column, "gwt-onLoadErrorFn" should instead read ""gwt:onLoadErrorFn." On page 77, in the second paragraph, the file name extension should be all lowercase, not all uppercase. On page 78, in Listing 3.6, the String parameter in the first label.setText() call should be delimited with straight quotes, not curly quotes. (Microsoft Word strikes again?!) On page 81, in the third paragraph, "comply to" should read "comply with." On pages 87 and 88, the -whitelist and -blacklist option values each contain an extraneous space before the "^." There are undoubtedly more such errata throughout the book, and can be corrected in the next edition; but these are enough to at least get an errata file started. Fortunately, none of them would lead an alert reader astray.
Even though the book could use significant reorganization and streamlining in the next edition, GWT in Action is packed with practical information on a wide range of GWT topics.
Michael J. Ross is a Web developer, freelance writer, and the editor of PristinePlanet.com's free newsletter.
You can purchase GWT in Action from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
The book's 17 chapters are organized into four parts, and cover a generous number of topics: introduction to GWT; creating the default GWT application; building your own application based upon the default one; creating widgets and panels, including composite panels; processing user events; creating JSNI components; modularizing your code; communicating using GWT-RPC; client-side RPC; classic Ajax and HTML forms; using JSON for interoperability; automatically generating code; GWT's native properties; testing and deploying GWT applications; more on the inner workings of GWT itself. The book has no appendices, but a substantial index, which is essential for such a technically detailed subject area.
GWT in Action is clearly intended to be a practical and fairly comprehensive coverage of Google's new toolkit. Almost all of the GWT concepts are explained within the context of developing a substantial sample application, the Dashboard, created by the authors. The reader is encouraged to follow along as the authors build the application, thereby learning from doing — almost always an effective approach. At 600 pages, with almost none of the formatting padding found in far too many technical books nowadays, the authors have not skimped on providing the reader with a lot of information. Furthermore, their treatment of application deployment is far better than any other I have encountered.
Unfortunately, the book has many weaknesses. On an overall basis, the order of presentation is at times disjointed — seemingly dictated more by the Dashboard and less by the most logical order for someone new to GWT. Compounding the problem, the authors frequently refer to advanced topics, covered in greater detail later, and also repeat earlier information, occasionally several times. Despite promises to provide a gentle exposition, it can be difficult at times for the reader to determine if any critical steps were skipped, as a consequence of key instructions for building the sample application being spread out, and interspersed with too many references to general comments covered earlier. In turn, readers will likely find it frustrating to try to get the sample application working at each step of the development process — and not just at the end, with the complete code.
One source of these difficulties, is that in the first few chapters, the authors try to introduce too many topics all at once, and as a result do not thoroughly discuss each one in its own section. Instead, they break up the information over multiple sections, scattered throughout the book. An example of this is internationalization. Section 2.2.4 is titled "Implementing Internationalization," and yet provides almost no details, and is essentially unusable by itself. At the very least, it should mention that later sections 3.2.1 and 15.3 provide a lot more information. Furthermore, internationalization was introduced far too early in the book, and greatly complicates the process. Instead, the authors should have created a simple application using only English for the user interface, and introduce internationalization later, after fully explaining the basics of turning Java code into JavaScript functionality.
Part I of the book is the weakest of all of them, which may, sadly, turn off readers who would otherwise get to the better material later. The authors are clearly enthusiastic about the topics at hand, and the number of moving parts associated with Java/JavaScript/GWT development is certainly not trivial. Nonetheless, those initial chapters would greatly benefit from a rewrite; this would make the material more comprehensible and easier to follow, step-by-step.
We can mention some specific flaws: A book like this that is introducing a new technology, must take care to not leave the unwarned reader wondering if they have been left behind in the steps. People reading some of the earlier material may conclude that those steps have already been assumed by the authors, and will not be covered. The authors do not mention how to obtain and install GWT until page 30; that should be right up front. The authors do not appear to mention which version of GWT they used for the book. (I chose 1.3, not 1.4RC, available as of this writing). Any reader trying to follow along and implement their example application (the Dashboard) will probably find several hurdles. First of all, make sure that you have version 1.4 of GWT installed, and not 1.3.3, which does not include some of the panels and widgets used in their sample code.
In Chapter 1, they modify a "Hello world" application to create another application that shows a tic-tac-toe board that has clickable squares, but does not play the game. Chapter 2 describes this as "a fully functioning Tic-Tac-Toe application," which is like claiming a program works because it compiles. Also in Chapter 2, their discussion of development alternatives is slowed down by repetition of the same information. The sample code in the book has minor inconsistencies. For example, naming a password String "oldPass" in one method, then "old" in another, related method. There are other instances, but these give one an idea of some of the inconsistencies.
The coverage of topics is generally quite thorough, though at times verbose and redundant — particularly in Chapter 2, though it is certainly not limited to that chapter. The second and third paragraphs in Chapter 3, for instance, continue the repetitious style which is found in many places throughout the book, and likely has made it longer than necessary. In Chapter 4, the first two pages explain what widgets are, several times, and conclude with a picture of a button — as if any reader who has made it that far into the book doesn't know what a button is. The book could certainly use some trimming.
The downloadable source code is not complete. For starters, it is missing the code from Chapters 1 and 2, though admittedly none of that is too long. The code provided for Chapter 4 is just a portion of what is displayed in the book. Moreover, the directory paths in the sample code archive files, are not consistently named, and some may even be incorrect. For example, the code for Chapter 5 has a folder named "Dashboard — Chapter 4." That sort of thing does not instill confidence in the typical reader. The authors should revisit the sample code — making it complete and consistently named.
The publisher's page for the book does not appear to have a link for errata; perhaps none have been reported yet. Here are some: On page 75, in Table 3.1, in the left-hand column, "gwt-onLoadErrorFn" should instead read ""gwt:onLoadErrorFn." On page 77, in the second paragraph, the file name extension should be all lowercase, not all uppercase. On page 78, in Listing 3.6, the String parameter in the first label.setText() call should be delimited with straight quotes, not curly quotes. (Microsoft Word strikes again?!) On page 81, in the third paragraph, "comply to" should read "comply with." On pages 87 and 88, the -whitelist and -blacklist option values each contain an extraneous space before the "^." There are undoubtedly more such errata throughout the book, and can be corrected in the next edition; but these are enough to at least get an errata file started. Fortunately, none of them would lead an alert reader astray.
Even though the book could use significant reorganization and streamlining in the next edition, GWT in Action is packed with practical information on a wide range of GWT topics.
Michael J. Ross is a Web developer, freelance writer, and the editor of PristinePlanet.com's free newsletter.
You can purchase GWT in Action from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
He seems to be saying that overall it's a good book :D
Is it just me or is anyone else glad to see a review on Slashdot without a chapter by chapter summary? One of the most pointless, pedantic mistakes in book reviews is to summarize each chapter. Hoozah for the writer!
Depends on your engine. I've put some thought into the same sort of server-side Javascript engine as you have. Someone else mentioned the Netscape Enterprise Server. That was... not so great. I was thinking more along the lines of building on top of a Java Servlet Engine. The Mozilla Rhino Javascript Engine actually compiles the JS down to Java byte code. That wouldn't be all that special, except that the JVM then JITs that to native code. Which means that Javascript doesn't have to be slow.
I figure you could create a JSHttpServlet object and map a file of your own extension (it can be *.js if you want it to be) to that servlet. The servlet then creates a JS environment that maps HttpRequest and HttpResponse as global variables. You can even map HttpSession and a PrintWriter output stream if you want. (That gets pretty close to JSP territory.
Javascript + Nintendo DSi = DSiCade
Yeah?
I did an evaluation of it. I kind of liked it, but in general don't like "lets make a servlet environment pretend its an applet", so I didn't endorse.
Now, after months of using Wicket, I wish I had pimped for it more. Seriously. If you're gonna pretend it's an applet, then REALLY do it like GWT does, fake JVM and all. This Wicket stuff.... ugh. keeping the html view and java in synch for anythign complex is SO IRRITATING.
Seriously, after years of Struts and stuff like Wicket, I don't see any real advantage over "Model 2+" (Servlet/JSP pairs) that I started with in 2001. There is a benefit to simplicity and writing HTML in HTML and writing Javascript in Javascript that over-engineers who are, frankly, a little OO-obsessed just don't get.
Maybe years of Perl CGI has bent my brain but The HTTP Request/Response paradigm just doesn't seem so awful that it needs to be (leaky) abstracted away.
SO YOU'RE GOING TO DIE: The Comic for Dealing with Death
GUI stuff happens in Javascript. Anything really complicated gets sent over to Java. That's why it's called an AJAX framework, not a Javascript framework.
I like Javascript, but it has the same problem as PHP: no namespaces. Using it as a real language would causes the same problems you see there: security issues, hard-to-read code, difficulty refactoring, interoperability problems, etc. You can actually see those problems and the various mechanisms to overcome them in a lot of the modern pure-javascript libraries (prototype especially is known for breaking existing javascript libraries, for example).
Mod me down and I will become more powerful than you can possibly imagine!
Some day, I'll be able to use a browser to write desktop apps without resorting to plugins or XUL or whatever. No, Google Gears doesn't do that.
JS is a great language and GWT is a great tool, especially the hosted development environment. But it will never reach its potential until it is a general purpose application programming language.
"The first thing I'd like are some of my favorite features from Common Lisp, like first class functions, ability to do procedural, functional, and object oriented programming with the same language, dynamic typing, macros, closures, and lexical scoping.
Having a C-like syntax would be good for people who are used to C or Perl and don't want to learn about s-expressions. Automatic memory management is a must."
You just described pike (although it has both static and dynamic typing).
http://pike.ida.liu.se/
Just a few hours ago I finished a small, mostly-for-fun project in GWT, and now I see a GWT-related story on slashdot. Surely it's not a coincidence and therefore I must pimp my project: a chess board diagram composer.
David --
Maybe take another look at it. The learning curve is pretty minimal if you a) know java and b) have exposure to any other windowing toolkit, ala tcl/tk, swt, swing, etc. Couple hours tops, honestly. Secondly, the obfustication tech. makes the resulting javascript much smaller than hand-coded javascript, much the same way that a C compiler can write more efficient assembly than you or I could. Finally, I actually found the opposite about app size when I have used it with my customers -- for small apps it is perfect because you can produce a really slick interface very quickly. If you app has a lot of distinct functionality, and maybe parts of it aren't yet ported to GWT (for example) GWT actually gets in your way.
One of the most important points for using something like GWT has been missed: You can write test code for GWT very easily! If you ever tried to debug a mid-sized Javascript application, you know what I'm talking about. With GWT you have a hosted environment that makes debugging much easier. Also, you can employ Test Driven Development much easier. There is even explicit support for JUnit in GWT. For your favourite toy web application, GWT may be overpowered. For massive, distributed internet applications who need to involve the client side as much as they can, GWT currently is the best solution for Java shops.