Features and Benefits
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A complete and in-depth introduction to building applications with the Google Web Toolkit (GWT)
* Author is one of the first adopters of GWT and one of the most active members of the GWT Google Group community
* Unlike competition, book is up-to-date with the latest version of GWT released in August 2007
* Second half is comprised with complete application examples, making this a true 'learn by doing' guide
* Book is supported and endorsed by the creators of GWT
Table of Contents
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Preface xvii
About the Author xxiii
Part I: Understanding the Google Web Toolkit 1
Chapter 1: First Steps with the Google Web Toolkit 3
The Emergence of Ajax 3
Rethinking Web Applications 5
Software Engineering for Ajax 8
Evaluating Your Background 11
The Importance of Application Development Skills 14
A Quick Tutorial 16
Overview of Toolkit Packages 30
Overview of GWT Applications 34
Summary 36
Chapter 2: User Interface Library Overview 37
Static Widgets 38
Form Widgets 47
Complex Widgets 63
Simple Layout Panels 70
Complex Layout Panels 80
Simple Container Panels 84
Complex Container Panels 87
User Interface Framework Glue 95
Summary 103
Chapter 3: Server Integration Techniques 105
Basic Server Integration Techniques 105
Using Data Format Libraries 117
Third-Party Server Integration 125
Advanced Server Integration Techniques 128
Summary 137
Chapter 4: Software Engineering for Ajax 139
Setting Up the Development Environment 139
Adding Projects to Eclipse 145
Writing Java Code in Eclipse 149
Debugging in Eclipse 158
Organizing Your Application Structure 164
Testing Applications 168
Building and Sharing Modules 180
Deploying Applications 183
Summary 190
Chapter 5: Using the Toolkit Effectively 191
Using Asynchronous Programming 191
Handling the Back Button 197
Creating Elegant Interfaces with CSS 200
Extending the Toolkit 212
Internationalizing Applications 226
Generating Code 235
Improving Performance 242
Summary 251
Part II: Rich Web Applications by Example 253
Chapter 6: Gadget Desktop Application 255
Using the Container Application Pattern 256
Designing the Model 257
Building a Columned Container Interface 264
Putting Gadgets in the View 274
Creating Drag-and-Drop Gadgets 283
Cleaning Up User Interfaces with CSS 290
Adding Persistency 300
Using Other JavaScript Libraries 309
Summary 318
Chapter 7: Multi-Search Application 319
Using the Aggregator Application Pattern 319
Multi-Search Design 321
The Model 322
The View 324
The Controller 331
Importing Structured Data Formats 334
Integrating with Yahoo! Search 340
Integrating with Google Base 344
Integrating with Flickr Search 348
Integrating with Amazon Search 354
Summary 358
Chapter 8: Blog Editor Application 361
Using the Workspace Application Pattern 361
Building a Web Service Client 363
Blog Editor Design 365
The Model 365
Building a Multiple Document View 367
Adding Rich Text Editing 381
The LoadingPanel Widget 386
The TitleCommandBar Widget 388
Designing the Application Controller 390
Building an HTTP Proxy Servlet 392
Integrating with the Blogger API 401
Summary 421
Chapter 9: Instant Messenger Application 423
Using the Collaborator Application Pattern 423
Instant Messenger Design 425
The Model 426
Building a Complementary Interface 429
The Controller Overview 447
Using GWT-RPC 450
Connecting to the Server 456
Adding RPC Events 458
The Instant Messenger Server 465
Using Server-Side Advanced IO 470
Summary 478
Chapter 10: Database Editor Application 479
Using the Manager Application Pattern 480
Designing the Model 482
Using Asynchronous Data Access Objects 485
Building a Two-Paned Editor Interface 488
Server Integration Overview 507
Writing a Generic GWT Code Generator 510
Integrating with Action-Based PHP Scripts 522
Integrating with a RESTful Ruby on Rails Application 530
Integrating with a GWT-RPC Servlet 542
Summary 554
Index 555
Preface
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I've always had an interest in the nontechnical side of software development: the user experience. It started back when I was working on teams building the core of application servers in C++. We admired the beauty of the C++ language and its expressiveness. We made large, complex systems run seamlessly with elegant code. We marveled at our templating techniques, which made the C++ compiler churn out code just like a code generator would. Then I would leave work and was not able to mention a word of it without receiving blank stares in return.
I decided to find time to write a client-side application that would be as elegant to the user as well-written code can be for a developer. I chose to build an instant messenger application, mostly with C++, that combined the four major networks into one interface. At the time, instant messengers were becoming bloated with features-there were too many buttons distracting users from sending a simple text message. The instant messenger application I developed resulted in a much better user experience for instant messaging: instead of users downloading a 10MB application with a five-step installation process, I optimized the messenger to be 200K with a clean interface (much like the Google Talk messenger is today). As a result, it was downloaded over a million times.
While developing interfaces in C++ I was always impressed by the ease of creating a nice-looking interface on a web page. If you compare the code required to set a font in C++ to cascading style sheets, you'll see what I mean. Then Ajax started to become popular, producing web interface behavior similar to desktop interface behavior. Combine this with the ease of making things look better with CSS, and you have a much better platform for interface development.
I was really impressed when I saw Google Maps for the first time. The user experience was perfect. I simply typed maps.google.com into my browser and I was instantly provided with a fully functional map application. I could drag the map around in different directions, traveling around the world, zooming in and out without waiting for a page referesh. I had a brief look at the technology needed to do this, specifically JavaScript, and was disapointed. I knew there were limits to what you can build with JavaScript. It would be nearly impossible to build large complex client-side applications with it.
Then the Google Web Toolkit (GWT) was released, and I decided to try writing an application using it. In only three weeks I had built the client and server side for a poker application. I put it up at http://gpokr.com. You could simply type the URL into your browser and be instantly presented with a live poker game. No downloads, no installations, and the interface could be styled nicely and easily with CSS. Scott Blum, Bruce Johnson, and Joel Webber from the GWT team came by to do some "testing," and I had the opportunity to thank them for building an incredible tool. I marveled at being able to write elegant Java code that could be transformed into JavaScript by the GWT compiler. I was really impressed by how GWT so solidly let anyone create applications that delivered great user experiences.
After GWT's initial release, I found that its great abilities weren't clear to many and that it would take a book with several real examples to illustrate this. I had never written a book before, and to write one on a technology that was not my specialty didn't seem quite right. But then again, nobody specialized in GWT at this point. I believed enough in the technology to give it a shot. To make up for my lack of experience and before writing any of the chapters, I spent several months exclusively developing GWT applications to explore every part of GWT as well as every part of web technology that GWT could touch. Part II of this book presents five of these applications.
What Is This Book About?
This book is about writing nontrivial Ajax applications to create great user experiences using web technologies and Java development tools, with GWT bridging the two. The book focuses primarily on the Google Web Toolkit, with an in-depth look at its library and tools. As a secondary focus, it covers software development techniques and patterns using Java, and how to apply Ajax application development with GWT. A terciary focus is on web technologies, including web standards and other Ajax libraries and APIs.
Who Should Read This Book?
I'm a developer who wrote this book for other developers. Software developers who need to create user-facing applications should read this book. Most of the code in the book is based on Java, but care is taken so that the book is accessible to a beginner with the language. If you don't know Java, you should familiarize yourself with the language before starting this book. Sun has great tutorials to get you started: http://java.sun.com/docs/books/tutorial/java/index.html.
GWT is not just an Ajax tool for Java developers. I think this view severely undercuts its true strength. Java developers will find using it easy; however, the technology is for any software developer who needs to build nontrivial Ajax applications. You could be a .NET, PHP, Ruby, or C++ developer. If you're one of these developers you would need to learn another language to build an Ajax application whether you use GWT or not. I recommend that you learn Java-starting with the previously mentioned tutorials from Sun, and GWT through this book and the GWT documentation at http://code.google.com/webtoolkit/documentation/-instead of JavaScript. As a result, you will save a substantial amount of time debugging and maintaining the application while creating a much better user experience.
Organization of This Book
This book has two parts. Part I gives you an in-depth introduction to using the Google Web Toolkit. You can use it as a reference for the GWT library or as a guide to using effective development techniques with GWT. Part II provides a thorough look at five nontrivial applications built with GWT. In this part you'll find development patterns, techniques, and subtleties used through application design and development. Each application in this part is designed to be a balance of GWT library usage, web service and technology interoperation, application design and architecture, and user interface design. As you read through these chapters, you can follow along and construct the applications on your machine. The chapters include most of the code, but you'll need to refer to the source code at www.gwtapps.com in certain instances that are identified.
Part I: Understanding the Google Web Toolkit
* Chapter 1, First Steps with the Google Web Toolkit, introduces web technologies, skill sets, and GWT, and includes a short tutorial on creating an Ajax game application.
* Chapter 2, User Interface Library Overview, details the user interface library that comes with GWT. This material consists mainly of notes and examples based on the usage of each widget.
* Chapter 3, Server Integration Techniques, describes several methods for integrating with server-side applications.
* Chapter 4, Software Engineering for Ajax, looks at Java tools for software development and how they apply to GWT development.
* Chapter 5, Using the Toolkit Effectively, covers some of the more advanced techniques of development with GWT, including CSS, code generation, internationalization, and performance.
Part II: Rich Web Applications by Example
* Chapter 6, Gadget Desktop Application, presents a gadget application with a rich drag-and-drop interface, persistence with cookies and Gears, along with using JavaScript APIs with GWT.
* Chapter 7, Multi-Search Application, shows how to create a search application that makes requests to many search engines. The application uses JavaScript Object Notation with Padding (JSONP) to communicate with Google, Yahoo!, Amazon, and Flickr.
* Chapter 8, Blog Editor Application, walks you through an application to manage blog entries across many blogs. This application integrates with the Blogger REST API using an HTTP proxy.
* Chapter 9, Instant Messenger Application, details a web page instant messenger based on GWT-RPC. It covers how to use an event-based protocol along with optimizing with Comet on Tomcat and Continuations on Jetty.
* Chapter 10, Database Editor Application, looks at a database manager for a traditional web page. The application explores advanced topics such as reading complex data structures from the server using Data Access Objects, code generation for easy XML and JSON, and integrating with PHP, Ruby on Rails, and Java with Hibernate.
Web Support
The web site for this book is located at www.gwtapps.com. It contains the source code and live demos for the sample applications, a forum for questions and error reports, and other useful reference material.
About the Authors
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Ryan Dewsbury is a developer, architect, and consultant who started working in C++ and Java in 1998 and has used GWT since its first release. His recent projects include developing software applications with GWT (most notably gpokr.com and kdice.com). As a consultant, Ryan helps companies develop great online user experiences using cutting-edge software.
