GWT in Practice

377 Pages·2008·10.8 MB·English

by  Robert Cooper

GWT in Practice

GWT in Practice
ROBERT COOPER
CHARLES COLLINS
MANNING
Greenwich
(74° w. long.)
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ISBN 1-933988-29-0
Printed in the United States of America
1 2 3 4 5 6 7 8 9 10 – VHG – 12 11 10 09 08
contents
preface xi
acknowledgments xii
about this book xiii
about the cover illustration xvii
PART 1 GETTING STARTED..............................................1
1 Introducing GWT 3
1.1 Why GWT 5
History 5 ■ Why Ajax matters 6 ■ Leveraging the web 7
Tooling and testing 7 ■ A single code base 8 ■ Limitations 8
1.2 What GWT includes 9
GWT compiler 9 ■ User Interface layer 10 ■ Remote Procedure
Calls 10 ■ Additional utilities 11 ■ GWT shell 12
1.3 GWT basics 13
Modules and inheritance 13 ■ Host pages 14
Entry point classes 16
1.4 Working with the GWT shell 16
The logging console 17 ■ The hosted mode browser 18
v
vi CONTENTS
1.5 Understanding the GWT compiler 19
JavaScript output style 20 ■ Additional compiler nuances 23
The compiler lifecycle 24
1.6 Summary 30
2 A New Kind of Client 32
2.1 Basic project structure and components 33
Generating a project 34 ■ The standard directory structure 35
GWT starting point files 36 ■ Host pages 37 ■ Modules 38
Entry points 40
2.2 Design patterns and GWT 40
MVC and GWT 41 ■ Creating a widget 42 ■ Communicating
by observing events 46 ■ Operator strategy 48 ■ Controlling
the action 51
2.3 Styling a GWT component 54
Providing a CSS file 54 ■ Connecting style names with Java 56
2.4 Running a completed project 56
Hosted mode and the GWT shell 57 ■ Web mode and the
GWT compiler 58
2.5 Summary 59
3 Communicating with the Server 61
3.1 Making GWT Remote Procedure Calls 62
Starting the HelloServer project 62 ■ Defining GWT
serializable data 64 ■ Creating RPC services 66
Expanding on RemoteServiceServlet 69 ■ Calling the server
from the client 70 ■ Troubleshooting server communication 74
3.2 The development server—Tomcat Lite 75
The web.xml file 75 ■ The context.xml file 77
3.3 Using an external development server 79
3.4 Summary 80
PART 2 TASK-SPECIFIC ISSUES........................................83
4 Core Application Structure 85
4.1 Building a model 86
CONTENTS vii
4.2 Building view components 90
Extending widgets 90 ■ Extending composite 93
Binding to the model with events 95
4.3 The controller and service 98
Creating a simple controller 99 ■ JPA-enabling the model 100
Creating a JPA-enabled service 104
4.4 Summary 106
5 Other Techniques for Talking to Servers 107
5.1 Web development methods and security 108
Dealing with browser security 108 ■ Understanding
XMLHttpRequest 110 ■ Coding asynchronously 110
Developing GWT applications in NetBeans 111
5.2 Enabling REST and POX communications 112
Making basic HTTP requests with GWT 112 ■ Making
advanced HTTP requests with GWT 114 ■ Working
with XML 115
5.3 Understanding Java-to-JavaScript interaction 116
Using GWT JavaDoc annotations to serialize collections 116
Using JSON 119
5.4 Creating a cross-domain SOAP client with Flash 121
Using Flash as a SOAP client 121 ■ Setting a Flash
security context 130 ■ Drawbacks and caveats 131
5.5 Incorporating applets with GWT 131
Using Java as a SOAP client 131 ■ Signing JARs
for security bypass 136
5.6 Streaming to the browser with Comet 137
5.7 Summary 147
6 Integrating Legacy and Third-Party Ajax Libraries 148
6.1 A closer look at JSNI 149
JSNI basics revisited 149 ■ Potential JSNI pitfalls 151
Configuring IntelliJ IDEA 153
6.2 Wrapping JavaScript libraries 155
Creating a JavaScript module 156 ■ Creating
wrapper classes 156 ■ Using the wrapped
packages 159
viii CONTENTS
6.3 Managing GWT-JavaScript interaction 162
Maintaining lookups 162 ■ Daisy-chaining Java listeners
into JavaScript closures 166 ■ Maintaining listeners
in Java 168 ■ Conversion between Java and JavaScript 172
6.4 Wrapping JavaScript with GWT-API-Interop 178
6.5 Summary 181
7 Building, Packaging, and Deploying 183
7.1 Packaging GWT modules 184
Building and packaging modules 184 ■ Sharing modules 186
7.2 Building and deploying applications 187
The client side 188 ■ The server side 188 ■ Manually building
a WAR file 189
7.3 Automating the build 191
Extending the Ant build 191 ■ Using Maven 195
7.4 Managing Tomcat Lite from the build 205
7.5 Summary 210
8 Testing and Continuous Integration 211
8.1 GWT testing 212
Knowing what to test 212 ■ How GWT testing works 213
Testing gotchas 214 ■ Basic GWT tests 217 ■ Testing
outside of GWT 224
8.2 Advanced testing concepts 226
Benchmarking 227 ■ Remote testing 229
Code coverage 231 ■ Coverage in an automated build 234
8.3 Continuous integration 239
Adding a GWT project to Hudson 240
8.4 Summary 245
PART 3 FULLY FORMED APPLICATIONS.........................247
9 Java Enterprise Reinvented 249
9.1 Constructing two models 251
9.2 Mapping to DTOs 257
9.3 Wiring applications with Spring 260
CONTENTS ix
9.4 Constructing the client application 265
The controller and global model 266 ■ The basic
CRUD wrapper 269 ■ The BookEdit widget 272
9.5 Summary 279
10 Building the Storefront 281
10.1 Securing GWT applications 282
10.2 Building a drag-and-drop system 289
Enabling dragging 290 ■ Handling drops 293
10.3 JSNI special effects 296
10.4 Summary 299
11 Managing Application State 300
11.1 Overview of the sample application 301
11.2 Creating a basic messaging service 304
11.3 Handling messages on the client and server 310
Messages and CometEvents 310 ■ Streaming messages
to the client 312 ■ Receiving images 315
11.4 Recording and playing back conversations 317
Capturing changes to the model layer 320 ■ Handling deep
links 325 ■ When to use hyperlinks rather than history 326
11.5 Dealing with state on the server side 327
11.6 Adding a UI and cleaning up 330
Displaying events 330 ■ Sending events 331
Cleaning up 333
11.7 Summary 334
appendix A Notable GWT Projects 335
appendix B Quick Reference 338
index 351