Pro Wicket

328 Pages·2006·7.06 MB·English

CYAN YELLOW
MAGENTA BLACK
PANTONE 123 CV
EMPOWERING PRODUCTIVITY FOR THE JAVA™ DEVELOPER THE EXPERT’S VOICE® IN JAVA™ TECHNOLOGY
Companion
eBook Available
IInncclluuddeess
Pro Wicket
SSpprriinngg aanndd AAjjaaxx
P
Dear Reader,
Welcome to Wicket, an open source, lightweight, component- or POJOs-based r
Java™web framework that brings the Java Swing event-based programming Pro
model to web development. Component-based web frameworks are being o
touted as the future of Java web development, and Wicket is easily one of the
leading implementations in this area. Wicket strives for a clean separation of

the roles of HTML page designer and Java developer by supporting plain vanilla
W
HTML templates that can be mocked up, previewed, and later revised using
standard WYSIWYG HTML design tools.
Wicket counters the statelessness of HTTP by providing stateful components,
thereby improving productivity. If you are looking to hone your object-oriented Wicket
programming skills, Wicket fits well in that regard, since it has an architecture i
and rich component suite that encourages clean object-oriented design. c
Pro Wicketaims to get you up and running quickly with this framework. You
will learn how to configure Wicket and then gradually gain exposure to the
k
“Wicket way” of addressing web development requirements. You will learn
about important techniques of working with Wicket through simple examples.
People have come to expect a few things from a modern web framework— e
Spring framework integration and baked-in Ajax support are probably at the
top of that list. I have taken care to address these aspects of Wicket in the book.
t
You will learn to integrate Wicket and the EJB™3 API using the services of
Spring 2, for example. There is also a separate chapter dedicated to Wicket’s
integration with Ajax.
I have been having a great time with Wicket since day one of my adoption. I
wrote this book to let you know how Wicket, in addition to being a robust web
application framework, succeeds in bringing back the fun that has been missing
in the Java web development space.
Join online discussions:
Karthik Gurumurthy Explore this leading open source,lightweight,
forums.apress.com
FOR PROFESSIONALS component-based POJO web development framework
BY PROFESSIONALS™
THE APRESS JAVA™ ROADMAP
Companion eBook Pro Apache Geronimo
Beginning Hibernate Pro Hibernate 3
Beginning POJOs
Beginning Spring 2 Pro Spring
See last page for details
on $10 eBook version
G
Pro Wicket
u
r
u Karthik Gurumurthy
m
ISBN 1-59059-722-2 u
SOURCECODEONLINE r
www.apress.com 90000 th
y
Shelve in
Java Programming
User level:
Intermediate 6 89253 59722 4 9 781590 597224
this print for content only—size & color not accurate 7" x 9-1/4" / CASEBOUND / MALLOY
(0.8125 INCH BULK -- 328 pages -- 60# Thor)
7222FM.qxd 8/8/06 11:20 AM Page i
Pro Wicket
Karthik Gurumurthy
7222FM.qxd 8/8/06 11:20 AM Page ii
Pro Wicket
Copyright © 2006 by Karthik Gurumurthy
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information storage or retrieval
system, without the prior written permission of the copyright owner and the publisher.
ISBN-13: 978-1-59059-722-4
ISBN-10: 1-59059-722-2
Printed and bound in the United States of America 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication data is available upon request.
Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence
of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark
owner, with no intention of infringement of the trademark.
Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the US
and other countries.
Apress, Inc., is not affiliated with Sun Microsystems, Inc., and this book was written without endorsement
from Sun Microsystems, Inc.
Lead Editor: Steve Anglin
Technical Reviewers: David Heffelfinger, Igor Vaynberg
Editorial Board: Steve Anglin, Ewan Buckingham, Gary Cornell, Jason Gilmore, Jonathan Gennick,
Jonathan Hassell, James Huddleston, Chris Mills, Matthew Moodie, Dominic Shakeshaft,
Jim Sumser, Keir Thomas, Matt Wade
Project Manager: Kylie Johnston
Copy Edit Manager: Nicole LeClerc
Copy Editor: Ami Knox
Assistant Production Director: Kari Brooks-Copony
Production Editor: Laura Esterman
Compositor: Dina Quan
Proofreader: Lori Bring
Indexers: Toma Mulligan, Carol Burbo
Cover Designer: Kurt Krames
Manufacturing Director: Tom Debolski
Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor,
New York, NY 10013. Phone 1-800-SPRINGER, fax [phone], e-mail [email protected], or
visit http://www.springeronline.com.
For information on translations, please contact Apress directly at 2560 Ninth Street, Suite 219, Berkeley,
CA 94710. Phone [phone], fax [phone], e-mail [email protected], or visit http://www.apress.com.
The information in this book is distributed on an “as is” basis, without warranty. Although every precaution
has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to
any person or entity with respect to any loss or damage caused or alleged to be caused directly or indi-
rectly by the information contained in this work.
The source code for this book is available to readers at http://www.apress.comin the Source Code section.
7222FM.qxd 8/8/06 11:20 AM Page iii
To Amma and Appa for everything!
And to my wonderful wife,Gayathri
7222FM.qxd 8/8/06 11:20 AM Page iv
7222FM.qxd 8/8/06 11:20 AM Page v
Contents at a Glance
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
About the Technical Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
■ CHAPTER 1 Wicket:The First Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
■ CHAPTER 2 Validation with Wicket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
■ CHAPTER 3 Developing a Simple Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
■ CHAPTER 4 Providing a Common Layout to Wicket Pages . . . . . . . . . . . . . . . . . 117
■ CHAPTER 5 Integration with Other Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
■ CHAPTER 6 Localization Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
■ CHAPTER 7 Custom Wicket Components and Wicket Extensions . . . . . . . . . . . 199
■ CHAPTER 8 Wicket and Ajax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
■ CHAPTER 9 Additional Wicket Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
■ INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
v
7222FM.qxd 8/8/06 11:20 AM Page vi
7222FM.qxd 8/8/06 11:20 AM Page vii
Contents
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
About the Technical Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
■ CHAPTER 1 Wicket: The First Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
What Is Wicket? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Obtaining and Setting Up Wicket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Eclipse Development Environment Setup Using Quick Start . . . . . . . . . . . . 2
Running the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
How to Alter the Jetty Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The web.xml for Wicket Web Development . . . . . . . . . . . . . . . . . . . . . 4
Developing a Simple Sign-in Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Wicket Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
What Happened on Form Submit? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
How Does PropertyModel Work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
How to Specify a CompoundPropertyModel for a Page . . . . . . . . . . . . . . . 16
Development vs.Deployment Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Displaying the Welcome Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Adding a Link to the Welcome Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Adding Basic Authentication to the Login Page . . . . . . . . . . . . . . . . . . . . . . 32
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
■ CHAPTER 2 Validation with Wicket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Providing User Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
More Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Using Wicket Validators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Writing Custom Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Globally Registering a Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Registering String Converters Globally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
vii
7222FM.qxd 8/8/06 11:20 AM Page viii
viii ■ CONTENTS
How Wicket’s FormValidator Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
How to Set Session-Level Feedback Messages . . . . . . . . . . . . . . . . . . . . . 60
Changing Feedback Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
How the ListView Components Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
■ CHAPTER 3 Developing a Simple Application . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Securing Wicket Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Nice Wicket URLs and Mounted Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Accessing Wicket Application Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Developing an Online Bookstore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Where to Store Global Objects? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Books on Display at the Online Bookstore . . . . . . . . . . . . . . . . . . . . . . . . . . 78
How IDataProvider Allows for Pagination of Data . . . . . . . . . . . . . . . 79
What Is AbstractDetachableModel? . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
What Is LoadableDetachableModel? . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Wicket Pages and User Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Using Wicket Behaviors to Add HTML Attributes
to the Table Rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Implementing the Checkout Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Implementing the Remove Book Functionality . . . . . . . . . . . . . . . . 107
Checkout Confirmation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
IAuthorizationStrategy and Conditional Component Instantiation . . . . . 112
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
■ CHAPTER 4 Providing a Common Layout to Wicket Pages . . . . . . . . . . . 117
Adding “Books,”“Promotions,”and “Articles”Links
to the Bookstore Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Providing a Common Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Getting the Pages to Display Corresponding Titles . . . . . . . . . . . . . . . . . . 125
Separating Navigation Links and the Associated Page Content
Through Border Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Disabling Links to the Page Currently Being Displayed . . . . . . . . . . . . . . 135
Employing wicket:link to Generate Links . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Borders Are Not Just About Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
7222FM.qxd 8/8/06 11:20 AM Page ix
■ CONTENTS ix
■ CHAPTER 5 Integration with Other Frameworks . . . . . . . . . . . . . . . . . . . . . . 143
Wicket and Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Wicket and FreeMarker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
The Spring Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Difficulties in Spring Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Wicket Is an Unmanaged Framework . . . . . . . . . . . . . . . . . . . . . . . . 150
DI Issue Due to Wicket Model and Component Serialization . . . . . 151
Accessing the Spring ApplicationContext Through
the WebApplication Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Configuring Injection Through an IComponentInstantiationListener
Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Specifying Target Field for Dependency Injection . . . . . . . . . . . . . . . . . . . 159
Specifying Spring Dependency Through Java 5 Annotation . . . . . . . . . . 160
Spring Integration Through Commons Attributes . . . . . . . . . . . . . . . . . . . 164
How Wicket Integrates with EJB 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
A Quick EJB 3 Entity Bean Refresher . . . . . . . . . . . . . . . . . . . . . . . . 165
Choosing an EJB3 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Defining the persistence.xml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
How Spring 2.0 Further Simplifies EJB 3 Programming . . . . . . . . . . . . . 172
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
■ CHAPTER 6 Localization Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Localization Through the <wicket:message> Tag . . . . . . . . . . . . . . . . . . 177
Sources for Localized Messages and Their Search Order . . . . . . . . . . . . 179
How to Switch the Locale Programmatically . . . . . . . . . . . . . . . . . . . . . . . 183
How to Localize Validation and Error Messages . . . . . . . . . . . . . . . . . . . . 186
Putting Wicket’s StringResourceModel to Work . . . . . . . . . . . . . . . . 191
Locale-Specific Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Support for Skinning and Variation in Addition
to Locale-Specific Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Loading Messages from a Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198