Presentation about Apache Wicket given at FOSDEM 2011. Apache Wicket is an open source, component oriented Java web framework. This presentation features an introduction to the Wicket framework and showcases some of the new features in the upcoming 1.5 release of Wicket.

1. Introducing
Apache Wicket
Martijn Dashorst

2. Agenda
• Introduction to Apache Wicket
• New and noteworthy in 1.5
• Questions

3. Martijn Dashorst
• Employee @ Topicus
• Chair for Apache Wicket
• Committer
• Apache Member
• Author Wicket in Action

4. Introduction

5. Wicket is...
a component oriented web framework
using just HTML and Java

6. Apache Wicket
• Open Source: ASL 2.0
• Created in 2004
• Java web framework
• Component oriented
• http://wicket.apache.org

7. Who’s using Wicket?

25. mobile.walmart.com supports three categories
of devices using the same Java code (only the html
is (very) different.)
Try doing that with JSP.
— Joachim Kainz

26. ... We at Vegas.com have been able to re-
purpose our Wicket-based air/hotel search
application and purchase/checkout application.
This is the new mexico.com. [...]
The re-use of components and abstract pages
was tremendous.
—Scott Swank, chief architect vegas.com

27. Just HTML

28. Sign up form
Example from Railscast episode #250

29. Sign up form

30. Sign up form
<h1>Sign Up</h1>
<form>
<div class="error_messages">
<h2>Form is invalid</h2>
<ul>
<li>Some error message</li>
</ul>
</div>
<p>
<label for="email">E-Mail</label><br/>
<input type="email" id="email" />
</p>
<p>
<label for="password">Password</label>
<input type="password" id="password" />
</p>
<p>
<label for="confirm">Password confirmat
<input type="password" id="confirm" />
</p>
<p class="button"><input type="submit" va

31. Sign up form

32. Sign up form
<h1>Sign Up</h1>
<%= form_for @user do |f| %>
<% if @user.errors.any? %>
<div class="error_messages">
<h2>Form is invalid</h2>
<ul>
<% for message in @user.errors.full
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<p>
<%= f.label :email %><br />
<%= f.text_field :email %>
</p>
<p>
<%= f.label :password %><br />
<%= f.password_field :password %>
</p>
<p>

33. Sign up form
<h1>Sign Up</h1>
<form>
<div class="error_messages">
<h2>Form is invalid</h2>
<ul>
<li>Some error message</li>
</ul>
</div>
<p>
<label for="email">E-Mail</label><br/>
<input type="email" id="email" />
</p>
<p>
<label for="password">Password</label>
<input type="password" id="password" />
</p>
<p>
<label for="confirm">Password confirmat
<input type="password" id="confirm" />
</p>
<p class="button"><input type="submit" va

34. Sign up form
<h1>Sign Up</h1>
<form>
<div wicket:id="feedback" class="error_me
<h2>Form is invalid</h2>
<ul>
<li>Some error message</li>
</ul>
</div>
<p>
<label for="email">E-Mail</label><br/>
<input wicket:id="email" type="email" i
</p>
<p>
<label for="password">Password</label>
<input wicket:id="password" type="passw
</p>
<p>
<label for="confirm">Password confirmat
<input wicket:id="confirm" type="passwo
</p>
<p class="button"><input type="submit" va

35. Sign up form
<h1>Sign Up</h1>
<form>
<div wicket:id="feedback" class="error_me
<h2>Form is invalid</h2>
<ul>
<li>Some error message</li>
</ul>
</div>
<p>
<label for="email">E-Mail</label><br/>
<input wicket:id="email" type="email" i
</p>
<p>
<label for="password">Password</label>
<input wicket:id="password" type="passw
</p>
<p>
<label for="confirm">Password confirmat
<input wicket:id="confirm" type="passwo
</p>
<p class="button"><input type="submit" va

36. <tag wicket:id="foo">
Instructs Wicket to work on this tag

37. Imperative markup
<h1>Sign Up</h1>
• Used by Ruby on Rails, <%= form_for @user do |f| %>
<% if @user.errors.any? %>
JSP, Play, Velocity, ... <div class="error_messag
<h2>Form is invalid</h
•
<ul>
Great for web developers <% for message in @u
<li><%= message %>
• Great for hacking on a <% end %>
</ul>
web site </div>
<% end %>
<p>
• Code and markup are <%= f.label :email %><br
<%= f.text_field :email
not separated </p>
<p>

38. Declarative markup
<h1>Sign Up</h1>
• Used by Wicket, Tapestry, <form wicket:id="form">
<div class="error_message
Facelets <p>
<label for="email">E-Ma
• Great for web designers
<input type="email" id=
</p>
<p>
• Go from PSD → HTML → <label for="password">P
<input type="password"
Page → Component </p>
<p>
<label for="confirm">Pa
• Code and markup are <input type="password"
</p>
strictly separated <p class="button"><input
</form>

39. Just Java

40. Sign up form
<h1>Sign Up</h1>
<%= form_for @user do |f| %>
<% if @user.errors.any? %>
<div class="error_messages">
<h2>Form is invalid</h2>
<ul>
<% for message in @user.errors.full_messages %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<p>
<%= f.label :email %><br />
<%= f.text_field :email %>
</p>
<p>
<%= f.label :password %><br />
<%= f.password_field :password %>
</p>
<p>
<%= f.label :password_confirmation %>

41. Sign up form
Form form = new Form("signup") {
@Override
public void onSubmit() {
// ...
}
}
add(form);

42. Sign up form
Form form = new Form("signup") {
@Override
public void onSubmit() {
// ...
}
}
add(form);
FeedbackPanel feedback = new FeedbackPanel("feedback");
feedback.setVisible(form.hasFeedbackMessages());
form.add(feedback);

43. Sign up form
Form form = new Form("signup") {
@Override
public void onSubmit() {
// ...
}
}
add(form);
FeedbackPanel feedback = new FeedbackPanel("feedback");
feedback.setVisible(form.hasFeedbackMessages());
form.add(feedback);
form.add(new EmailTextField("email", Model.of(""))
.setRequired(true));

44. Sign up form
Form form = new Form("signup") {
@Override
public void onSubmit() {
// ...
}
}
add(form);
FeedbackPanel feedback = new FeedbackPanel("feedback");
feedback.setVisible(form.hasFeedbackMessages());
form.add(feedback);
form.add(new EmailTextField("email", Model.of(""))
.setRequired(true));
form.add(new PasswordField("password", Model.of(""))
.setRequired(true));

45. Sign up form
Form form = new Form("signup") {
@Override
public void onSubmit() {
// ...
}
}
add(form);
FeedbackPanel feedback = new FeedbackPanel("feedback");
feedback.setVisible(form.hasFeedbackMessages());
form.add(feedback);
form.add(new EmailTextField("email", Model.of(""))
.setRequired(true));
form.add(new PasswordField("password", Model.of(""))
.setRequired(true));
form.add(new PasswordField("confirm", Model.of(""))
.setRequired(true));

46. Just Java
• No logic in markup
• Components are objects (use new and extends)
• Use OO techniques in your programming
• No XML

47. Concepts

48. Components
• Manipulate markup
• Render content
• Receive events (onClick, onSubmit)
• Examples:
Label, Link, Form, TextField, PagingNavigator, Panel,
Page, ClientSideImageMap

49. Models
• Provide data to components
• Store data for components
• Transform data
• Retrieve data from persistent storage
• Examples: Model<T>, PropertyModel<T>

50. Behaviors
• Decorator/Adapter for Component
• Can manipulate markup of Component
• Can receive events (onClick)
• Add Ajax functionality to components
• Example: AjaxSelfUpdatingTimerBehavior

51. Getting started

52. Wicket projects
• Apache Wicket • Leg before Wicket
(extensions, spring, guice, velocity, etc) (Maven archetypes)
• Wicket stuff • Apache Isis
(grand collection of projects) (incubating, DDD framework)
• Seam for Apache • Jolira Tools
Wicket (powers mobile.walmart.com)
• WiQuery • Visural Wicket
(standalone Wicket components)
(JQuery integration library)

53. Apache Wicket projects
• Core • Velocity
• Extensions • Auth/Roles
• Quick start • JMX
• IoC • Dev utils
• Spring
• Guice • Examples
• DateTime

54. Wicket Stuff projects
• progressbar • shiro-security • theme
• datatable-autocomplete • gae-initializer • yav
• flot • push-jdk-1.5 • maven-support
• googlecharts • jasperreports • plugin
• scala-extensions • mbeanview • input-events
• openlayers • jsr303 • javaee-inject
• gmap2 • client-and-server-validation • push
• inmethod-grid • multi-text-input • wicket-html5
• minis • prototype • wicket-servlet3
• phonebook • simile-timeline

55. Quick start

56. Quick start

57. Running quickstart
$_

58. Running quickstart
$ mvn -o archetype:generate -DarchetypeGroupId=org.apache.wicket -
DarchetypeArtifactId=wicket-archetype-quickstart -DarchetypeVersion=1.5-
SNAPSHOT -DgroupId=com.mycompany -DartifactId=myproject -
DarchetypeRepository=https://repository.apache.org/content/repositories/
snapshots/ -DinteractiveMode=false _

59. Running quickstart
$ mvn -o archetype:generate -DarchetypeGroupId=org.apache.wicket -
DarchetypeArtifactId=wicket-archetype-quickstart -DarchetypeVersion=1.5-
SNAPSHOT -DgroupId=com.mycompany -DartifactId=myproject -
DarchetypeRepository=https://repository.apache.org/content/repositories/
snapshots/ -DinteractiveMode=false
[INFO] Scanning for projects...
[INFO] -----------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] -----------------------------------------------------------
[INFO] >>> maven-archetype-plugin:2.0:generate (default-cli) >>>
[INFO] <<< maven-archetype-plugin:2.0:generate (default-cli) <<<
[INFO] --- maven-archetype-plugin:2.0:generate (default-cli) ---
[INFO] Generating project in Batch mode
[INFO] Archetype defined by properties
[INFO] -----------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] -----------------------------------------------------------
[INFO] Total time: 1.279s
[INFO] Finished at: Fri Feb 04 22:04:14 CET 2011
[INFO] Final Memory: 9M/81M
[INFO] -----------------------------------------------------------

60. Running quickstart
$ mvn jetty:run_

61. Running quickstart
$ mvn jetty:run
[INFO] Scanning for projects...
[INFO] -----------------------------------------------------------
[INFO] Building quickstart 1.0-SNAPSHOT
[INFO] -----------------------------------------------------------
[INFO] Starting jetty 7.2.2.v20101205 ...
2011-02-04 22:04:34.969:INFO::jetty-7.2.2.v20101205
2011-02-04 22:04:35.198:INFO::No Transaction manager found - if yo
INFO - WebXmlFile - web.xml: found filter with na
INFO - Application - [wicket.myproject] init: Wick
INFO - RequestListenerInterface - registered listener interface
INFO - WebApplication - [wicket.myproject] Started Wi
******************************************************************
*** WARNING: Wicket is running in DEVELOPMENT mode. ***
*** ^^^^^^^^^^^ ***
*** Do NOT deploy to your live server(s) without changing this.***
*** See Application#getConfigurationType() for more information***
******************************************************************
2011-02-04 22:04:35.464:INFO::Started SelectChannelConnector@0.0.0.0:8080
[INFO] Started Jetty Server

62. Running quickstart

63. Quick start alternative
Leg up
• Spring
• Guice
• JDBC
• JPA
• Hibernate
• Scala
http://jweekend.com/dev/LegUp

64. Want to learn more?

65. Want to learn more?

66. Want to learn more?
http://wicket.apache.org/learn/books.html

67. Examples

68. Examples
Hello, World!

69. Hello, World!
<h1>Hello, World</h1>

70. Hello, World!
<h1>[Replaced text]</h1>

71. Hello, World!
<h1 wicket:id="msg">[Replaced text]</h1>

72. Hello, World!
<h1 wicket:id="msg">[Replaced text]</h1>
+
add(new Label("msg", "Hello, World!"));

73. Hello, World!
<h1 wicket:id="msg">[Replaced text]</h1>
+
add(new Label("msg", "Hello, World!"));
=
<h1>Hello, World!</h1>

74. Examples
Click counter

75. This link has been clicked 123 times

76. This link has been clicked 123 times
This link has been clicked 123 times!

77. This link has been clicked 123 times
This <a href="#">link</a> has been clicked 123
times!

78. This link has been clicked 123 times
This <a href="#">link</a> has been clicked
<span>123</span> times!

79. This link has been clicked 123 times
This <a wicket:id="link" href="#">link</a> has been
clicked <span>123</span> times!

80. This link has been clicked 123 times
This <a wicket:id="link" href="#">link</a> has been
clicked
<span wicket:id="clicks">123</span> times!

81. This link has been clicked 123 times
This <a wicket:id="link" href="#">link</a> has been
clicked
<span wicket:id="clicks">123</span> times!

82. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
}

83. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
public ClickCountPage() {
}
}

84. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCountPage() {
}
}

85. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCountPage() {
add(new Link<Void>("link") {
public void onClick() {
clicks++;
}
});
}

86. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCountPage() {
add(new Link<Void>("link") { ... });
add(new Label("clicks",
new PropertyModel<Integer>(this,
"clicks")));
}
}

87. Wicket for developers

88. 2 modes for your app
Development and Deployment

89. Development mode
$ mvn jetty:run
[INFO] Scanning for projects...
[INFO] -----------------------------------------------------------
[INFO] Building quickstart 1.0-SNAPSHOT
[INFO] -----------------------------------------------------------
[INFO] Starting jetty 7.2.2.v20101205 ...
2011-02-04 22:04:34.969:INFO::jetty-7.2.2.v20101205
2011-02-04 22:04:35.198:INFO::No Transaction manager found - if yo
INFO - WebXmlFile - web.xml: found filter with na
INFO - Application - [wicket.myproject] init: Wick
INFO - RequestListenerInterface - registered listener interface
INFO - WebApplication - [wicket.myproject] Started Wi
******************************************************************
*** WARNING: Wicket is running in DEVELOPMENT mode. **
*** ^^^^^^^^^^^ **
*** Do NOT deploy to your live server(s) without changing this. **
*** See Application#getConfigurationType() for more information **
******************************************************************
2011-02-04 22:04:35.464:INFO::Started SelectChannelConnector@0.0.0.0:8080
[INFO] Started Jetty Server

90. Development mode
• exceptional error pages
• dynamic markup reloading
• no caching
• no javascript/css optimizations
• discover mistakes early (serialization, missing
components, ...)
• Wicket debugger visible

91. Deployment mode
• Cache markup resources
• No checks
• Don’t display stack traces to users
• Minimize/compress JavaScript
• Don’t generate wicket tags
• Wicket debugger not visible

92. FREE PRO TIP:
Don’t perform your performance tests
in development mode!

93. Ajax debugger

94. Ajax debugger

95. Ajax envelope
<?xml version="1.0" encoding="UTF-8"?>
<ajax-response>
<component id="count2">
<![CDATA[<span wicket:id="count" id="count2">1</span>]]>
</component>
</ajax-response>

96. Error message
Unable to find component with id 'count'
in HomePage.
This means that you declared
wicket:id=count in your markup, but that
you either did not add the component to
your page at all, or that the hierarchy does
not match.

97. Error pages

98. Testing the UI

99. WicketTester
• Test components directly, or their markup
• Runs tests without starting server
• Ajax testing (server side)
• Runs in IDE, ant, maven builds
• Achieves high code coverage

100. Testing Hello, World!
@Test
public void rendersWelcomeMessage() {
}

101. Testing Hello, World!
@Test
public void rendersWelcomeMessage() {
WicketTester tester = new WicketTester();
}

102. Testing Hello, World!
@Test
public void rendersWelcomeMessage() {
WicketTester tester = new WicketTester();
tester.startPage(HelloWorldPage.class);
}

103. Testing Hello, World!
@Test
public void rendersWelcomeMessage() {
WicketTester tester = new WicketTester();
tester.startPage(HelloWorldPage.class);
tester.assertLabel("msg", "Hello, World!");
}

104. Testing Click Count
@Test
public void clicksIncreaseCount() {
}

105. Testing Click Count
@Test
public void clicksIncreaseCount() {
WicketTester tester = new WicketTester();
}

106. Testing Click Count
@Test
public void clicksIncreaseCount() {
WicketTester tester = new WicketTester();
tester.startPage(ClickCountPage.class);
}

107. Testing Click Count
@Test
public void clicksIncreaseCount() {
WicketTester tester = new WicketTester();
tester.startPage(ClickCountPage.class);
tester.assertModelValue("clicks", 0);
}

108. Testing Click Count
@Test
public void clicksIncreaseCount() {
WicketTester tester = new WicketTester();
tester.startPage(ClickCountPage.class);
tester.assertModelValue("clicks", 0);
tester.clickLink("link");
}

109. Testing Click Count
@Test
public void clicksIncreaseCount() {
WicketTester tester = new WicketTester();
tester.startPage(ClickCountPage.class);
tester.assertModelValue("clicks", 0);
tester.clickLink("link");
tester.assertModelValue("clicks", 1);
}

110. Other test frameworks
• PageTest (by Kent Tong)
• JDave (BDD framework)

111. Summary
• Widely used
• Component oriented
• Java
• Open Source (ASL 2.0)

112. What’s new in 1.5?

113. HTML 5 support

114. Pre 1.5
• Checks for valid markup don’t accept new field types
• HTML 5 defines:
<input type=”text|email|password|number|date|
search|url|...”>

115. Wicket 1.5
• EmailTextField
• NumberTextField
• UrlTextField
• RangeTextField

116. Improved internals

117. Split up core library
• Old:
• wicket.jar

118. Split up core library
• Old:
• wicket.jar
• New:
• wicket-requests.jar
• wicket-util.jar
• wicket-core.jar

119. Maven users
<dependency>
<groupId>org.apache.wicket</groupId>
<artifactId>wicket-core</artifactId>
<version>1.5-RC1</version>
</dependency>

120. Simpler request cycle

121. Wicket < 1.5
• Decoding request and handling in state machine
• Debugging ‘interesting’
• Designed for flexibility
• Served its purpose—took on 4 years of engineering

122. Wicket 1.5
• Request cycle processing completely rewritten
• Rendering code has been improved and simplified
• URL rendering simplified: now in one place

123. Wicket < 1.5
• Custom request cycle: subclass WebRequestCycle
• Problematic with add-ons:
• HibernateRequestCycle
• SecureRequestCycle
• ActivityRequestCycle

124. New: RequestCycleListener
public interface IRequestCycleListener {
void onBeginRequest(RequestCycle cycle);
void onEndRequest(RequestCycle cycle);
void onDetach(RequestCycle cycle);
IRequestHandler onException(RequestCycle cycle, Exception ex);
}

125. RequestCycleListener
public class SomeWebApplication extends WebApplication {
@Override
protected void init() {
}
@Override
public Class<? extends Page> getHomePage() {
return SomePage.class;
}
}

126. RequestCycleListener
public class SomeWebApplication extends WebApplication {
@Override
protected void init() {
addRequestCycleListener(new IRequestCycleListener() {
public void onBeginRequest() {
// do something at the beginning of the request
}
public void onEndRequest() {
// do something at the end of the request
}
public void onException(Exception ex) {
// do something here when there's an exception
}
});
}
@Override
public Class<? extends Page> getHomePage() {
return SomePage.class;
}
}

127. Switching to HTTPS

128. Switching to HTTPS
public SecurePage extends WebPage {
...
}
public MyApplications extends WebApplication {
@Override
public void init() {
super.init();
}
}

129. Switching to HTTPS
@RequireHttps
public SecurePage extends WebPage {
...
}
public MyApplications extends WebApplication {
@Override
public void init() {
super.init();
}
}

130. Switching to HTTPS
@RequireHttps
public SecurePage extends WebPage {
...
}
public MyApplications extends WebApplication {
@Override
public void init() {
super.init();
setRootRequestMapper(
new HttpsMapper(getRootRequestMapper(),
new HttpsConfig());
}
}

131. Component event bus

132. Component event bus
• IEventSource: objects that send events
<T> void send(IEventSink sink,
Broadcast broadcast, T payload);
• IEventSink: objects that receive events
void onEvent(IEvent<?> event);
• Participants: Components, RequestCycle, Session and
Application

133. Event bus example
Ajax link counter

134. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new Link<Void>("link") {
@Override
public void onClick() {
count++;
}
});
add(new Label("clicks",
new PropertyModel<Integer>(this, "clicks")));
}
}

135. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new Link<Void>("link") {
@Override
public void onClick() {
count++;
}
});
add(new Label("clicks",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

136. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
}
});
add(new Label("clicks",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

137. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
target.add(getPage().get("count"));
}
});
add(new Label("count",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

138. This link has been clicked 123 times
public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
target.add(getPage().get("count"));
}
});
add(new Label("count",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

139. Pre-event bus
• Link needs to know the updatable components
• Makes code brittle, hard to maintain
• Better:
• Let the label refresh itself with each Ajax request

140. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
target.add(getPage().get("count"));
}
});
add(new Label("count",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

141. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
send(getPage(), Broadcast.BREADTH, target);
}
});
add(new Label("count",
new PropertyModel<Integer>(this, "clicks"))
.setOutputMarkupId(true));
}
}

142. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") {
@Override
public void onClick(AjaxRequestTarget target) {
count++;
send(getPage(), Broadcast.BREADTH, target);
}
});
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
}

143. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") { ... });
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
public class CountLabel extends Label {
}
}

144. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") { ... });
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
public class CountLabel extends Label {
public CountLabel(String id, IModel<Integer> model) {
super(id, model);
}
}
}

145. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") { ... });
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
public class CountLabel extends Label {
public CountLabel(String id, IModel<Integer> model) {
super(id, model);
setOutputMarkupId(true);
}
}
}

146. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") { ... });
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
public class CountLabel extends Label {
public CountLabel(String id, IModel<Integer> model) {
super(id, model);
setOutputMarkupId(true);
}
@Override
public void onEvent(IEvent<?> event) {
super.onEvent(event);
}
}
}

147. public class ClickCountPage extends WebPage {
private int clicks = 0;
public ClickCount() {
add(new AjaxLink<Void>("link") { ... });
add(new CountLabel("count", new PropertyModel<Integer>(this,
}
public class CountLabel extends Label {
public CountLabel(String id, IModel<Integer> model) {
super(id, model);
setOutputMarkupId(true);
}
@Override
public void onEvent(IEvent<?> event) {
super.onEvent(event);
if (event.getPayload() instanceof AjaxRequestTarget) {
AjaxRequestTarget target =
(AjaxRequestTarget) event.getPayload();
target.add(this);
}
}
}
}

148. Post-event bus
• A bit more code
• Updates are now completely decoupled
• Make the payload type safe and meaningful:
no AjaxRequestTarget, but CountEvent
• AJAX requests trigger a default event with an
AjaxRequestTarget as payload

149. And much, much more:
http://cwiki.apache.org/WICKET/
migration-to-wicket15.html

150. Thank you!
Questions? Ask!