Apache Wicket releases Wicket 1.5

07 Sep 2011

The Apache Wicket team is proud to announce the immediate availability of the newest release of their component oriented open source Java web framework. Apache Wicket 1.5 has been in development for the last two years and brings many improvements over previous versions.

Downloading Apache Wicket 1.5

You can download the release here: http://www.apache.org/dyn/closer.cgi/wicket/1.5.0

Or use this in your Maven POM to upgrade to the new version:

<dependency>
    <groupId>org.apache.wicket</groupId>
    <artifactId>wicket-core</artifactId>
    <version>1.5.0</version>
</dependency>

Please note that Wicket’s main artifact ID has been renamed to wicket-core.

You will need to upgrade all modules (i.e. wicket, wicket-extensions, wicket-ioc, wicket-spring, etc) to 1.5.0. It is not possible to mix previous versions of Wicket with modules of this release.

Most notable changes

With this release the Wicket team has revised many of its internals. A short list:

• HTML5 components added: EmailTextField, NumberTextField, UrlTextField and RangeTextField
• New inter-component events (explained below)
• Minimum required servlet API is servlet-api 2.5
• All standard validators now extend Behavior to allow for client side validations
• IBehavior has been removed and AbstractBehavior has been deprecated, you should now extend Behavior instead
• Simplified the request cycle processing and made it more extensible
• URL handling is now in one place
• Wicket’s rendering code has been greatly simplified
• Improved browser caching support
• ClientSideImageMap replaces old ImageMap
• Better support for running behind proxies with x-forwarded-for header
• Request cycle listeners make it easier to integrate frameworks in your Wicket application
• Consistent naming: methods with Javascript in the name have been renamed to use proper capitalization: JavaScript
• Switching to HTTPS is as simple as configuring a new root mapper to make Wicket HTTPS aware and annotating a page with @RequireHttps

A longer list of changes and improvements can be found in our migration guide.

Inter-component events

Wicket 1.5 offers a simple, yet flexible, way for component to communicate with each other in a decoupled manner. The two major interfaces that facilitate this are:

/**
 * Objects that can send events
 */
public interface IEventSource {
    <T> void send(IEventSink sink, Broadcast broadcast, T payload);
}

and

/**
 * Objects that can receive events
 */
public interface IEventSink
{
    /**
     * Called when an event is sent to this sink
     */
    void onEvent(IEvent<?> event);
}

The classes that implement these interfaces, and can thus participate in the event mechanism are: Component, RequestCycle, Session, and Application.

The mechanism allows for different event broadcast methods defined here:

/**
 * Defines the event broadcast type.
 */
public enum Broadcast {
    BREADTH,
    DEPTH,
    BUBBLE,
    EXACT;
}

There is an example in wicket-examples which demonstrates the usage of this.

Applications can register custom event dispatchers in FrameworkSettings; the dispatchers can be used to build custom event delivery mechanisms. For example a custom IEventDispatcher mechanism can route events to annotated methods, for example:

public class MyComponent extends Component {
    @OnEvent
    private void onUserAdded(UserAddedEvent event) {...}
}

where UserAddedEvent is the event payload object.

The default Component#onEvent method will be called even if custom dispatchers are registered.

A default event is raised whenever Wicket begins to create an AJAX response. The payload of the event is the AjaxRequestTarget used for event. Sample implementation:

// component that always adds itself to the ajax response
public class MyComponent extends Component {
    public void onEvent(IEvent event) {
        if (event.getPayload() instanceof AjaxRequestTarget) {
            ((AjaxRequestTarget)event.getPayload()).add(this);
         }
    }
}