We developed this recipe with NetBeans 6.8, JSF 2.0, and GlassFish v3. The JSF 2.0 classes were obtained from the NetBeans JSF 2.0 bundled library.

Starting with the f:event tag, we can say that this is a simple tag that should be fitted in the right place and configured with its two simple attributes. Speaking of fitting it in the right place, you should know that f:event can be placed in any component that you want—for example we put it in an h:inputText component:

…
<h:inputText value="#{bean.number}">
<f:event type="preRenderComponent"
listener="#{bean.initNumber}" />
</h:inputText>
…

As you can see there are two attributes of the f:event tag, named type and listener. The value of the type attribute represents the name of the event for which to install a listener (in our example, we have used the preRenderComponent value—with other words, before the component is rendered). In the following table are the possible values, and the corresponding event type for which the listener action is registered.

The listener attribute's value represents a MethodExpression pointing to a method that will be called when the listener's processEvent method would have been called. In our example, that method is named initNumber and it can be seen in the following managed bean:

package beans;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
@ManagedBean
@SessionScoped
public class Bean {
private String number = "";
public Bean() {
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public void initNumber(){
setNumber("2010");
}
}

While f:event works only with predefined events, the @NamedEvent provides support for exposing custom events. The application developer can make a custom event available to the page authors using the @NamedEvent annotation. This annotation can be placed on custom events to register them with the runtime, making them available to f:event. When the application starts, JSF scans for a set of annotations, including @NamedEvent. If it is found on a class, the following logic is applied to get the name/names for the event:

The code bundled with this book contains a complete example of this recipe. The project can be opened with NetBeans 6.8 and it is named: JSF_declarative_event_handling.