Additionally to the listeners provided by the JSF specification, RichFaces adds one more:
Ajax Listener (a4j:ajaxListener). Ajax Listener is invoked before the Render Response
phase. Instead of Action Listener or Value Change Listener which is not invoked when
Validation of the Update Model phases fails, Ajax Listener is guarantied to be invoked
for each Ajax Response. Hence, it is a good way to update a list of re-rendered
components, for example.
Ajax Listener is not invoked for a non-Ajax request and when RichFaces works in
"Ajax request generates Non-Ajax Response" mode. Therefore, Ajax Listener invocation
is a good indicator that Ajax Response is going to be processed.
type attribute defines the fully qualified Java class name for the listener. This
class should implement org.ajax4jsf.events.AjaxListener interface. You can access to
the source of the event (Ajax component) using event.getSource() call.