A lifecycle method invoked during the dispatch phase, where a http request is translated to a dispatch
(a path in the page tree) ultimately leading to an action invocation. This method is invoked after
the PageInstance has been injected by the framework.
Also, this method is invoked on this object after it has been invoked on the PageAction corresponding
to the parent page, if any.
either null, meaning that the dispatch process is to go forward regularly, or a Resolution to be
executed, interrupting normal action invocation.