Author(s)Chris Turner, Eelco Hillenius, Jonathan Locke
This provide a base class to work with detachable IModel s.
It encapsulates the logic for attaching and detaching models. The
onAttach() abstract method will be called at the first access to the model
within a request and - if the model was attached earlier, onDetach() will be
called at the end of the request. In effect, attachment and detachment is
only done when it is actually needed.