Subject - object with views

Description

       A  subject  is  an  object  that  has  one  or  more views that it wishes to notify when it changes.  The
       SubjectIteractor class can be used if it  is  necessary  to  iterate  through  the  views  of  a  subject
       explicitly.

       Because subjects are shared, Subject is a subclass of Resource.  To allow for the possibility of multiple
       inheritance, in which case only a single copy of resource information should be maintained, Resource is a
       virtual base class.

Name

       Subject - object with views

Public Operations

enumUpdateHint{attaching,detaching,setting,changing}
              This  type  enumerates possible hints when a subject is notifying a view that it has changed.  The
              attaching hint indicates that a view has attached to the subject.  The detaching hint  means  that
              the subject is being deleted and the view should consider itself detached.  The setting hint means
              that  the  subject's value has been set, though possibly to the same value as it already has.  The
              changing hint means that the value is set to something different than it was previously.

       virtualvoidattach(View*)
              Add a view to the subject's list.

       virtualvoiddetach(View*)
              Remove a view from the subject's list.

       virtualvoidnotify(UpdateHint=changing)
              Notify all the views of a subject that it has been updated.

       virtualbooleanviewed_by(View*)
              Return whether a given view is on the subject's list of views.

       virtualvoidAttach(Interactor*)
              This function is equivalent to attach and is provided solely for backward compatibility.  It  will
              be removed in a future version.

       virtualvoidDetach(Interactor*)
              This  function is equivalent to detach and is provided solely for backward compatibility.  It will
              be removed in a future version.

       virtualvoidNotify()
              This function is equivalent to notify(changing) and is provided solely for backward compatibility.
              It will be removed in a future version.

       booleanIsView(Interactor*)
              This function is equivalent to viewed_by and is provided solely for  backward  compatibility.   It
              will be removed in a future version.

Subjectiterator Operations

       A subject iterator can be used to iterate through the views in a subject.

       SubjectIterator(Subject*)
              Create  a  subject  iterator  for  the  given  subject.  The iterator is only valid as long as the
              subject exists.

       virtualvoidinit()
              Reset the iteration to start at the beginning of the  list.   This  operation  is  called  by  the
              constructor.

       virtualbooleanmore()
              Return whether there are more views in the list.

       virtualView*cur()
              Return the current view.

       virtualvoidremove()
              Remove the current view from the list.

       virtualvoidnext()
              Move the iteration to the next view in the list.