StateVarView(3U)					    InterViews Reference Manual 					  StateVarView(3U)

NAME

       StateVarView - state variable view base class

SYNOPSIS

       #include <Unidraw/stateview.h>

DESCRIPTION

       StateVarView  is  the base class for state variable views.  State variable views provide a graphical interface to examining and potentially
       modifying a state variable subject.  The StateVarView base class is an abstract class derived from MonoScene.  Like MonoScene,  the  State-
       VarView	class  is not instantiated; instead, subclasses add state and behavior appropriate for displaying and editing their subject.  Like
       other MonoScene subclasses, StateVarView subclasses use an interactor composition to define their appearance.

PUBLIC OPERATIONS

       virtual void Update()
	      Update the state variable view in response to a change in state it depends on (typically the subject's).	This  operation  does  not
	      normally need redefinition if Init and Stale (described below) are redefined.

PROTECTED OPERATIONS

       StateVarView(StateVar*)
	      Subclass	constructors  normally take an instance of the corresponding subject as an argument.  The base class constructor automati-
	      cally attaches the view to the subject.

       virtual void Init()
	      Initialize the view based on information in the subject.	Subclasses redefine this operation according to their semantics;  it  does
	      nothing by default.

       virtual boolean Stale()
	      Return  whether the view is in any way inconsistent with its subject.  This operation always returns true by default; subclasses can
	      redefine it to make a more discerning decision.

SEE ALSO

       MonoScene(3I), StateVar(3U)

Unidraw 							   6 August 1990						  StateVarView(3U)