Visual Modeling with Rational Rose 2002 and UML

Inheritance Trees

The basis for specialization (i.e., why subclasses were created) in an inheritance relationship is called the discriminator. The discriminator typically has a finite set of values and subclasses that may be created for each value. For example, one basis for discrimination for a Course class is the location of the course—OnCampusCourse and OffSiteCourse could be two subclasses of the Course class based on this discriminator. The inheritance relationship may be shown as a tree for all subclasses created from one discriminator. Another subclass of Course could be MandatoryCourse. This subclass would not be part of the inheritance tree because it belongs to a different discriminator—course type. Care must be taken when you discover ...