Shape Hierarchy
Now consider the Shape
inheritance hierarchy in Fig. 9.3. This hierarchy begins with superclass Shape
, which is extended by subclasses TwoDimensionalShape
and ThreeDimensionalShape
—Shape
s are either TwoDimensionalShape
s or ThreeDimensionalShape
s. The third level of this hierarchy contains specific types of TwoDimensionalShape
s and ThreeDimensionalShape
s. As in Fig. 9.2, we can follow the arrows from the bottom of the diagram to the topmost superclass in this class hierarchy to identify several is-a relationships. For example, a Triangle
is a TwoDimensionalShape
and is a Shape
, while a Sphere
is a ThreeDimensionalShape
and is a Shape
. This hierarchy could contain many other classes. For example, ellipses and trapezoids also are ...
Get Java™ How To Program (Early Objects), Tenth Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.