Chapter 6: Inheritance and Abstract Classes Chapter Topics 6.1 ...

CS151 Object-Oriented Design
Dr. Kim
6.7 Hierarchy of Geometrical Shapes
This topic was covered in the Chapter 4. In this section, we will learn the use of template method
pattern in the design of shape classes.
6.7.1 Float/Double Classes
• Each RectangleShape class has two subclasses, e.g.
o Rectangle2D.Double/Rectangle2D.Float
o RoundRectangle2D.Double/RoundRectangle2D.Float
o Ellipse2D.Double/Ellipse2D.Float
• These logically related classes reside inside as static inner classes of Rectangle2D.
• Library designers provides the programmers with two different versions (.Double and
.Float)
o
o
An object of .Float version saves memory space.
• A float value occupies 32 bits while a double value occupies 64 bits.
• However, note that most of intermediate computations are done in double
precision.
Some application may need double precision.
public abstract class Rectangle2D extends RectangularShape
{
. . .
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