public class Rectangle extends Shape implements Stretchable { public Rectangle( double len, double wid ) { length = len; width = wid; } public double area( ) { return length * width; } public double perimeter( ) { return 2 * ( length + width ); } public String toString( ) { return "Rectangle: " + length + " " + width; } public double getLength( ) { return length; } public double getWidth( ) { return width; } public void stretch( double factor ) { if( factor <= 0 ) throw new IllegalArgumentException( ); if( length > width ) length *= factor; else width *= factor; } private double length; private double width; }