import java.awt.Rectangle; /** This program demonstrates the use of a Measurer. */ public class MeasurerTester { public static void main(String[] args) { class AreaMeasurer implements Measurer { public double measure(Object anObject) { Rectangle aRectangle = (Rectangle) anObject; double area = aRectangle.getWidth() * aRectangle.getHeight(); return area; } } Measurer areaMeas = new AreaMeasurer(); Rectangle[] rects = new Rectangle[] { new Rectangle(5, 10, 20, 30), new Rectangle(10, 20, 30, 40), new Rectangle(20, 30, 5, 15) }; double averageArea = Data.average(rects, areaMeas); System.out.println("Average area: " + averageArea); System.out.println("Expected: 625"); } }