/**
 * GeomShapeDriver.java
 * Driver for the GeomShape class and its subclasses.
 * 
 * @author Scot Drysdale on 4/9/00.  Modified to use JApplet.
 * Minor changes by THC.
 */
import java.awt.*;
import javax.swing.*;

public class GeomShapeDriver extends JApplet {
	private static final long serialVersionUID = 1L;

	/**
	 * Initializes the applet
	 */
	public void init() {
		setBackground(Color.white);
		setSize(500, 500);
		Container cp = getContentPane();    // Content pane holds components
		cp.add(new Canvas());               // The canvas is the only component

		setVisible(true);   // Makes the applet (and its components) visible
	}

	/**
	 * Serves as the drawing canvas for graphics.
	 */
	private class Canvas extends JPanel {
		private static final long serialVersionUID = 1L;

		/**
		 * Paints this component.
		 * @param page the Graphics object that we draw on.  
		 */
		public void paintComponent(Graphics page) {
			super.paintComponent(page);

			GeomShape shape = null; // reference to an object that can be a Circle, Rect, or Segment

			for (int i = 1; i <= 3; i++) {
				if (i == 1) {
					shape = new Circle(300, 200, 75, Color.magenta);
					page.drawString("circle has area " + shape.areaOf(), 15, 20);
					shape.draw(page);
					((Circle) shape).scale(0.5); // note we must cast shape
				}
				else if (i == 2) {
					shape = new Rect(150, 200, 50, 25, Color.red);
					page.drawString("rectangle has area " + shape.areaOf(), 15, 40);
				}
				else if (i == 3) {
					shape = new Segment(20, 150, 100, 160, Color.blue);
					page.drawString("segment has area " + shape.areaOf(), 15, 60);
				}

				// Notice the polymorphism: the first time through the loop,
				// shape references a Circle, the second time it references a Rect,
				// and the third time it references a Segment.  With dynamic binding,
				// the appropriate draw and move methods are called each time.
				shape.draw(page);
				shape.move(-5, -35);
				shape.draw(page);
			}
		}
	}
}