/** Based on textbook section 12.1
 */
import java.awt.event.*;        // for mouse listener
import java.awt.*;              // for graphics
import javax.swing.*;           // for JPanel

public class RectanglePanel extends JPanel
{
  private Rectangle box;
  private static final int BOX_X = 100;
  private static final int BOX_Y = 100;
  private static final int BOX_HEIGHT = 30;
  private static final int BOX_WIDTH = 20;
  private static final int PANEL_HEIGHT = 300;
  private static final int PANEL_WIDTH = 300;

  // constructor - create a panel at some default location
  public RectanglePanel()
  {
    // inner class is mouse listener
    class DetectInput implements MouseListener
    {
      public void mousePressed(MouseEvent e)
	  {
        int x = e.getX();
        int y = e.getY();
        box.setLocation(x, y);
        repaint();
      }
      public void mouseReleased(MouseEvent e) {}
      public void mouseClicked(MouseEvent e) {}
      public void mouseEntered(MouseEvent e) {}
      public void mouseExited(MouseEvent e) {}
    }

    setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT));
    box = new Rectangle(BOX_X, BOX_Y, BOX_WIDTH, BOX_HEIGHT);
    DetectInput listener = new DetectInput();
    addMouseListener (listener);
  }

  // The purpose of paintComponent() is to "paint" the geometric figures that
  // we have in our panel.  It's analogous to paint() in an applet.
  // We need to call the generic JPanel paintComponent() first so that the
  // panel starts out clean.  Comment it out and see what happens!
  public void paintComponent(Graphics g)
  {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;
    g2.draw(box);
  }
}