[Chapter 7] 7.4 Scribbling in Java 1.1

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| Chapter 7 Events |

## 7.4 Scribbling in Java 1.1

The Java 1.1 event model is quite flexible, and, as we'll see, there are several different ways you can use it to structure your event-handling code. Example 7.2 shows the first technique. Once again, this is our basic `Scribble` applet, this time using the Java 1.1 event model. This version of the applet implements the `MouseListener` and `MouseMotionListener` interfaces itself, and registers itself with its own `addMouseListener()` and `addMouseMotionListener()` methods.

#### Example 7.2: Scribble: Implementing the Listener Interfaces Directly

    import java.applet.*;
    import java.awt.*;
    import java.awt.event.*;
    public class Scribble2 extends Applet
                          implements MouseListener,  MouseMotionListener {
      private int last_x, last_y;
      public void init() {
        // Tell this applet what MouseListener and MouseMotionListener
        // objects to notify when mouse and mouse motion events occur.
        // Since we implement the interfaces ourself, our own methods are called.
        this.addMouseListener(this);
        this.addMouseMotionListener(this);
      }
      // A method from the MouseListener interface.  Invoked when the
      // user presses a mouse button.
      public void mousePressed(MouseEvent e) {
        last_x = e.getX();
        last_y = e.getY();
      }
      // A method from the MouseMotionListener interface.  Invoked when the
      // user drags the mouse with a button pressed.
      public void mouseDragged(MouseEvent e) {
        Graphics g = this.getGraphics();
        int x = e.getX(), y = e.getY();
        g.drawLine(last_x, last_y, x, y);
        last_x = x; last_y = y;
      }
      // The other, unused methods of the MouseListener interface.
      public void mouseReleased(MouseEvent e) {;}
      public void mouseClicked(MouseEvent e) {;}
      public void mouseEntered(MouseEvent e) {;}
      public void mouseExited(MouseEvent e) {;}
      // The other method of the MouseMotionListener interface.
      public void mouseMoved(MouseEvent e) {;}
    }

The Java 1.1 Event Model |  | Scribbling with Inner Classes