Java Event Handler Inner Class

// Demonstrate the key event handlers.
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;

class SimpleKey extends JTextArea {

  public SimpleKey() {
    addMouseListener(new MyMouseAdapter(this));
    addMouseMotionListener(new MyMouseMotionAdapter(this));
  }/*from  w ww. j  ava2  s. c o m*/

  class MyMouseAdapter extends MouseAdapter {
    SimpleKey adapterDemo;

    public MyMouseAdapter(SimpleKey adapterDemo) {
      this.adapterDemo = adapterDemo;
    }

    // Handle mouse clicked.
    public void mouseClicked(MouseEvent me) {
      adapterDemo.append("Mouse clicked");
    }
  }

  class MyMouseMotionAdapter extends MouseMotionAdapter {
    SimpleKey adapterDemo;

    public MyMouseMotionAdapter(SimpleKey adapterDemo) {
      this.adapterDemo = adapterDemo;
    }

    // Handle mouse dragged.
    public void mouseDragged(MouseEvent me) {
      adapterDemo.append("Mouse dragged");
    }
  }
}

public class Main {
  public static void main(String args[]) {
    // Create the frame on the event dispatching thread.
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        // Create a new JFrame container.
        JFrame jfrm = new JFrame("java2s.com");

        // Give the frame an initial size.
        jfrm.setSize(220, 200);

        // Terminate the program when the user closes the application.
        jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Add the label to the content pane.
        jfrm.add(new JScrollPane(new SimpleKey()));

        // Display the frame.
        jfrm.setVisible(true);

      }
    });
  }
}