import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

class Lines2 extends JComponent implements MouseInputListener {

  public static void main (String[] args) {
    JFrame gui = new JFrame ("Demo");
    gui.setContentPane (new Lines2 ());
    gui.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
    gui.pack ();
    gui.setVisible (true);
  }

  Lines2 () {
    lines = new ArrayList ();
    setPreferredSize (new Dimension (400, 400));
    addMouseListener (this); addMouseMotionListener (this);
    cx = cy = -1;
  }

  public synchronized void paintComponent (Graphics g) {
    g.setColor (Color.white);
    g.fillRect (0, 0, 400, 400);
    int x, y; x = y = 200;
    int i;
    for (i = 0; i < lines.size (); i += 1) {
      Point p = (Point) lines.get (i);
      g.setColor (new Color (i*217 % 255, i * 101 % 255, i * 17 % 255));
      g.drawLine (x, y, p.x, p.y);
      x = p.x; y = p.y;
    }
    if (cx != -1 && cy != -1) {
      g.setColor (new Color (i*217 % 255, i * 101 % 255, i * 17 % 255));
      g.drawLine (x, y, cx, cy);
    }
  }

  private java.util.List lines;
  private int cx, cy;

  synchronized void add (int x, int y) {
    lines.add (new Point (x, y));
    repaint ();
  }

  public void mouseClicked (MouseEvent e) {
    add (e.getX (), e.getY ());
  }
  public void mouseMoved (MouseEvent e) {
    cx = e.getX (); cy = e.getY (); repaint ();
  }

  public void mouseEntered (MouseEvent e) { }
  public void mouseExited (MouseEvent e) { cx = cy = -1; repaint (); }
  public void mousePressed (MouseEvent e) { }
  public void mouseReleased (MouseEvent e) { }
  public void mouseDragged (MouseEvent e) { }


}