// this is the basics of gui stuff
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;

public class J06Animation extends Component implements Runnable
{
  private ArrayList<Point> points;
  private JFrame mainFrame;

  // this is called a constructor (look up the term)
  public J06Animation()
  {
    points = new ArrayList<Point>();
    points.add(new Point(5,5));
    points.add(new Point(20,20));

    mainFrame = new JFrame();

    mainFrame.getContentPane().setLayout(new FlowLayout());
    mainFrame.getContentPane().add(this);
    mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    mainFrame.pack();
    mainFrame.setVisible(true);
  }

  public static void main(String[] args)
  {
    J06Animation j06 = new J06Animation();
    Thread t = new Thread(j06);
    t.start();
  }	
  
  public void run()
  {
    while(mainFrame.isVisible())
    {
      try{
	points.add(new Point((int)(Math.random()*400),(int)(Math.random()*400)));
	this.repaint();
	Thread.sleep(1000);
      }catch(Exception e){}
    }
  }

  public Dimension getPreferredSize() 
  {
    return new Dimension(400,400);
  }

  public void paint(Graphics g)
  {
    g.setColor(Color.BLACK);
    g.fillRect(0,0,400,400);
    
    for(int i=0;i<points.size()-1;i++)
    {
      g.setColor(new Color((float)Math.random(),(float)Math.random(),(float)Math.random()));
      g.drawLine(points.get(i).x,points.get(i).y,points.get(i+1).x,points.get(i+1).y);
    }

    g.setColor(Color.RED);
    // note the two types of loop
    for(Point p : points)
    {
      g.drawLine(p.x,p.y,p.x,p.y);
    }
  }
}