import java.awt.geom.Point2D;
import java.awt.geom.Ellipse2D;
import java.awt.Graphics2D;
import java.util.ArrayList;

/**
   This class draws a cloud of circles
*/
public class Cloud
{
   /**
      Construct a Cloud object
   */
   public Cloud()
   {
      points = new ArrayList();
   }
   
   /**
      Add a point to the array list
      @param aPoint the point to add
   */
   public void add(Point2D.Double aPoint)
   {
      points.add(aPoint);
   }
   
   /**
      Draws the cloud
      @param g2 the graphics context
   */
   public void draw(Graphics2D g2)
   {
      for (int i = 0; i < points.size(); i++)
      {
         Point2D.Double p = (Point2D.Double)points.get(i);
         
         Ellipse2D.Double e =
            new Ellipse2D.Double(p.getX(), p.getY(), RADIUS, RADIUS);         
            
         g2.draw(e);
      }
   }
   
   private ArrayList points;
   private final int RADIUS = 5;
}

/* Class Cloud:
1. Constructor creates an array list.
2. The method add takes a Point2D.Double as an argument and it adds it to the array list.
3. The method draw creates the points and uses g2.draw(aPoint). Note: a Point2D.Double can not be drawn. So, you should draw an Ellipse2D.Double with x and y from Point2D.Double.
4. Write a class that extends Applet or JApplet to draw a cloud's points by creating an object of Cloud and randomly generating the x and y coordinates. */

import javax.swing.JApplet;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Random;
import java.awt.geom.Point2D;

/**
   This applet displays a cloud of circles
*/
public class ExP13_7JApplet extends JApplet
{
   public void paint(Graphics g)
   {
      Graphics2D g2 = (Graphics2D)g;

      Cloud c = new Cloud();
      
      Random generator = new Random();
      double x = 0;
      double y = 0;
      
      for (int i = 0; i < 20; i++)
      {
         x = 200 * generator.nextDouble();
         y = 200 * generator.nextDouble();         
         c.add(new Point2D.Double(x, y));
      }
      
      c.draw(g2);
   }
}