//
// FILE:     MultiBallWorldFrame.java
// AUTHOR:   Eugene Wallingford 
// DATE:     2012/10/11
// COMMENT:  a frame with a bunch of moving balls and a button
//           that causes the balls to move
//
// MODIFIED: 2012/10/11 -- Eugene Wallingford
// CHANGE:   changed the button to be a toggle switch that turns
//           ball movement on and off
//

import java.awt.Button;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class MultiBallWorldFrame extends Frame
{
  private static final int FrameWidth  =  600;
  private static final int FrameHeight =  400;
  private static final int Iterations  = 2000;

  private Ball[]  ball;
  private int     counter;
  private boolean ballsAreMoving;        // new

  public MultiBallWorldFrame( int numberOfBalls )
  {
    super();
    
    setSize ( FrameWidth, FrameHeight );
    setTitle( "Multi Ball World" );
    
    ball = new Ball[numberOfBalls];
    for (int i = 0; i < numberOfBalls; i++)
    {
      int dx = (int) (20 * Math.random() );
      int dy = (int) (10 * Math.random() );
      ball[i] = new BoundedBall( 100, 100, 10, dx, dy, this );
    }

    counter = 0;
    ballsAreMoving = false;            // new
    
    /*
     * This is the new code to add our button
     */
    Button move = new Button( "move" );
    move.addActionListener( new MoveButtonListener() );
    add( "South", move );
  }

  public void paint( Graphics g )
  {
    for (int i = 0; i < ball.length; i++)
    {
      ball[i].paint( g );
      if ( ballsAreMoving )   // now the program cause balls to move again,
        ball[i].move();       // but only if the switch is "on"
    }
    counter++;
    
    if ( counter >= Iterations )
      System.exit( 0 );
    repaint();
  }

  /* -------------- inner classes -------------- */

  private class MoveButtonListener implements ActionListener
  {
    public void actionPerformed( ActionEvent e )
    {
      ballsAreMoving = !ballsAreMoving;        // new
    }
  }
}