public class TestPassByRef
{
   public static void main( String [] args )
   {
      /* not supposed to work. Pass By Value */
      int i = 6;
      System.out.println( "intital primitive int: " + i );
      changeInt( i );
      System.out.println( "after method call: " + i );

      /* Doesn't work. Pass By Ref acts like Pass By Value*/
      Integer wrapperI = new Integer( 12 );
      System.out.println( "\ninital Wrapper value: " + wrapperI );
      changeInteger( wrapperI );
      System.out.println( "after method call: " + wrapperI );

      /* Doesn't work also. */
      AtomicInteger ai = new AtomicInteger( 24 );
      System.out.println( "\ninitial Atomic value: " + ai );
      changeAtomicInteger( ai );
      System.out.println( "after method call: " + ai );

      /* what should be done */
      int i2 = 30;
      System.out.println( "\ncorrect method primitive: " + i2 );
      i2 = changeInt( i2 ); //assign return value of method to original integer
      System.out.println( "after method call: " + i2 );

   }

   private static Integer changeInt( int i )
   {
      i = 100;
      System.out.println( "value returned by method call: " + i );
      return i;
   }

   private static Integer changeInteger( Integer i )
   {
      i = 100;
      System.out.println( "value returned by method call: " + i );
      return i;
   }

   private static AtomicInteger changeAtomicInteger( AtomicInteger i )
   {
      i = new AtomicInteger( 100 );
      System.out.println( "value returned by method call: " + i );
      return i;
   }

}

Monster m = new Monster( );
m.attack( new SwordSlash( ), badGuy );

public void attack( Attack a, Monster target )
   {
      if( a == null )
         return;

      System.out.println( "\n" + this.name + " used " + a.getName( ) + "!" );

      int damage = 0;
      if( a.getPower( ) != 0 )
         damage = calcDamage( a, target );

      target.takeDamage( damage );

      a.runEffect( target ); //AbstractMethodError
      a.decrementUsesLeft( );
      this.setAttackChoice( null );
   }

/* Nicholas Pickering
 * 2/7/2011 1:25 AM
 *
 * RacingCar.java
 *
 */

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

public class RacingCarFrame extends JFrame
{
   public RacingCarFrame( )
   {
      //panel to draw car onto. 
      ImagePanel car = new ImagePanel( );
      add( car );

      //KeyListener requires an object to accept the KeyEvents... I guess
      //I chose a textfield. 
      JTextField textfield = new JTextField( );
      textfield.addKeyListener( car.getKeyListener( ) );
      textfield.setFocusable( true );
      add( textfield, BorderLayout.SOUTH );
   }

   public static void main( String [] args )
   {
      RacingCarFrame frame = new RacingCarFrame( );
      frame.setTitle( "RacingCar" );
      frame.setSize( 400, 400 );
      frame.setLocationRelativeTo( null );
      frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
      frame.setVisible( true );
   }
}

class ImagePanel extends JPanel
{
   //timer for animation
   private Timer timer = new Timer( 10, new TimerListener( ) );

   //car's position
   int carX = 20;
   int carY = 40;

   //car's velocity;
   int carSpeed = 0;

   //car's dimensions
   int carBodyWidth = 50;
   int carBodyHeight = 10;
   int carHoodWidth = 10;
   int carHoodHeight = 10;
   int carTireHeight = 10;
   int carTireWidth = 10;

   //render frame
   public void paintComponent( Graphics g )
   {
      super.paintComponent( g );

      timer.start( );

      g.setColor( Color.GREEN );
      g.fillRect( carX, carY - 10, carBodyWidth, carBodyHeight );

      g.setColor( Color.GREEN.darker( ) );
      g.fillRect( carX + 20, carY - 20, carHoodWidth, carHoodHeight );

      g.setColor( Color.BLACK );
      g.fillOval( carX + 10, carY, carTireWidth, carTireHeight );
      g.fillOval( carX + 30, carY, carTireWidth, carTireHeight );
   }

   //causes car to move across screen without user interaction
   //carSpeed is currently set to 0, so it doesn't move.
   //setting carSpeed higher will causes it to drive
   //at a consistent speed across the frame. 
   private class TimerListener implements ActionListener
   {
      public void actionPerformed( ActionEvent ae )
      {
         carX += carSpeed;
         if( carX >= getWidth( ) )
            carX = 20;
         repaint( );
      }
   }

   //listens for keys and increases car's speed when SPACE is pressed 
   private class KeyHandler implements KeyListener
   {
      public void keyPressed( KeyEvent ke )
      {
         if( ke.getID( ) == KeyEvent.VK_SPACE )
         {
            carSpeed++;
            repaint( );
         }
         else
         {
            if( carSpeed > 0 )
               carSpeed--;
            repaint( );
         }
      }

      public void keyReleased( KeyEvent ke )
      {      }
      public void keyTyped( KeyEvent ke )
      {      }
   }

   //returns a KeyHandler object to the jFrame to accept key events
   public KeyHandler getKeyListener( )
   {
      return new KeyHandler( );
   }
}