$/**$

This class models a ball that bounces off walls.

$*/$

public class Ball

$\{$

$//$ Instance variables

private int distance;

private int startPosition;

private int position;

private boolean travelingEast;

private boolean travelingWest;

$/**$

Constructs a ball at position $0$ traveling east.

@param rightWall the position of the wall to the right

$*/$

public Ball$($int rightWall$)$

$\{$

distance$=$rightWall;

position$=0$;

travelingEast$=$true;

travelingWest$=$false;

$\}$

$/**$

Moves the ball.

$*/$

public void move$()$

$\{$if$($travelingEast && position distance$)$

$\{$travelingEast$=$false;

travelingWest $=$ true;$\}$

$\}$

if$($travelingWest && position$>0)$

$\{$position$=$ position $-1$;

if $($startPosition$<0)$

$\{$travelingEast$=$true;

travelingWest $=$ false;$\}$

$\}$

$\}$

$/**$

Gets the current position.

@return the current position

$*/$

public int getPosition$()$

$\{$

return position;

$\}$

$\}$