Heading.java

package nasa.main;

import java.util.StringTokenizer;
import nasa.exceptions.InvalidInputException;
import nasa.exceptions.OutOfRangeException;

public class Heading {
 
 private int x;
 private int y;
 private byte direction;
 
 public Heading(){
 }
 
 public Heading(String position) throws InvalidInputException, OutOfRangeException{
  parse(position);
 }
 
 private void parse(String position) throws InvalidInputException, OutOfRangeException {
  StringTokenizer tokens = new StringTokenizer(position);
  if(tokens.hasMoreTokens()){
   try{
    x = Integer.parseInt(tokens.nextToken());
    y = Integer.parseInt(tokens.nextToken());
   }catch(NumberFormatException ne){
    throw new InvalidInputException("Invalid number!!");
   }
   direction = tokens.nextToken().getBytes()[0];
  }
  
  if(!verifyBounds()){
   throw new OutOfRangeException("Invalid inital position!!!");
  }
 }
 
 public void parseCommand(byte command) throws InvalidInputException, OutOfRangeException{
  switch(command){
  case Constants.ROTATE_LEFT:
   rotateLeft();
   break;
  case Constants.ROTATE_RIGHT:
   rotateRight();
   break;
  case Constants.MOVE:
   move();
   break;
  default:
   throw new InvalidInputException("Invalid signal");
  }
 }

 private void move() throws OutOfRangeException{
  switch (direction) {
  case Constants.DIRECTION_NORTH:
   y += 1;
   break;
  case Constants.DIRECTION_EAST:
   x += 1;
   break;
  case Constants.DIRECTION_SOUTH:
   y -= 1;
   break;
  case Constants.DIRECTION_WEST:
   x -= 1;
   break;
  }
  if(!verifyBounds()){
   throw new OutOfRangeException("Rover exceeding range!!!");
  }
 }

 private boolean verifyBounds() {
  if((x>ControlPanel.BOUNDS_X || y>ControlPanel.BOUNDS_Y)
    || x<0 || y<0){
   return false;
  }
  return true;
 }

 private void rotateRight() {
  switch(direction){
  case Constants.DIRECTION_NORTH:
   direction = Constants.DIRECTION_EAST;
   break;
  case Constants.DIRECTION_EAST:
   direction = Constants.DIRECTION_SOUTH;
   break;
  case Constants.DIRECTION_SOUTH:
   direction = Constants.DIRECTION_WEST;
   break;
  case Constants.DIRECTION_WEST:
   direction = Constants.DIRECTION_NORTH;
   break;
  }
 }

 private void rotateLeft() {
  switch(direction){
  case Constants.DIRECTION_NORTH:
   direction = Constants.DIRECTION_WEST;
   break;
  case Constants.DIRECTION_WEST:
   direction = Constants.DIRECTION_SOUTH;
   break;
  case Constants.DIRECTION_SOUTH:
   direction = Constants.DIRECTION_EAST;
   break;
  case Constants.DIRECTION_EAST:
   direction = Constants.DIRECTION_NORTH;
   break;
  }
 }

 public String toString(){
  String toString = null;
  toString = x+" "+y+" "+toChar(direction);
  return toString;
 }

 private char toChar(byte direction) {
  String s = String.valueOf(direction);
  char c = (char)Integer.parseInt(s);
  return c;
 }
}