design a state machine for this code

MarsRover.java

import java.util.Scanner;

public class MarsRover {

private String inst_set;

private Plateau p;

private Cell currentLocation;

public enum Direction{N,S,E,W}

Direction dir;

public MarsRover(Plateau p1, int x, int y, Direction dir, String instSet) {

p=p1;

inst_set=instSet;

this.dir=dir;

currentLocation=new Cell(x, y);

}

public MarsRover(){}

private void executeInst() {

int i = 0;

while (i < inst_set.length()) {

char inst = inst_set.charAt(i++); //get each inst separately as a character

if (inst == 'M') {

Cell nextCell = p.getNeighbour(dir, currentLocation);

if (nextCell != null)

currentLocation = nextCell;

else

System.out.println("This move is not possible. Going to next Instruction");

}

if (inst == 'L' || inst == 'R') {

dir = setDirection(dir, inst);

}

}

}

public void showCurrentLocation(){

System.out.println("Current Cell is:");

System.out.print(currentLocation.x);

System.out.print("\t"+currentLocation.y);

System.out.print("\t"+dir+" ");

}

public Direction setDirection(Direction dir, char inst) {

if(inst=='L') {

switch (dir) {

case N:

dir = Direction.W;

break;

case W:

dir = Direction.S;

break;

case S:

dir = Direction.E;

break;

case E:

dir = Direction.N;

break;

}

}

else if(inst=='R'){

switch (dir) {

case N:

dir = Direction.E;

break;

case W:

dir = Direction.N;

break;

case S:

dir = Direction.W;

break;

case E:

dir = Direction.S;

break;

}

}

return dir;

}

public static void main(String... a){

Plateau p1=new Plateau();

Scanner in = new Scanner(System.in);

int x,y;

String instSet;

String dir;

System.out.println("Enter the direction the rover is Headed");

dir=in.nextLine();

System.out.println("Enter the Initial XLocation:");

x=in.nextInt();

in.nextLine();

System.out.println("Enter the Initial YLocation:");

y=in.nextInt();

in.nextLine();

System.out.println("Enter the Instructions\t");

instSet=in.nextLine();

MarsRover mr1=new MarsRover(p1,x,y,Direction.valueOf(dir),instSet);

mr1.executeInst();

mr1.showCurrentLocation();

}

}

Plateau.java

import java.util.Scanner;

class Plateau {

private int size;

public Plateau() {

Scanner in = new Scanner(System.in);

System.out.println("Enter the Size of the plateau");

size=in.nextInt();

in.nextLine();

}

public Plateau(int sz){

size=sz;

}

public Cell getNeighbour(MarsRover.Direction dir,Cell c){

Cell neighbour = null;

switch (dir) {

case N:

neighbour=new Cell(c.x,c.y+1);

break;

case W:

neighbour=new Cell(c.x-1,c.y);

break;

case S:

neighbour=new Cell(c.x,c.y-1);

break;

case E:

neighbour=new Cell(c.x+1,c.y);

break;

}

if((neighbour.x>=0)&&(neighbour.y>=0)&&(neighbour.x

return neighbour;

return null;

}

}

Cell.java

class Cell{

int x;

int y;

public Cell(int PosX, int PosY) {

x=PosX;

y=PosY;

}

}