Toy Robot in Java 8

robots.java

package com.mikerowecode.robot8;

import java.util.Scanner;
import java.util.StringTokenizer;
import java.util.function.Function;

public class Robots {
    public static void main(String[] args) {
        Robot robot = new Robot(-1, -1, Direction.WEST);
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            robot = Commands.fromString(in.nextLine()).apply(robot);
        }
    }
}

enum Direction {
    NORTH, EAST, SOUTH, WEST;
    public Direction left() { return values()[((ordinal() + 3) % values().length)]; }
    public Direction right() { return values()[((ordinal() + 1) % values().length)]; }
}

class Commands {

    public static Function<Robot, Robot> fromString(String s) {
        StringTokenizer tokenizer = new StringTokenizer(s);
        String c = tokenizer.nextToken();
        if ("PLACE".equals(c)) {
            if (tokenizer.hasMoreTokens()) {
                String[] v = tokenizer.nextToken().split(",");
                try {
                    Integer x = Integer.valueOf(v[0]);
                    Integer y = Integer.valueOf(v[1]);
                    Direction f = Direction.valueOf(v[2]);
                    return robot -> new Robot(x, y, f);
                } catch (Exception e) {
                    // fall through
                }
            }
        }

        if ("MOVE".equals(c)) return robot -> {
            if (robot.onTable()) {
                Robot schrodingerRobot = null;
                switch (robot.facing) {
                    case NORTH:
                        schrodingerRobot = new Robot(robot.x, robot.y + 1, robot.facing);
                        break;
                    case SOUTH:
                        schrodingerRobot = new Robot(robot.x, robot.y - 1, robot.facing);
                        break;
                    case EAST:
                        schrodingerRobot = new Robot(robot.x + 1, robot.y, robot.facing);
                        break;
                    case WEST:
                        schrodingerRobot = new Robot(robot.x + 1, robot.y, robot.facing);
                        break;
                }
                if (schrodingerRobot.onTable()) return schrodingerRobot;
            }
            return robot;
        };
        if ("LEFT".equals(c)) return robot -> new Robot(robot.x, robot.y, robot.facing.left());
        if ("RIGHT".equals(c)) return robot -> new Robot(robot.x, robot.y, robot.facing.right());
        if ("REPORT".equals(c)) return robot -> {
            System.out.printf("%d,%d,%s\n", robot.x, robot.y, robot.facing);
            return robot;
        };
        // default to noop
        return robot -> robot;
    }
}

class Robot {

    public static final int HEIGHT = 5;
    public static final int WIDTH = 5;

    public final int x;
    public final int y;
    public final Direction facing;

    public Robot(int x, int y, Direction facing) {
        this.x = x;
        this.y = y;
        this.facing = facing;
    }

    public boolean onTable() {
        return x >= 0 && x < WIDTH && y >= 0 && y < HEIGHT;
    }
}