Dining Philo | SO

import java.util.*;
import java.io.IOException;

public class DiningPhilosophersUsingMonitor {
    private static int NUMPHILOSOPHERS = 0;

    static Scanner input = new Scanner(System.in);
    public static void main (String[] args) {
        try {
            System.out.println(" ============== Dining Philosophers ==============");
            System.out.print(" Jumlah philosopher : "); NUMPHILOSOPHERS = input.nextInt();
            System.out.println(" =================================================");
            System.out.println(" ! Tekan Enter untuk berhenti saat proses!\n");

            Philosopher5[] philosophers = new Philosopher5[NUMPHILOSOPHERS];
            PhilosopherMonitor monitor = new PhilosopherMonitor(NUMPHILOSOPHERS);

            for (int i = 0; i < NUMPHILOSOPHERS; i++) {
                philosophers[i] = new Philosopher5(i, monitor);
                new Thread(philosophers[i]).start();
            }

            System.in.read();
            System.exit(0);
        } catch (IOException ex) {}
    }

}

class Philosopher5 implements Runnable {
    private Random numGenerator = new Random();
    private int id;
    private PhilosopherMonitor monitor;

    public Philosopher5 (int id, PhilosopherMonitor monitor) {
        this.id = id;
        this.monitor = monitor;
    }
    public void run() {
        try {
            while (true) {
                think();
                monitor.pickUpChopsticks(id);
                eat();
                monitor.putDownChopsticks(id);
            }
        } catch (InterruptedException e) {
            System.out.println(" x Philosopher " + id + " diganggu");
        }
    }
    private void think() throws InterruptedException {
        System.out.println(" ! Philosopher " + id + " berpikir");
        System.out.flush();
        Thread.sleep (1000);
    }
    private void eat() throws InterruptedException {
        Thread.sleep (1000);
    }

}

class PhilosopherMonitor {
    private enum State {THINKING, HUNGRY, EATING};
    private State[] philosopherState;

    public PhilosopherMonitor (int numPhilosophers) {
        philosopherState = new State[numPhilosophers];
        for (int i = 0; i < philosopherState.length; i++) {
            philosopherState[i] = State.THINKING;
        }
    }
    public synchronized void pickUpChopsticks(int philosopherId) throws InterruptedException {
        philosopherState[philosopherId] = State.HUNGRY;
        System.out.println(" + Philosopher " + philosopherId + " lapar");
        System.out.flush();

        while (someNeighborIsEating(philosopherId)) {
            wait();
        }

        philosopherState[philosopherId] = State.EATING;
        System.out.println(" - Philosopher " + philosopherId + " makan");
        System.out.flush();
    }
    private boolean someNeighborIsEating(int philosopherId) {
        if (philosopherState[(philosopherId + 1) % philosopherState.length] == State.EATING){
            return true;
        }
        if (philosopherState[(philosopherId + philosopherState.length - 1) % philosopherState.length] == State.EATING){
            return true;
        }
        return false;
    }
    public synchronized void putDownChopsticks(int philosopherId) {
        philosopherState[philosopherId] = State.THINKING;
        notifyAll();
    }
}