package fr.umlv.conc;

import java.util.Arrays;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.IntStream;

public class PhilosopherDinner {
  private final ReentrantLock[] forks;
  
  public PhilosopherDinner(int forkCount) {
    ReentrantLock[] forks = new ReentrantLock[forkCount];
    Arrays.setAll(forks, i -> new ReentrantLock());
    this.forks = forks;
  }
  
  public void eat(int index) {
    ReentrantLock fork1 = forks[index];
    ReentrantLock fork2 = forks[(index + 1) % forks.length];
    fork1.lock();
    try {
      fork2.lock();
      try {
        System.out.println("philosopher " + index + " eat");
      } finally {
        fork2.unlock();
      }
    } finally {
      fork1.unlock();
    }
  }
  
  public static void main(String[] args) {
    PhilosopherDinner dinner = new PhilosopherDinner(5);
    IntStream.range(0, 5).forEach(i -> {
      new Thread(() -> {
        for(;;) {
          dinner.eat(i);
        }
      }).start();
    });
  }
}