// concurrent/DiningPhilosophers.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// Hidden deadlock

// {ExcludeFromGradle} Gradle has trouble

import java.util.*;

import java.util.concurrent.*;

import onjava.Nap;

public class DiningPhilosophers {

private StickHolder[] sticks;

private Philosopher[] philosophers;

public DiningPhilosophers(int n) {

sticks = new StickHolder[n];

Arrays.setAll(sticks, i -> new StickHolder());

philosophers = new Philosopher[n];

Arrays.setAll(philosophers, i ->

new Philosopher(i,

sticks[i], sticks[(i + 1) % n])); // [1]

// Fix by reversing stick order for this one:

// philosophers[1] = // [2]

// new Philosopher(0, sticks[0], sticks[1]);

Arrays.stream(philosophers)

.forEach(CompletableFuture::runAsync); // [3]

}

public static void main(String[] args) {

// Returns right away:

new DiningPhilosophers(5); // [4]

// Keeps main() from exiting:

new Nap(3, "Shutdown");

}

}