//: concurrency/DeadlockingDiningPhilosophers.java 
package concurrency;

import java.util.concurrent.*;

public class DeadlockingDiningPhilosophers {
  public static void main(String[] args) throws Exception {
    int ponder = 5;
    if(args.length > 0)
      ponder = Integer.parseInt(args[0]);
    int size = 5;
    if(args.length > 1)
      size = Integer.parseInt(args[1]);
    ExecutorService exec = Executors.newCachedThreadPool();
    Chopstick[] sticks = new Chopstick[size];
    LinkedBlockingQueue<Chopstick> bin = new LinkedBlockingQueue<Chopstick>();
    for(int i = 0; i < size; i++)
      sticks[i] = new Chopstick();
    for(int i = 0; i < size; i++)
        exec.execute(new Philosopher(
          sticks[i], sticks[(i+1) % size], bin, i, ponder));
    if(args.length == 3 && args[2].equals("timeout"))
      TimeUnit.SECONDS.sleep(5);
    else {
      System.out.println("Press 'Enter' to quit");
      System.in.read();
    }
    exec.shutdownNow();
  }
} 

//: concurrency/Philosopher.java
// A dining philosopher
package concurrency;

import java.util.concurrent.*;
import java.util.*;
import static util.Print.*;

public class Philosopher implements Runnable {
	private BlockingQueue<Chopstick> bin;
  private Chopstick left;
  private Chopstick right;
  private final int id;
  private final int ponderFactor;
  private Random rand = new Random(47);
  private void pause() throws InterruptedException {
    if(ponderFactor == 0) return;
    TimeUnit.MILLISECONDS.sleep(
      rand.nextInt(ponderFactor * 250));
  }
  public Philosopher(Chopstick left, Chopstick right, BlockingQueue<Chopstick> bin,
    int ident, int ponder) {
    this.left = left;
    this.right = right;
	this.bin = bin;
    id = ident;
    ponderFactor = ponder;
  }
  public void run() {
    try {
        print(this + " " + "thinking");
        pause();
        // Philosopher becomes hungry
        print(this + " " + "grabbing right");
        right.take();
        print(this + " " + "grabbing left");
        left.take();
        print(this + " " + "eating");
        pause();
        right.drop(); 
        left.drop();
		print("putting left to bin."); bin.put(left);
		while(!Thread.interrupted()) {
			print(this + " " + "thinking");
			pause();
			// Philosopher becomes hungry
			print(this + " " + "grabbing right from bin");
			right = bin.take();
			print(this + " " + "grabbing left from bin");
			left = bin.take();
			print(this + " " + "eating");
			pause();
			print(this + " " + "putting right to bin "); bin.put(right);
			print(this + " " + "putting left to bin "); bin.put(left);
		}
    } catch(InterruptedException e) {
      print(this + " " + "exiting via interrupt");
    }
  }
  public String toString() { return "Philosopher " + id; }
} ///:~

//: concurrency/Chopstick.java
package concurrency;

public class Chopstick {
  private boolean taken = false;
  public synchronized
  void take() throws InterruptedException {
    while(taken)
      wait();
    taken = true;
  }
  public synchronized void drop() {
    taken = false;
    notifyAll();
  }
} ///:~