package misc;

import java.util.Random;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

public class RobotCoin {

public static final int SIZE = 10000;

public static Boolean[] coins = new Boolean[SIZE];

static {

boolean standard = false;

for (int i = 0; i < SIZE; i++) {

coins[i] = standard;

standard = !standard;

}

}

public static void main(String[] args) throws InterruptedException {

int poolSize = 10;

ExecutorService es = Executors.newFixedThreadPool(poolSize);

for (int i = 0; i < poolSize; i++) {

es.execute(new Robot());

}

Thread.sleep(10000);

es.shutdownNow();

// check true/false distribution

int trueCoins = 0;

for (int i = 0; i < coins.length; i++) {

if (coins[i]) {

trueCoins++;

}

}

System.out.println("True Coins: " + trueCoins);

}

}

class Robot implements Runnable {

private Random rnd = new Random();

@Override

public void run() {

while (!Thread.currentThread().isInterrupted()) {

int coinNum = rnd.nextInt(RobotCoin.SIZE);

synchronized (RobotCoin.coins[coinNum]) {

if (RobotCoin.coins[coinNum] == false) {

boolean next = rnd.nextBoolean();

RobotCoin.coins[coinNum] = next;

System.out.println(Thread.currentThread().getName()

+ ": Coin " + coinNum + "false -> " + next);

} else {

RobotCoin.coins[coinNum] = false;

System.out.println(Thread.currentThread().getName()

+ ": Coin " + coinNum + "true -> false");

}

}

Thread.yield();

}

}

}