// concurrent/StickHolder.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.

import java.util.concurrent.*;

public class StickHolder {

private static class Chopstick {}

private Chopstick stick = new Chopstick();

private BlockingQueue<Chopstick> holder =

new ArrayBlockingQueue<>(1);

public StickHolder() { putDown(); }

public void pickUp() {

try {

holder.take(); // Blocks if unavailable

} catch(InterruptedException e) {

throw new RuntimeException(e);

}

}

public void putDown() {

try {

holder.put(stick);

} catch(InterruptedException e) {

throw new RuntimeException(e);

}

}

}