package ch21concurrency.waxomatic;

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

/**
 * Basic task cooperation.
 * 
 * <pre>
 * Output: (95% match)
 * Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Exiting via interrupt
 * Ending Wax On task
 * Exiting via interrupt
 * Ending Wax Off task
 * </pre>
 */
class Car {
	private boolean waxOn = false;

	public synchronized void waxed() {
		waxOn = true; // Ready to buff
		notifyAll();
	}

	public synchronized void buffed() {
		waxOn = false; // Ready for another coat of wax
		notifyAll();
	}

	public synchronized void waitForWaxing() throws InterruptedException {
		while (waxOn == false)
			wait();
	}

	public synchronized void waitForBuffing() throws InterruptedException {
		while (waxOn == true)
			wait();
	}
}

class WaxOn implements Runnable {
	private Car car;

	public WaxOn(Car c) {
		car = c;
	}

	public void run() {
		try {
			while (!Thread.interrupted()) {
				printnb("Wax On! ");
				TimeUnit.MILLISECONDS.sleep(200);
				car.waxed();
				car.waitForBuffing();
			}
		} catch (InterruptedException e) {
			print("Exiting via interrupt");
		}
		print("Ending Wax On task");
	}
}

class WaxOff implements Runnable {
	private Car car;

	public WaxOff(Car c) {
		car = c;
	}

	public void run() {
		try {
			while (!Thread.interrupted()) {
				car.waitForWaxing();
				printnb("Wax Off! ");
				TimeUnit.MILLISECONDS.sleep(200);
				car.buffed();
			}
		} catch (InterruptedException e) {
			print("Exiting via interrupt");
		}
		print("Ending Wax Off task");
	}
}

public class D46_WaxOMatic {
	public static void main(String[] args) throws Exception {
		Car car = new Car();
		ExecutorService exec = Executors.newCachedThreadPool();
		exec.execute(new WaxOff(car));
		exec.execute(new WaxOn(car));
		TimeUnit.SECONDS.sleep(5); // Run for a while...
		exec.shutdownNow(); // Interrupt all tasks
	}
}