import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.Condition;


public class RaceCondition1 {
	public static void main(String[] args) {
		
		// PannekakeStabel er en MONITOR!
		PannekakeStabel pannekakestabel = new PannekakeStabel();

		// Lage ny kokk:
		(new Thread(new Kokk(pannekakestabel))).start();

		// Lager nye personer
		for (int i = 0; i < 50; i++) {
			(new Thread(new Person(pannekakestabel))).start();
		}

	}
}

class Person implements Runnable {

	static int IDCounter = 1;
	private int minID;

	PannekakeStabel pannekakestabel;

	// Bruker konstrukt?r til ? sette monitor (pannekakestabel)
	public Person(PannekakeStabel pannekakestabel) {
		minID = IDCounter ++;
		this.pannekakestabel = pannekakestabel;
	}

	// Hent en pannekake.
	public void run() {
		//System.out.println("Hei " + minID);
		System.out.println("Person " + minID + " henter en pannekake");
		pannekakestabel.hentEnPannekake();
		System.out.println("Person " + minID + " har hentet en pannekake");
	}
}

class Kokk implements Runnable {

	private PannekakeStabel pannekakestabel;

	public Kokk(PannekakeStabel pannekakestabel) {
		this.pannekakestabel = pannekakestabel;
	}

	public void run() {

		for (int i = 0; i < 50; i ++) {
			System.out.println("Kokken lager en ny pannekake!");
			pannekakestabel.settInnPannekake();

			try {
				Thread.sleep(1500);
			} catch (Exception e) {

			}
		}
	}

}

class PannekakeStabel {

	private final Lock lock = new ReentrantLock();
	private final Condition erTom = lock.newCondition();


	int antallPannekaker = 0;

	public void settInnPannekake() {
		lock.lock();

		try {

			antallPannekaker ++;
			erTom.signal();
		} 
		finally {
			lock.unlock();
		}


	}

	public int hentEnPannekake() {
		lock.lock(); // 1: L?s l?sen

		try { // 2: Pr?v ? gj?re masse rart.

			while (antallPannekaker <= 0) {
				erTom.await();
			}

			System.out.println(antallPannekaker);
		

			// KODE

			return antallPannekaker --;

		// 3: finally, l?s opp!
		} catch (InterruptedException ie) {
			System.out.println(ie);
			return -1;
		} catch (Exception e) {
			// await()
			return -1;
		} finally {
			lock.unlock();
		}
	}
}