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

public class Test {
    
    public static void main(String[] args) {
        
        Monitor m = new Monitor();
        Runnable k = new Kokk(m);
        Runnable s = new Servitor(m);

        Thread tk = new Thread(k);
        Thread ts = new Thread(s);
        tk.start();
        ts.start();
    }
}


class Kokk implements Runnable {

    private Monitor monitor;

    Kokk(Monitor m) {
        monitor = m;
    }

    @Override
    public void run() {
        for (int i =0 ; i < 10000; i++) {
            try {
                Thread.sleep(3000);
            monitor.settPaaBord("Hamburger.");
            } catch (InterruptedException e) {
                System.out.println(e);
            }
        } 
        System.out.println("Kokk ferdig");
    }

}

class Servitor implements Runnable {
    private Monitor monitor;

    Servitor(Monitor m) {
        monitor = m;
    }

    @Override
    public void run() {
        for (int i =0 ; i < 10000; i++) {
         System.out.println(monitor.hentTallerken());

        } 
        System.out.println("Servitor ferdig");
        
    }
}

class Monitor {
    private ArrayList<String> bord = new ArrayList<>();
    private ReentrantLock lock = new ReentrantLock();

    private Condition ikkeTom = lock.newCondition();

    void settPaaBord(String tallerken) {
        lock.lock();
        try {
            bord.add(tallerken);
            ikkeTom.signalAll();
        }
        finally {
            lock.unlock();
        }
    }

    public String hentTallerken() {
        lock.lock();
        try {
            while (bord.isEmpty()) {
                ikkeTom.await();
            }
            return bord.remove(0);
        }
        catch (InterruptedException e) {
            System.out.println(e);
        }
        finally {
            lock.unlock();
        }
        return "Tom tallerken.";
    }
}