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

public class Main {
    public static void main(String[] args) {
        TellerBeholder teller = new TellerBeholder();
        Runnable task = new MyTask(teller);
        Thread worker1 = new Thread(task);
        Thread worker2 = new Thread(task);
        worker1.start();
        worker2.start();

        try {
            worker1.join();
            worker2.join();
        } catch (InterruptedException e) {
            System.out.println("Traad ble avbrutt");
            return;
        }

        System.out.println("Alt er ferdig");
    }
}

class MyTask implements Runnable {
    private TellerBeholder teller;

    public MyTask(TellerBeholder teller) {
        this.teller = teller;
    }

    public void run() {
        System.out.println("Starting! Shared counter = " + teller.hentTeller());
        for (int i = 0; i < 10000; i++) {
            teller.oekTeller();
        }
        System.out.println("Done! Shared counter = " + teller.hentTeller());
    }
}


class TellerBeholder {
    private Lock laas = new ReentrantLock();
    private int sharedCounter = 0;

    public void oekTeller() {
        laas.lock();
        try {
            sharedCounter += 1;
        } finally {
            laas.unlock();
        }
    }

    public int hentTeller() {
        return sharedCounter;
    }
}