import java.util.concurrent.*;

public class CyclicBarrierEksempel {

    int tall, numThreads;
    Thread[] traader;
    CyclicBarrier bom;

    public CyclicBarrierEksempel(int numThreads) {

        this.numThreads = numThreads;
        bom = new CyclicBarrier(numThreads + 1);
        traader = new Thread[numThreads];

        for (int i = 0; i < 10; i++) {
            traader[i] = new Thread(new CyclicArbeider(i, bom, this));
            traader[i].start();
        }
    }

    public void settIgang() {
        tall = 10;
        for (int i = 9; i >= -1; i--) {
            try {
                bom.await();
                bom.await();
            } catch (Exception e) {
                e.printStackTrace();
            }
            tall = i;
        }
        tall = -1;

        try {
            bom.await();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("Alle tråder er ferdige.");
    }

    public int hentTall() {
        return tall;
    }

    public static void main(String[] args) {
        CyclicBarrierEksempel c = new CyclicBarrierEksempel(10);
        c.settIgang();
    }
}

class CyclicArbeider implements Runnable {
    int id;
    CyclicBarrier bom;
    CyclicBarrierEksempel cbe;

    public CyclicArbeider(int id, CyclicBarrier bom, CyclicBarrierEksempel cbe) {
        this.id = id;
        this.bom = bom;
        this.cbe = cbe;
    }

    @Override
    public void run() {

        int tall = 10;

        try {
            bom.await();
        } catch (Exception e) {
            e.printStackTrace();
        }

        while (tall != -1) {

            int resultat = tall * id;

            System.out.printf("%d ganger %d er lik %d.%n", tall, id, resultat);

            try {
                bom.await();
                bom.await();
            } catch (Exception e) {
                e.printStackTrace();
            }

            tall = cbe.hentTall();
        }
    }
}