ОС - Volleyball

//https://github.com/finki-mk/OS/tree/master/synchronization/src/main/java/mk/ukim/finki/os/synchronization/exam19/s2

package ispiti.volleyballTournament;

import java.time.LocalDateTime;
import java.util.HashSet;
import java.util.concurrent.Semaphore;
import java.util.concurrent.locks.Lock;

public class VolleyballTournament {

    public static void main(String[] args) throws InterruptedException {
        HashSet<Player> threads = new HashSet<>();
        for (int i = 0; i < 60; i++) {
            Player p = new Player();
            threads.add(p);
        }
        init();
        for(Thread t:threads){
            t.start();
        }

        for(Thread t:threads){
            t.join();
        }
        System.out.println("Tournament finished.");
    }

    public static void init(){
        Locks.canEnter = new Semaphore(12);
        Locks.enterGarderober = new Semaphore(4);
        Locks.doneChanging = new Semaphore(0);
        Locks.startGame = new Semaphore(0);
        Locks.gameFinished = new Semaphore(0);
    }
}

class Locks{
    static Semaphore canEnter;
    static Semaphore enterGarderober;
    static int players = 0;
    static Semaphore doneChanging;
    static Semaphore startGame;
    static Semaphore gameFinished;
    static int playersChanging = 0;
}
class Player extends Thread{

    public void execute() throws InterruptedException {
       Locks.canEnter.acquire(); //maksimum 12 igraci smeat da bidat prisutni
       System.out.println("Player inside.");

       Locks.enterGarderober.acquire(); //samo 4ca smeat da se vo garderoberot
       synchronized (Player.class){
            Locks.playersChanging++; //zgolemuvame kolku se vo garderoberot
       }
       System.out.println("In dressing room.");
       Thread.sleep(10);// se presoblekuvaat
       if(Locks.playersChanging == 4){
           //ako e ova posledniot
           Locks.playersChanging = 0;
           Locks.enterGarderober.release(4); //ozdava dozvola da vlezat ushte 4
       }
       Locks.doneChanging.release(); //zavrsile so presoblekuvanje

        synchronized (Player.class){
            Locks.players++;
        }

        boolean controller = false;
        if(Locks.players == 12){ //posledniot ke bide kontrolerot
            controller = true;
            Locks.enterGarderober.acquire(4);
            Locks.doneChanging.acquire(12); //gi ceka site
            Locks.startGame.release(12); //dava dozvola da pocnat
        }

        Locks.startGame.acquire();
        System.out.println("Game started.");
        Thread.sleep(100);// this represent the game duration
        System.out.println("Player done.");
        Locks.gameFinished.release();
        if(controller) {
            Locks.gameFinished.acquire(12);
            System.out.println("Game finished.");
            Locks.players = 0;
            Locks.playersChanging = 0;
            Locks.canEnter.release(12);
            Locks.enterGarderober.release(4);
        }
    }

    @Override
    public void run() {
        try {
            execute();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}