ОС Лаб 3: "Basketball Tournament"

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

public class BasketballTournament {

    public static void main(String[] args) throws InterruptedException {
        Player.init();
        HashSet<Player> threads = new HashSet<>();
        for (int i = 0; i < 100; i++) {
            Player p = new Player();
            threads.add(p);
        }

        // run all threads in background
        for (Thread t : threads)
            t.start();
        // after all of them are started, wait each of them to finish for maximum 5_000 ms
        for (Thread t : threads)
            t.join(5000);


        // for each thread, terminate it if it is not finished
        boolean deadLock = false;
        for (Thread t : threads) {
            if (t.isAlive()) {
                deadLock = true;
                t.interrupt();
                System.out.println("Possible deadlock!");
            }
        }
        if (!deadLock)
            System.out.println("Tournament finished.");

    }
}

class Player extends Thread {
    static Semaphore basketballPlayer;
    static Semaphore enterDressingRoom;
    static Semaphore enterField;
    static Semaphore play;
    static Semaphore permitToPlay;
    static Semaphore permitToLeave;
    static Semaphore canBeginEntering;

    static Lock lock = new ReentrantLock();
    static int numPlayersInField = 0;

    static void init() {

        basketballPlayer = new Semaphore(20);
        enterDressingRoom = new Semaphore(10);
        enterField = new Semaphore(20);
        play = new Semaphore(1);
        permitToPlay = new Semaphore(0);
        permitToLeave = new Semaphore(0);

        // Let the next two teams get ready for the match while the previous two are playing
        canBeginEntering = new Semaphore(20);
    }

    public void execute() throws InterruptedException {
        // at most 20 players should print this in parallel
        basketballPlayer.acquire();
        System.out.println("Player inside.");

        // at most 10 players may enter in the dressing room in parallel
        enterDressingRoom.acquire();
        System.out.println("In dressing room.");
        Thread.sleep(10);// this represent the dressing time

        enterDressingRoom.release();

        canBeginEntering.acquire();

        enterField.acquire();

        lock.lock();
        numPlayersInField++;
        lock.unlock();

        if (numPlayersInField == 20) {
            play.acquire();
            permitToPlay.release(19);
        } else {
            permitToPlay.acquire();
        }

        System.out.println("Game started.");
        Thread.sleep(100);// this represent the game duration

        // only one player should print the next line, representing that the game has finished
        lock.lock();
        System.out.println("Player done.");
        numPlayersInField--;
        if (numPlayersInField == 0) {
            System.out.println("Game finished.");
            play.release();
            canBeginEntering.release(20);
        }
        lock.unlock();


        basketballPlayer.release();
        enterField.release();
    }

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