import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

public class SemaphoreExample {
    public static void main(String[] args) {
        // Семафор с 2 разрешениями
        Semaphore semaphore = new Semaphore(2);

        // Пул из 5 потоков
        ExecutorService executor = Executors.newFixedThreadPool(5);

        for (int i = 0; i < 5; i++) {
            final int threadId = i;
            executor.submit(() -> {
                try {
                    System.out.println("Thread " + threadId + " is waiting for permit...");
                    semaphore.acquire(); // Получаем разрешение
                    System.out.println("Thread " + threadId + " acquired permit.");
                    Thread.sleep(2000); // Имитируем использование ресурса
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                } finally {
                    System.out.println("Thread " + threadId + " released permit.");
                    semaphore.release(); // Освобождаем разрешение
                }
            });
        }

        executor.shutdown();
    }
}