package ru.lionarius.sync;

public class MySemaphore {

    private final Object lock = new Object();
    private int permits;

    public MySemaphore(int permits) {
        this.permits = permits;
    }

    public void acquire() throws InterruptedException {
        synchronized (lock) {
            while (permits <= 0) {
                lock.wait();
            }

            permits--;
        }
    }

    public boolean tryAcquire() {
        synchronized (lock) {
            if (permits <= 0) {
                return false;
            }

            permits--;
            return true;
        }
    }

    public void release() {
        synchronized (lock) {
            permits++;
            lock.notify();
        }
    }

    public int availablePermits() {
        synchronized (lock) {
            return permits;
        }
    }
}