// (c) F. Merciol 
// Plus d'informations sur http://m3101.merciol.fr
package thread;
public class Semaphore {

    private int value;

    public Semaphore (int value) {
				if (value < 0)
						throw new  IllegalArgumentException ("Negative value !");
				this.value = value;
    }

    public synchronized void p () {
				if (value <= 0)
						try {
								wait ();
						} catch (InterruptedException e) {
						}
				value--;
    }

    public synchronized void v () {
				value++;
				notify ();
    }
}