private void actionInterested (String key, OutputStream out) throws IOException {
	Object o = _hash.get(key);
	if (o != null){
	    Fichier f = (Fichier)o;
	    if (_estMisAssertion) 
		System.out.println("On me demande mon fichier " + key);
	    String reponse = "have " + key + " ";
	    int i;
	    boolean[] masque = f.getMasque();
	    for ( i=0 ; i<masque.length ; i++){
		if (masque[i])
		    reponse += "1";
		else
		    reponse += "0";
	    }
	    reponse += " ";
	    if (_estMisAssertion) 
		System.out.println(">> " + reponse);
	    out.write(reponse.getBytes());
	    out.flush();
	}
	else
	    System.out.println("Clé inexistante ...");
    }