static void traiterTransactions(BufferedReader reader) throws BibliothequeException,
    IOException {
        afficherAide();
        System.out.println("\n\n\n");
        String transaction = lireTransaction(reader);
        while(!finTransaction(transaction)) {
            // découpage de la transaction en mots
            final StringTokenizer tokenizer = new StringTokenizer(transaction,
                " ");
            if(tokenizer.hasMoreTokens()) {
                executerTransaction(tokenizer);
            }
            transaction = lireTransaction(reader);
        }
    }