@Override
    public void execute() {
        while (true) {
            showMessage();
            showCurrencies();
            try {
                moneyDialog.execute();
                currencyDialog.execute("Introduzca la divisa a convertir: ");
                this.calculate.execute();
            } catch (Exception ex) {
                if (ex.getMessage().equalsIgnoreCase("exit"))
                    this.exit.execute();
            }
        }
    }