public String format(Class<? extends Formatter> key, String message) {
        Validate.notNull(key, "Format class cannot be null!");
        Validate.notNull(message, "Message cannot be null!");
        Validate.notEmpty(message, "Message cannot be empty!");
        if (!formats.containsKey(key))
            return message;
        return formats.get(key).format(message);
    }