class CardTokenRequest implements Serializable {

    public String getString() {
        try {
            Gson gson = new Gson();
            return gson.toJson(this);
        } catch (NullPointerException e) {
            e.printStackTrace();
            return "";
        }
    }

    public  CardTokenRequest();
    public  CardTokenRequest(String cardNumber, String cardCVV,
                            String cardExpiryMonth, String cardExpiryYear, String clientKey);

}