@Override
    public String toString() {
        final StringBuilder str = new StringBuilder();
        if (this.creditCardNumber != null) {
            str.append("CREDIT_CARD_NUMBER").append("=").append(this.creditCardNumber).append("\n");
        }
        if (this.expiryDate != null) {
            str.append("EXPIRY_DATE").append("=").append(this.expiryDate).append("\n");
        }
        if (this.cvv2 != null) {
            str.append("CVV2").append("=").append(this.cvv2).append("\n");
        }
        if (this.street != null) {
            str.append("STREET").append("=").append(this.street).append("\n");
        }
        if (this.zip != null) {
            str.append("ZIP").append("=").append(this.zip).append("\n");
        }
        if (this.secureCode != null) {
            str.append("SECURE_CODE").append("=").append(this.secureCode).append("\n");
        }
        return str.toString();
    }