Metalbird 의 좁은 새장

private String getBarcodeCheckBit(String barcodeNumber) {
   StringBuffer result = new StringBuffer();
   if (barcodeNumber.length() <= NORMAL_BARCODE_LENGTH) {
      for (int i = 0; i < NORMAL_BARCODE_LENGTH - barcodeNumber.length(); i++) {
         result.append("0");
      }
      result.append(barcodeNumber);
   }
   String barcode = result.toString();
   int s = 0;
   int d = 0;
   for (int i = 0; i < NORMAL_BARCODE_LENGTH - 1; i++) {
      if (i % 2 == 0) {
         s += Character.getNumericValue(barcode.charAt(i));
      } else {
         d += Character.getNumericValue(barcode.charAt(i)) * 3;
      }
   }

   int chk = (10 - ((s + d) % 10)) % 10;

   return String.valueOf(chk);
}