I have string with any text. It can be like this - "abcdef 123456789521 zxcvb"
, and - "45651256"
, and - "asdad 564654 sddsf 4"
. I want to search in text PAN number, that can be different length, and than verify it with luhn
algorithm. I know, that I can to find it by regx, but it require expresion like this - "Pattern.compile("[A-Z]{5}[0-9]{4}[A-Z]{1}");
. But I don't know how many characters and digits and in what order my string will contains. May be anyone know how to do it? Any advice?
I assume that by PAN you mean credit card number (see PAN on wikipedia).
According to that article, the numbers must be between 8 and 19 digits long. Thus, you search your text for numbers with a length in that interval, store them and check them with the Luhn algorithm. Here's an implementation that finds numbers between 8-19 digits in length and performs the Luhn-check:
import java.util.ArrayList;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class main {
public static void main(String[] args) {
String text = "helloWor4712389062l648977135536d 239012390oife234923 uiwed wq12893129038";
ArrayList<String> result = getPossiblePANs(text);
for(String pan : result) {
System.out.print("Possible PAN: " + pan);
if(luhnCheck(pan))
System.out.println(" is valid!");
else
System.out.println(" is INVALID!");
}
}
static ArrayList<String> getPossiblePANs(String text){ //Numbers w. 8-19 digits
ArrayList<String> res = new ArrayList<>();
Pattern p = Pattern.compile("\\d{8,19}+");
Matcher m = p.matcher(text);
while(m.find())
res.add(m.group());
return res;
}
static boolean luhnCheck(String cardNumber){
if(cardNumber.length() < 8 || cardNumber.length() > 19)
return false;
int sum = 0;
int begin = cardNumber.length() - 2;
for(int i = begin; i >= 0; i-=2){
int number = Integer.parseInt(cardNumber.substring(i, i+1)) * 2;
if(number > 9) sum += (number - 9);
else sum += number;
}
return (sum % 10) == 0;
}
}
Possible PAN: 4712389062 is INVALID!
Possible PAN: 648977135536 is INVALID!
Possible PAN: 239012390 is INVALID!
Possible PAN: 12893129038 is valid!