com.keyoti.creditCard.logic
Class LuhnChecker

java.lang.Object
  |
  +--com.keyoti.creditCard.logic.LuhnChecker

public class LuhnChecker

extends Object

Checks for validity of a credit card NUMBER using Luhn algorithm (MOD10). Does NOT check for validity of a credit CARD. This means that this is mostly used for detecting typos and garbage input. Of course it can't tell you if the credit card number is associated to a valid account with money in it.

Author:

Keyoti

Constructor Summary

LuhnChecker()

Method Summary

static boolean	check(String cardNumber) Perform Luhn check.
static boolean	containsInvalidCharacters(String s) Checks if a String contains characters that are not valid in a credit card number.
static String	getDigitsOnly(String s) Filter out non-digit characters.
static boolean	isValid(String cardNumber) Perform Luhn & character validity check.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LuhnChecker

public LuhnChecker()

Method Detail

containsInvalidCharacters

public static boolean containsInvalidCharacters(String s)

Checks if a String contains characters that are not valid in a credit card number. Invalid characters are ANYTHING BUT digits (0-9), hyphens and whitespace.

Parameters:

s - the credit card number to check.

Returns:

true if there are invalid characters in the credit card number.

isValid

public static boolean isValid(String cardNumber)

Perform Luhn & character validity check.

Parameters:

cardNumber - String containing the card number to check.

Returns:

true if all characters in string are valid (digits, spaces, hyphens) AND conform to Luhn check.

check

public static boolean check(String cardNumber)

Perform Luhn check. Ignores any characters that are not digits.

Parameters:

cardNumber - String containing the card number to check.

Returns:

true if digits conform to Luhn check, false if not (including if string is devoid of digits)

getDigitsOnly

public static String getDigitsOnly(String s)

Filter out non-digit characters.

Parameters:

s - String to remove white space and hyphen chars from.