LuhnValidator (Apache BVal :: Extras 3.0.1 API)

java.lang.Object
- org.apache.bval.extras.constraints.checkdigit.ModulusValidator<Luhn>
- - org.apache.bval.extras.constraints.checkdigit.LuhnValidator

All Implemented Interfaces:

jakarta.validation.ConstraintValidator<Luhn,CharSequence>
```
public final class LuhnValidator
extends ModulusValidator<Luhn>
```
Modulus 10 Luhn Check Digit calculation/validation.
Luhn check digits are used, for example, by:
- Credit Card Numbers
- IMEI Numbers - International Mobile Equipment Identity Numbers
Check digit calculation is based on modulus 10 with digits in an odd position (from right to left) being weighted 1 and even position digits being weighted 2 (weighted values greater than 9 have 9 subtracted).
See Wikipedia for more details.

Constructor Summary

Constructors
Constructor Description

LuhnValidator()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected int`	`weightedValue(int charValue, int leftPos, int rightPos)`	Calculates the weighted value of a charcter in the code at a specified position.

Methods inherited from class org.apache.bval.extras.constraints.checkdigit.ModulusValidator
initialize, isValid, sumDigits, toInt

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - LuhnValidator
```
public LuhnValidator()
```
- Method Detail
  - weightedValue
```
protected int weightedValue(int charValue,
                            int leftPos,
                            int rightPos)
                     throws Exception
```
    Calculates the weighted value of a charcter in the code at a specified position.
    
    For Luhn (from right to left) odd digits are weighted with a factor of one and even digits with a factor of two. Weighted values > 9, have 9 subtracted
    Calculates the weighted value of a character in the code at a specified position.
    Some modulus routines weight the value of a character depending on its position in the code (e.g. ISBN-10), while others use different weighting factors for odd/even positions (e.g. EAN or Luhn). Implement the appropriate mechanism required by overriding this method.
    
    Specified by:
    
    weightedValue in class ModulusValidator<Luhn>
    
    Parameters:
    
    charValue - The numeric value of the character
    
    leftPos - The position of the character in the code, counting from left to right
    
    rightPos - The position of the character in the code, counting from right to left
    
    Returns:
    
    The weighted value of the character
    
    Throws:
    
    Exception