public final class LuhnValidator extends Object
Luhn check digits are used, for example, by:
See Wikipedia for more details.
Constructor and Description |
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LuhnValidator() |
Modifier and Type | Method and Description |
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void |
initialize(A annotation) |
boolean |
isValid(String code,
javax.validation.ConstraintValidatorContext context) |
protected static int |
sumDigits(int number)
Add together the individual digits in a number.
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protected int |
toInt(char character,
int leftPos,
int rightPos)
Convert a character at a specified position to an integer value.
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protected int |
weightedValue(int charValue,
int leftPos,
int rightPos)
Calculates the weighted value of a charcter in the
code at a specified position.
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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.
charValue
- The numeric value of the characterleftPos
- The position of the character in the code, counting from left to rightrightPos
- The position of the character in the code, counting from right to leftException
public final void initialize(A annotation)
initialize
in interface javax.validation.ConstraintValidator<A extends Annotation,String>
public boolean isValid(String code, javax.validation.ConstraintValidatorContext context)
isValid
in interface javax.validation.ConstraintValidator<A extends Annotation,String>
protected int toInt(char character, int leftPos, int rightPos)
Note: this implementation only handlers numeric values For non-numeric characters, override this method to provide character-->integer conversion.
character
- The character to convertleftPos
- The position of the character in the code, counting from left to rightrightPos
- The positionof the character in the code, counting from right to leftprotected static int sumDigits(int number)
number
- The number whose digits are to be addedCopyright © 2010–2014 The Apache Software Foundation. All rights reserved.