Package org.apache.bval.extras.constraints.checkdigit

Class ISBN10Validator

java.lang.Object

org.apache.bval.extras.constraints.checkdigit.ISBN10Validator

All Implemented Interfaces:

javax.validation.ConstraintValidator<ISBN10,CharSequence>

public final class ISBN10Validator
extends Object

Modulus 11 ISBN-10 Check Digit calculation/validation.

ISBN-10 Numbers are a numeric code except for the last (check) digit which can have a value of "X".

Check digit calculation is based on modulus 11 with digits being weighted based by their position, from right to left with the first digit being weighted 1, the second 2 and so on. If the check digit is calculated as "10" it is converted to "X".

N.B. From 1st January 2007 the book industry will start to use a new 13 digit ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC (see EAN13CheckDigit) standard.

For further information see:

• Wikipedia - International Standard Book Number (ISBN).
• ISBN-13 Transition details.

Constructor Summary

Constructors

Constructor	Description
ISBN10Validator()

Method Summary

Modifier and Type	Method	Description
void	initialize(A annotation)
boolean	isValid(CharSequence code, javax.validation.ConstraintValidatorContext context)
protected static int	sumDigits(int number)	Add together the individual digits in a number.
protected int	toInt(char character, int leftPos, int rightPos)	Convert a character at a specified position to an integer value.
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 java.lang.Object

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

Constructor Detail

ISBN10Validator

public ISBN10Validator()

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 ISBN-10 (from right to left) digits are weighted by their position.

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.

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

toInt

protected int toInt(char character,
                    int leftPos,
                    int rightPos)

Convert a character at a specified position to an integer value.

Character 'X' check digit converted to 10.

Convert a character at a specified position to an integer value.

Note: this implementation only handlers numeric values For non-numeric characters, override this method to provide character-->integer conversion.

Parameters:

character - The character to convert

leftPos - The position of the character in the code, counting from left to right

rightPos - The positionof the character in the code, counting from right to left

Returns:

The integer value of the character

initialize

public final void initialize(A annotation)

Specified by:

initialize in interface javax.validation.ConstraintValidator<A extends Annotation,CharSequence>

isValid

public boolean isValid(CharSequence code,
                       javax.validation.ConstraintValidatorContext context)

Specified by:

isValid in interface javax.validation.ConstraintValidator<A extends Annotation,CharSequence>

sumDigits

protected static int sumDigits(int number)

Add together the individual digits in a number.

Parameters:

number - The number whose digits are to be added

Returns:

The sum of the digits