Package org.apache.commons.validator.routines.checkdigit

Class ISBN10CheckDigit

java.lang.Object

org.apache.commons.validator.routines.checkdigit.ModulusCheckDigit

org.apache.commons.validator.routines.checkdigit.ISBN10CheckDigit

All Implemented Interfaces:

Serializable, CheckDigit

public final class ISBN10CheckDigit
extends ModulusCheckDigit

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.

Since:

1.4

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final CheckDigit	ISBN10_CHECK_DIGIT	Singleton ISBN-10 Check Digit instance

Constructor Summary

Constructors

Constructor	Description
ISBN10CheckDigit()	Constructs a modulus 11 Check Digit routine for ISBN-10.

Method Summary

Modifier and Type	Method	Description
protected String	toCheckDigit(int charValue)	Convert an integer value to a character at a specified position.
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 character in the code at a specified position.

Methods inherited from class org.apache.commons.validator.routines.checkdigit.ModulusCheckDigit

calculate, calculateModulus, getModulus, isValid, sumDigits

Methods inherited from class java.lang.Object

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

Field Details

ISBN10_CHECK_DIGIT

public static final CheckDigit ISBN10_CHECK_DIGIT

Singleton ISBN-10 Check Digit instance

Constructor Details

ISBN10CheckDigit

public ISBN10CheckDigit()

Constructs a modulus 11 Check Digit routine for ISBN-10.

Method Details

toCheckDigit

protected String toCheckDigit(int charValue)
                       throws CheckDigitException

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

Value '10' for position 1 (check digit) converted to 'X'.

Overrides:

toCheckDigit in class ModulusCheckDigit

Parameters:

charValue - The integer value of the character.

Returns:

The converted character.

Throws:

CheckDigitException - if an error occurs.

toInt

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

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

Character 'X' check digit converted to 10.

Overrides:

toInt in class ModulusCheckDigit

Parameters:

character - The character to convert.

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 integer value of the character.

Throws:

CheckDigitException - if an error occurs.

weightedValue

protected int weightedValue(int charValue,
 int leftPos,
 int rightPos)

Calculates the weighted value of a character in the code at a specified position.

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

Specified by:

weightedValue in class ModulusCheckDigit

Parameters:

charValue - The numeric value of the character.

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 weighted value of the character.