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:

Since:
1.4
See Also:
  • Field Details

  • Constructor Details

    • 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.