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

java.lang.Object
  extended by org.apache.bval.extras.constraints.checkdigit.ModulusValidator<ISBN10>
      extended by org.apache.bval.extras.constraints.checkdigit.ISBN10Validator
All Implemented Interfaces:
ConstraintValidator<ISBN10,String>

public final class ISBN10Validator
extends ModulusValidator<ISBN10>

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:


Constructor Summary
ISBN10Validator()
           
 
Method Summary
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 org.apache.bval.extras.constraints.checkdigit.ModulusValidator
initialize, isValid, sumDigits
 
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.

Specified by:
weightedValue in class ModulusValidator<ISBN10>
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.

Overrides:
toInt in class ModulusValidator<ISBN10>
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


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