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

Class IsoIec7064PurePolynomialSystem

java.lang.Object
org.apache.commons.validator.routines.checkdigit.ModulusCheckDigit
org.apache.commons.validator.routines.checkdigit.IsoIec7064PureSystem
org.apache.commons.validator.routines.checkdigit.IsoIec7064PurePolynomialSystem
All Implemented Interfaces:
Serializable, CheckDigit
Direct Known Subclasses:
IsoIecPolynomial11System, IsoIecPolynomial1271System, IsoIecPolynomial37System, IsoIecPolynomial661System, IsoIecPolynomial97System
public abstract class IsoIec7064PurePolynomialSystem extends IsoIec7064PureSystem
TODO comment
See Also:

  • Method Details

    • calculate

      public String calculate(String code) throws CheckDigitException
      Calculate a modulus Check Digit for a code which does not yet have one.

      The polynomial method for the pure ISO/IEC 7064 Systems is computed by multiplying the value for each Character in the string by its weight.

      Specified by:
      calculate in interface CheckDigit
      Overrides:
      calculate in class IsoIec7064PureSystem
      Parameters:
      code - The code for which to calculate the Check Digit; the check digit should not be included
      Returns:
      The calculated Check Digit
      Throws:
      CheckDigitException - if an error occurs calculating the check digit

    • calculateModulus

      protected int calculateModulus(String code, boolean includesCheckDigit) throws CheckDigitException
      Calculate the modulus for a code.

      The polynomial method for the pure ISO/IEC 7064 Systems is computed by multiplying the value for each Character in the string by its weight. The weights can be precalculated.

      Overrides:
      calculateModulus in class IsoIec7064PureSystem
      Parameters:
      code - The code to calculate the modulus for.
      includesCheckDigit - Whether the code includes the Check Digit or not.
      Returns:
      The modulus value
      Throws:
      CheckDigitException - if an error occurs calculating the modulus for the specified code

    • getWeightings

      protected int[] getWeightings()
      Gets precomputed weights. Override this in subclasses.
      Returns:
      precalculated weights defined for the first positions.

    • weightedValue

      protected int weightedValue(int charValue, int leftPos, int rightPos) throws CheckDigitException
      Description copied from class: IsoIec7064PureSystem
      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.

      Overrides because there is no need for a weight in ISO/IEC 7064 pure recursive/iterative computation. However for polynomial calculation this method is used.

      Weights are defined in subclasses for the first fifteen positions only. The series can be extended indefinitely, using the formula 

       wi = r^(i - 1) (mod M)
      where wi is the weight for Position i.

      NOTE: do not use Math.pow for high results, f.i. 10^23 (mod 97) = 56. Calculate it iteratively instead.

      Overrides:
      weightedValue in class IsoIec7064PureSystem
      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:
      CheckDigitException - if an error occurs calculating the weighted value