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

Class ModulusTenCheckDigit

java.lang.Object
org.apache.commons.validator.routines.checkdigit.ModulusCheckDigit
org.apache.commons.validator.routines.checkdigit.ModulusTenCheckDigit
All Implemented Interfaces:
Serializable, CheckDigit
public final class ModulusTenCheckDigit extends ModulusCheckDigit
General Modulus 10 Check Digit calculation/validation.

How it Works

This implementation calculates/validates the check digit in the following way:

  • Converting each character to an integer value using Character.getNumericValue(char) - negative integer values from that method are invalid.
  • Calculating a weighted value by multiplying the character's integer value by a weighting factor. The weighting factor is selected from the configured positionWeight array based on its position. The postitionWeight values are used either left-to-right (when useRightPos=false) or right-to-left (when useRightPos=true).
  • If sumWeightedDigits=true, the weighted value is re-calculated by summing its digits.
  • The weighted values of each character are totalled.
  • The total modulo 10 will be zero for a code with a valid Check Digit.

Limitations

This implementation has the following limitations:

  • It assumes the last character in the code is the Check Digit and validates that it is a numeric character.
  • The only limitation on valid characters are those that Character.getNumericValue(char) returns a positive value. If, for example, the code should only contain numbers, this implementation does not check that.
  • There are no checks on code length.

Note: This implementation can be combined with the CodeValidator in order to ensure the length and characters are valid.

Example Usage

This implementation was added after a number of Modulus 10 routines and these are shown re-implemented using this routine below:

ABA Number Check Digit Routine (equivalent of ABANumberCheckDigit). Weighting factors are [1, 7, 3] applied from right to left. 

 CheckDigit routine = new ModulusTenCheckDigit(new int[] { 1, 7, 3 }, true);

CUSIP Check Digit Routine (equivalent of CUSIPCheckDigit). Weighting factors are [1, 2] applied from right to left and the digits of the weighted value are summed. 

 CheckDigit routine = new ModulusTenCheckDigit(new int[] { 1, 2 }, true, true);

EAN-13 / UPC Check Digit Routine (equivalent of EAN13CheckDigit). Weighting factors are [1, 3] applied from right to left. 

 CheckDigit routine = new ModulusTenCheckDigit(new int[] { 1, 3 }, true);

Luhn Check Digit Routine (equivalent of LuhnCheckDigit). Weighting factors are [1, 2] applied from right to left and the digits of the weighted value are summed. 

 CheckDigit routine = new ModulusTenCheckDigit(new int[] { 1, 2 }, true, true);

SEDOL Check Digit Routine (equivalent of SedolCheckDigit). Weighting factors are [1, 3, 1, 7, 3, 9, 1] applied from left to right. 

 CheckDigit routine = new ModulusTenCheckDigit(new int[] { 1, 3, 1, 7, 3, 9, 1 });
Since:
1.6
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    ModulusTenCheckDigit(int[] positionWeight)
    Constructs a modulus 10 Check Digit routine with the specified weighting from left to right.
    ModulusTenCheckDigit(int[] positionWeight, boolean useRightPos)
    Constructs a modulus 10 Check Digit routine with the specified weighting, indicating whether its from the left or right.
    ModulusTenCheckDigit(int[] positionWeight, boolean useRightPos, boolean sumWeightedDigits)
    Constructs a modulus 10 Check Digit routine with the specified weighting, indicating whether its from the left or right and whether the weighted digits should be summed.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    isValid(String code)
    Validate a modulus check digit for a code.
    protected int
    toInt(char character, int leftPos, int rightPos)
    Convert a character at a specified position to an integer value.
    String
    toString()
    Return a string representation of this implementation.
    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, sumDigits, toCheckDigit

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ModulusTenCheckDigit

      public ModulusTenCheckDigit(int[] positionWeight)
      Constructs a modulus 10 Check Digit routine with the specified weighting from left to right.
      Parameters:
      positionWeight - the weighted values to apply based on the character position

    • ModulusTenCheckDigit

      public ModulusTenCheckDigit(int[] positionWeight, boolean useRightPos)
      Constructs a modulus 10 Check Digit routine with the specified weighting, indicating whether its from the left or right.
      Parameters:
      positionWeight - the weighted values to apply based on the character position
      useRightPos - true if use positionWeights from right to left

    • ModulusTenCheckDigit

      public ModulusTenCheckDigit(int[] positionWeight, boolean useRightPos, boolean sumWeightedDigits)
      Constructs a modulus 10 Check Digit routine with the specified weighting, indicating whether its from the left or right and whether the weighted digits should be summed.
      Parameters:
      positionWeight - the weighted values to apply based on the character position
      useRightPos - true if use positionWeights from right to left
      sumWeightedDigits - true if sum the digits of the weighted value

  • Method Details

    • isValid

      public boolean isValid(String code)
      Validate a modulus check digit for a code.

      Note: assumes last digit is the check digit

      Specified by:
      isValid in interface CheckDigit
      Overrides:
      isValid in class ModulusCheckDigit
      Parameters:
      code - The code to validate
      Returns:
      true if the check digit is valid, otherwise false

    • toInt

      protected int toInt(char character, int leftPos, int rightPos) throws CheckDigitException
      Convert a character at a specified position to an integer value.

      Note: this implementation only handlers values that Character.getNumericValue(char) returns a non-negative number.

      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 (for identifying the position in the string)
      rightPos - The position of the character in the code, counting from right to left (not used here)
      Returns:
      The integer value of the character
      Throws:
      CheckDigitException - if Character.getNumericValue(char) returns a negative number

    • toString

      public String toString()
      Return a string representation of this implementation.
      Overrides:
      toString in class Object
      Returns:
      a string representation

    • weightedValue

      protected int weightedValue(int charValue, int leftPos, int rightPos)
      Calculates the weighted value of a character in the code at a specified 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 position of the character in the code, counting from right to left
      Returns:
      The weighted value of the character.