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

Class ModulusTenCheckDigit

  • All Implemented Interfaces:
    java.io.Serializable, CheckDigit
    public final class ModulusTenCheckDigit
extends ModulusCheckDigit
    General Modulus 10 Check Digit calculation/validation.

    How if 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 postitionWeight 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:
    Validator 1.6
    Version:
    $Revision: 1739356 $
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      ModulusTenCheckDigit​(int[] postitionWeight)
      Construct a modulus 10 Check Digit routine with the specified weighting from left to right.
      ModulusTenCheckDigit​(int[] postitionWeight, boolean useRightPos)
      Construct a modulus 10 Check Digit routine with the specified weighting, indicating whether its from the left or right.
      ModulusTenCheckDigit​(int[] postitionWeight, boolean useRightPos, boolean sumWeightedDigits)
      Construct 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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean isValid​(java.lang.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.
      java.lang.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 java.lang.Object

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

    • Constructor Detail

      • ModulusTenCheckDigit

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

      • ModulusTenCheckDigit

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

      • ModulusTenCheckDigit

        public ModulusTenCheckDigit​(int[] postitionWeight,
                            boolean useRightPos,
                            boolean sumWeightedDigits)
        Construct 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:
        postitionWeight - 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 Detail

      • isValid

        public boolean isValid​(java.lang.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

      • 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.

      • toString

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