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 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 and 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

Modifier and Type	Method and 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 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(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 String toString()

Return a string representation of this implementation.

Overrides:

toString in class Object

Returns:

a string representation