org.apache.commons.validator.routines.checkdigit
Class ModulusCheckDigit

java.lang.Object
  org.apache.commons.validator.routines.checkdigit.ModulusCheckDigit

All Implemented Interfaces:

CheckDigit

Direct Known Subclasses:

EAN13CheckDigit, ISBN10CheckDigit, LuhnCheckDigit

public abstract class ModulusCheckDigit
extends java.lang.Object
implements CheckDigit

Abstract Modulus Check digit calculation/validation.

Provides a base class for building modulus Check Digit routines.

This implementation only handles numeric codes, such as EAN-13. For alphanumeric codes such as EAN-128 you will need to implement/override the toInt() and toChar() methods.

Since:

Validator 1.4

Version:

$Revision: 594917 $ $Date: 2007-11-14 16:36:40 +0100 (Mi, 14. Nov 2007) $

Field Summary

private int

modulus

Constructor Summary

ModulusCheckDigit(int modulus)
Construct a CheckDigit routine for a specified modulus.

Method Summary

java.lang.String	calculate(java.lang.String code) Calculate a modulus Check Digit for a code.
protected int	calculateModulus(java.lang.String code, boolean includesCheckDigit) Calculate the modulus for a code.
int	getModulus() Return the modulus value this check digit routine is based on.
boolean	isValid(java.lang.String code) Validate a modulus check digit for a code.
static int	sumDigits(int number) Add together the individual digits in a number.
protected java.lang.String	toCheckDigit(int charValue) Convert an integer value to a check digit.
protected int	toInt(char character, int leftPos, int rightPos) Convert a character at a specified position to an integer value.
protected abstract 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, toString, wait, wait, wait

Field Detail

modulus

private final int modulus

Constructor Detail

ModulusCheckDigit

public ModulusCheckDigit(int modulus)

Construct a CheckDigit routine for a specified modulus.

Parameters:

modulus - The modulus value to use for the check digit calculation

Method Detail

getModulus

public int getModulus()

Return the modulus value this check digit routine is based on.

Returns:

The modulus value this check digit routine is based on

isValid

public boolean isValid(java.lang.String code)

Validate a modulus check digit for a code.

Specified by:

isValid in interface CheckDigit

Parameters:

code - The code to validate

Returns:

true if the check digit is valid, otherwise false

calculate

public java.lang.String calculate(java.lang.String code)
                           throws CheckDigitException

Calculate a modulus Check Digit for a code.

Specified by:

calculate in interface CheckDigit

Parameters:

code - The code to calculate the Check Digit for

Returns:

The calculated Check Digit

Throws:

CheckDigitException - if an error occurs calculating the check digit for the specified code

calculateModulus

protected int calculateModulus(java.lang.String code,
                               boolean includesCheckDigit)
                        throws CheckDigitException

Calculate the modulus for a code.

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

weightedValue

protected abstract int weightedValue(int charValue,
                                     int leftPos,
                                     int rightPos)
                              throws CheckDigitException

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.

Parameters:

charValue - The numeric value of the character

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 weighted value of the character

Throws:

CheckDigitException - if an error occurs calculating the weighted value

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 numeric values For non-numeric characters, override this method to provide character-->integer conversion.

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

Throws:

CheckDigitException - if character is non-numeric

toCheckDigit

protected java.lang.String toCheckDigit(int charValue)
                                 throws CheckDigitException

Convert an integer value to a check digit.

Note: this implementation only handles numeric values For non-numeric characters, override this method to provide integer-->character conversion.

Parameters:

charValue - The integer value of the character

Returns:

The converted character

Throws:

CheckDigitException - if integer character value doesn't represent a numeric character

sumDigits

public static int sumDigits(int number)

Add together the individual digits in a number.

Parameters:

number - The number whose digits are to be added

Returns:

The sum of the digits