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

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

All Implemented Interfaces:

java.io.Serializable, CheckDigit

public final class VerhoeffCheckDigit
extends java.lang.Object
implements CheckDigit, java.io.Serializable

Verhoeff (Dihedral) Check Digit calculation/validation.

Check digit calculation for numeric codes using a Dihedral Group of order 10.

See Wikipedia - Verhoeff algorithm for more details.

Since:

Validator 1.4

Version:

$Revision: 493905 $ $Date: 2007-01-08 03:11:38 +0100 (Mo, 08. Jan 2007) $

See Also:

Serialized Form

Field Summary

private static int[][]	D_TABLE D - multiplication table
static CheckDigit	INSTANCE Singleton Verhoeff Check Digit instance
private static int[]	INV_TABLE inv: inverse table
private static int[][]	P_TABLE P - permutation table

Constructor Summary

VerhoeffCheckDigit()

Method Summary

java.lang.String	calculate(java.lang.String code) Calculate a Verhoeff Check Digit for a code.
private int	calculateChecksum(java.lang.String code, boolean includesCheckDigit) Calculate the checksum.
boolean	isValid(java.lang.String code) Validate the Verhoeff Check Digit for a code.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final CheckDigit INSTANCE

Singleton Verhoeff Check Digit instance

D_TABLE

private static final int[][] D_TABLE

D - multiplication table

P_TABLE

private static final int[][] P_TABLE

P - permutation table

INV_TABLE

private static final int[] INV_TABLE

inv: inverse table

Constructor Detail

VerhoeffCheckDigit

public VerhoeffCheckDigit()

Method Detail

isValid

public boolean isValid(java.lang.String code)

Validate the Verhoeff 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 Verhoeff 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

calculateChecksum

private int calculateChecksum(java.lang.String code,
                              boolean includesCheckDigit)
                       throws CheckDigitException

Calculate the checksum.

Parameters:

code - The code to calculate the checksum for.

includesCheckDigit - Whether the code includes the Check Digit or not.

Returns:

The checksum value

Throws:

CheckDigitException - if the code contains an invalid character (i.e. not numeric)