Class EAN13CheckDigit

java.lang.Object

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

org.apache.commons.validator.routines.checkdigit.EAN13CheckDigit

All Implemented Interfaces:

Serializable, CheckDigit

public final class EAN13CheckDigit
extends ModulusCheckDigit

Modulus 10 EAN-13 / UPC / ISBN-13 Check Digit calculation/validation.

Check digit calculation is based on modulus 10 with digits in an odd position (from right to left) being weighted 1 and even position digits being weighted 3.

For further information see:

• EAN-13 - see Wikipedia - European Article Number.
• UPC - see Wikipedia - Universal Product Code.
• ISBN-13 - see Wikipedia - International Standard Book Number (ISBN).

Since:

1.4

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final CheckDigit	EAN13_CHECK_DIGIT	Singleton EAN-13 Check Digit instance.

Constructor Summary

Constructors

Constructor	Description
EAN13CheckDigit()	Constructs a modulus 10 Check Digit routine for EAN/UPC.

Method Summary

Modifier and Type	Method	Description
boolean	isValid(String code)	Validates a modulus check digit for a code.
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 ModulusCheckDigit

calculate, calculateModulus, getModulus, sumDigits, toCheckDigit, toInt

Modifier and Type	Method	Description
String	calculate(String code)	Calculates a modulus Check Digit for a code which does not yet have one.
protected int	calculateModulus(String code, boolean includesCheckDigit)	Calculates the modulus for a code.
int	getModulus()	Gets the modulus value this check digit routine is based on.
static int	sumDigits(int number)	Adds together the individual digits in a number.
protected String	toCheckDigit(int charValue)	Converts an integer value to a check digit.
protected int	toInt(char character, int leftPos, int rightPos)	Converts a character at a specified position to an integer value.

Methods inherited from class Object

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

Field Details

EAN13_CHECK_DIGIT

public static final CheckDigit EAN13_CHECK_DIGIT

Singleton EAN-13 Check Digit instance.

Constructor Details

EAN13CheckDigit

public EAN13CheckDigit()

Constructs a modulus 10 Check Digit routine for EAN/UPC.

Method Details

isValid

public boolean isValid(String code)

Validates a modulus check digit for a code.

The weight is taken from rightPos, which does not change when a character is prepended, so ModulusCheckDigit would accept an over-length code whose leading digit lands on a no-op weight (for example a valid code with a 0 prepended). The thirteen-character length is checked here before the check digit test.

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.

weightedValue

protected int weightedValue(int charValue,
 int leftPos,
 int rightPos)

Calculates the weighted value of a character in the code at a specified position.

For EAN-13 (from right to left) odd digits are weighted with a factor of one and even digits with a factor of three.

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.