Class ISBNCheckDigit

java.lang.Object

org.apache.commons.validator.routines.checkdigit.ISBNCheckDigit

All Implemented Interfaces:

Serializable, CheckDigit

public final class ISBNCheckDigit
extends Object
implements Serializable

Combined ISBN-10 / ISBN-13 Check Digit calculation/validation.

This implementation validates/calculates ISBN check digits based on the length of the code passed to it - delegating either to the ISBN10_CHECK_DIGIT or the ISBN13_CHECK_DIGIT routines to perform the actual validation/calculation.

N.B. From 1st January 2007 the book industry will start to use a new 13 digit ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC standard.

Since:

1.4

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final CheckDigit	ISBN_CHECK_DIGIT	Singleton combined ISBN-10 / ISBN-13 Check Digit instance.
static final CheckDigit	ISBN10_CHECK_DIGIT	Singleton ISBN-10 Check Digit instance.
static final CheckDigit	ISBN13_CHECK_DIGIT	Singleton ISBN-13 Check Digit instance.

Constructor Summary

Constructors

Constructor	Description
ISBNCheckDigit()	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
String	calculate(String code)	Calculate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.
boolean	isValid(String code)	Validate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.

Methods inherited from class Object

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

Field Details

ISBN10_CHECK_DIGIT

public static final CheckDigit ISBN10_CHECK_DIGIT

Singleton ISBN-10 Check Digit instance.

ISBN13_CHECK_DIGIT

public static final CheckDigit ISBN13_CHECK_DIGIT

Singleton ISBN-13 Check Digit instance.

ISBN_CHECK_DIGIT

public static final CheckDigit ISBN_CHECK_DIGIT

Singleton combined ISBN-10 / ISBN-13 Check Digit instance.

Constructor Details

ISBNCheckDigit

public ISBNCheckDigit()

Constructs a new instance.

Method Details

calculate

public String calculate(String code)
                 throws CheckDigitException

Calculate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.

If the length of the code is 9, it is treated as an ISBN-10 code or if the length of the code is 12, it is treated as an ISBN-13 code.

Specified by:

calculate in interface CheckDigit

Parameters:

code - The ISBN code to validate (should have a length of 9 or 12).

Returns:

The ISBN-10 check digit if the length is 9 or an ISBN-13 check digit if the length is 12.

Throws:

CheckDigitException - if the code is missing, or an invalid length (that is, not 9 or 12) or if there is an error calculating the check digit.

isValid

public boolean isValid(String code)

Validate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.

If the length of the code is 10, it is treated as an ISBN-10 code or ff the length of the code is 13, it is treated as an ISBN-13 code.

Specified by:

isValid in interface CheckDigit

Parameters:

code - The ISBN code to validate (should have a length of 10 or 13).

Returns:

true if the code has a length of 10 and is a valid ISBN-10 check digit or the code has a length of 13 and is a valid ISBN-13 check digit - otherwise false.