org.apache.commons.validator

Class ISBNValidator

public class ISBNValidator extends Object

A class for validating 10 digit ISBN codes. Based on this algorithm

Since: Validator 1.2.0

Version: $Revision: 478334 $ $Date: 2006-11-22 21:31:54 +0000 (Wed, 22 Nov 2006) $

Field Summary
static String	CHECK
static String	GROUP
static String	ISBN_PATTERN ISBN consists of 4 groups of numbers separated by either dashes (-) or spaces.
static String	PUBLISHER
static String	SEP
static String	TITLE

Constructor Summary
	ISBNValidator() Default Constructor.

Method Summary
String	clean(String isbn) Removes all non-digit characters except for 'X' which is a valid ISBN character.
boolean	isFormatted(String isbn) Returns true if the ISBN contains one of the separator characters space or dash.
boolean	isValid(String isbn) If the ISBN is formatted with space or dash separators its format is validated.
boolean	isValidPattern(String isbn) Returns true if the ISBN is formatted properly.
int	sum(String isbn) Returns the sum of the weighted ISBN characters.
int	toInt(char ch) Returns the numeric value represented by the character.

Field Detail

ISBN_PATTERN

private static final String ISBN_PATTERN

ISBN consists of 4 groups of numbers separated by either dashes (-) or spaces. The first group is 1-5 characters, second 1-7, third 1-6, and fourth is 1 digit or an X.

Constructor Detail

ISBNValidator

public ISBNValidator()

Default Constructor.

Method Detail

clean

private String clean(String isbn)

Removes all non-digit characters except for 'X' which is a valid ISBN character.

isFormatted

private boolean isFormatted(String isbn)

Returns true if the ISBN contains one of the separator characters space or dash.

If the ISBN is formatted with space or dash separators its format is validated. Then the digits in the number are weighted, summed, and divided by 11 according to the ISBN algorithm. If the result is zero, the ISBN is valid. This method accepts formatted or raw ISBN codes.

Parameters: isbn Candidate ISBN number to be validated. null is considered invalid.

Returns: true if the string is a valid ISBN code.

isValidPattern

private boolean isValidPattern(String isbn)

Returns true if the ISBN is formatted properly.

sum

private int sum(String isbn)

Returns the sum of the weighted ISBN characters.

toInt

private int toInt(char ch)

Returns the numeric value represented by the character. If the character is not a digit but an 'X', 10 is returned.