001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.validator.routines.checkdigit; 018 019import java.io.Serializable; 020 021/** 022 * Combined <b>ISBN-10</b> / <b>ISBN-13</b> Check Digit calculation/validation. 023 * <p> 024 * This implementation validates/calculates ISBN check digits 025 * based on the length of the code passed to it - delegating 026 * either to the {@link ISBNCheckDigit#ISBN10_CHECK_DIGIT} or the 027 * {@link ISBNCheckDigit#ISBN13_CHECK_DIGIT} routines to perform the actual 028 * validation/calculation. 029 * <p> 030 * <b>N.B.</b> From 1st January 2007 the book industry will start to use a new 13 digit 031 * ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC 032 * standard. 033 * 034 * @since 1.4 035 */ 036public final class ISBNCheckDigit implements CheckDigit, Serializable { 037 038 private static final long serialVersionUID = 1391849166205184558L; 039 040 /** Singleton ISBN-10 Check Digit instance */ 041 public static final CheckDigit ISBN10_CHECK_DIGIT = ISBN10CheckDigit.ISBN10_CHECK_DIGIT; 042 043 /** Singleton ISBN-13 Check Digit instance */ 044 public static final CheckDigit ISBN13_CHECK_DIGIT = EAN13CheckDigit.EAN13_CHECK_DIGIT; 045 046 /** Singleton combined ISBN-10 / ISBN-13 Check Digit instance */ 047 public static final CheckDigit ISBN_CHECK_DIGIT = new ISBNCheckDigit(); 048 049 /** 050 * Calculate an ISBN-10 or ISBN-13 check digit, depending 051 * on the length of the code. 052 * <p> 053 * If the length of the code is 9, it is treated as an ISBN-10 054 * code or if the length of the code is 12, it is treated as an ISBN-13 055 * code. 056 * 057 * @param code The ISBN code to validate (should have a length of 058 * 9 or 12) 059 * @return The ISBN-10 check digit if the length is 9 or an ISBN-13 060 * check digit if the length is 12. 061 * @throws CheckDigitException if the code is missing, or an invalid 062 * length (i.e. not 9 or 12) or if there is an error calculating the 063 * check digit. 064 */ 065 @Override 066 public String calculate(final String code) throws CheckDigitException { 067 if (code == null || code.isEmpty()) { 068 throw new CheckDigitException("ISBN Code is missing"); 069 } 070 if (code.length() == 9) { // CHECKSTYLE IGNORE MagicNumber 071 return ISBN10_CHECK_DIGIT.calculate(code); 072 } 073 if (code.length() == 12) { // CHECKSTYLE IGNORE MagicNumber 074 return ISBN13_CHECK_DIGIT.calculate(code); 075 } 076 throw new CheckDigitException("Invalid ISBN Length = " + code.length()); 077 } 078 079 /** 080 * <p>Validate an ISBN-10 or ISBN-13 check digit, depending 081 * on the length of the code.</p> 082 * <p> 083 * If the length of the code is 10, it is treated as an ISBN-10 084 * code or ff the length of the code is 13, it is treated as an ISBN-13 085 * code. 086 * 087 * @param code The ISBN code to validate (should have a length of 088 * 10 or 13) 089 * @return {@code true} if the code has a length of 10 and is 090 * a valid ISBN-10 check digit or the code has a length of 13 and is 091 * a valid ISBN-13 check digit - otherwise {@code false}. 092 */ 093 @Override 094 public boolean isValid(final String code) { 095 if (code == null) { 096 return false; 097 } 098 if (code.length() == 10) { // CHECKSTYLE IGNORE MagicNumber 099 return ISBN10_CHECK_DIGIT.isValid(code); 100 } 101 if (code.length() == 13) { // CHECKSTYLE IGNORE MagicNumber 102 return ISBN13_CHECK_DIGIT.isValid(code); 103 } 104 return false; 105 } 106 107}