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 * https://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 021import org.apache.commons.validator.GenericValidator; 022 023/** 024 * Combined <strong>ISBN-10</strong> / <strong>ISBN-13</strong> Check Digit calculation/validation. 025 * <p> 026 * This implementation validates/calculates ISBN check digits 027 * based on the length of the code passed to it - delegating 028 * either to the {@link ISBNCheckDigit#ISBN10_CHECK_DIGIT} or the 029 * {@link ISBNCheckDigit#ISBN13_CHECK_DIGIT} routines to perform the actual 030 * validation/calculation. 031 * <p> 032 * <strong>N.B.</strong> From 1st January 2007 the book industry will start to use a new 13 digit 033 * ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC 034 * standard. 035 * 036 * @since 1.4 037 */ 038public final class ISBNCheckDigit extends AbstractCheckDigit implements Serializable { 039 040 private static final long serialVersionUID = 1391849166205184558L; 041 042 /** Singleton ISBN-10 Check Digit instance */ 043 public static final CheckDigit ISBN10_CHECK_DIGIT = ISBN10CheckDigit.ISBN10_CHECK_DIGIT; 044 045 /** Singleton ISBN-13 Check Digit instance */ 046 public static final CheckDigit ISBN13_CHECK_DIGIT = EAN13CheckDigit.EAN13_CHECK_DIGIT; 047 048 /** Singleton combined ISBN-10 / ISBN-13 Check Digit instance */ 049 public static final CheckDigit ISBN_CHECK_DIGIT = new ISBNCheckDigit(); 050 051 /** 052 * Constructs a new instance. 053 */ 054 public ISBNCheckDigit() { 055 // empty 056 } 057 058 /** 059 * Calculate an ISBN-10 or ISBN-13 check digit, depending 060 * on the length of the code. 061 * <p> 062 * If the length of the code is 9, it is treated as an ISBN-10 063 * code or if the length of the code is 12, it is treated as an ISBN-13 064 * code. 065 * 066 * @param code The ISBN code to validate (should have a length of 067 * 9 or 12) 068 * @return The ISBN-10 check digit if the length is 9 or an ISBN-13 069 * check digit if the length is 12. 070 * @throws CheckDigitException if the code is missing, or an invalid 071 * length (that is, not 9 or 12) or if there is an error calculating the 072 * check digit. 073 */ 074 @Override 075 public String calculate(final String code) throws CheckDigitException { 076 if (GenericValidator.isBlankOrNull(code)) { 077 throw new CheckDigitException("ISBN Code is missing"); 078 } 079 if (code.length() == 9) { // CHECKSTYLE IGNORE MagicNumber 080 return ISBN10_CHECK_DIGIT.calculate(code); 081 } 082 if (code.length() == 12) { // CHECKSTYLE IGNORE MagicNumber 083 return ISBN13_CHECK_DIGIT.calculate(code); 084 } 085 throw new CheckDigitException("Invalid ISBN Length = " + code.length()); 086 } 087 088 /** 089 * <p>Validate an ISBN-10 or ISBN-13 check digit, depending 090 * on the length of the code.</p> 091 * <p> 092 * If the length of the code is 10, it is treated as an ISBN-10 093 * code or ff the length of the code is 13, it is treated as an ISBN-13 094 * code. 095 * 096 * @param code The ISBN code to validate (should have a length of 097 * 10 or 13) 098 * @return {@code true} if the code has a length of 10 and is 099 * a valid ISBN-10 check digit or the code has a length of 13 and is 100 * a valid ISBN-13 check digit - otherwise {@code false}. 101 */ 102 @Override 103 public boolean isValid(final String code) { 104 if (code == null) { 105 return false; 106 } 107 if (code.length() == 10) { // CHECKSTYLE IGNORE MagicNumber 108 return ISBN10_CHECK_DIGIT.isValid(code); 109 } 110 if (code.length() == 13) { // CHECKSTYLE IGNORE MagicNumber 111 return ISBN13_CHECK_DIGIT.isValid(code); 112 } 113 return false; 114 } 115 116}