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 */
017 package org.apache.commons.validator.routines.checkdigit;
018
019 import 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} or the
027 * {@link ISBNCheckDigit#ISBN13} 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 * @version $Revision: 493905 $ $Date: 2007-01-08 03:11:38 +0100 (Mo, 08. Jan 2007) $
035 * @since Validator 1.4
036 */
037 public final class ISBNCheckDigit implements CheckDigit, Serializable {
038
039 /** Singleton ISBN-10 Check Digit instance */
040 public static final CheckDigit ISBN10 = ISBN10CheckDigit.INSTANCE;
041
042 /** Singleton ISBN-13 Check Digit instance */
043 public static final CheckDigit ISBN13 = EAN13CheckDigit.INSTANCE;
044
045 /** Singleton combined ISBN-10 / ISBN-13 Check Digit instance */
046 public static final CheckDigit ISBN = new ISBNCheckDigit();
047
048 /**
049 * Calculate an ISBN-10 or ISBN-13 check digit, depending
050 * on the length of the code.
051 * <p>
052 * If the length of the code is 9, it is treated as an ISBN-10
053 * code or if the length of the code is 12, it is treated as an ISBN-13
054 * code.
055 *
056 * @param code The ISBN code to validate (should have a length of
057 * 9 or 12)
058 * @return The ISBN-10 check digit if the length is 9 or an ISBN-13
059 * check digit if the length is 12.
060 * @throws CheckDigitException if the code is missing, or an invalid
061 * length (i.e. not 9 or 12) or if there is an error calculating the
062 * check digit.
063 */
064 public String calculate(String code) throws CheckDigitException {
065 if (code == null || code.length() == 0) {
066 throw new CheckDigitException("ISBN Code is missing");
067 } else if (code.length() == 9) {
068 return ISBN10.calculate(code);
069 } else if (code.length() == 12) {
070 return ISBN13.calculate(code);
071 } else {
072 throw new CheckDigitException("Invalid ISBN Length = " + code.length());
073 }
074 }
075
076 /**
077 * <p>Validate an ISBN-10 or ISBN-13 check digit, depending
078 * on the length of the code.</p>
079 * <p>
080 * If the length of the code is 10, it is treated as an ISBN-10
081 * code or ff the length of the code is 13, it is treated as an ISBN-13
082 * code.
083 *
084 * @param code The ISBN code to validate (should have a length of
085 * 10 or 13)
086 * @return <code>true</code> if the code has a length of 10 and is
087 * a valid ISBN-10 check digit or the code has a length of 13 and is
088 * a valid ISBN-13 check digit - otherwise <code>false</code>.
089 */
090 public boolean isValid(String code) {
091 if (code == null) {
092 return false;
093 } else if (code.length() == 10) {
094 return ISBN10.isValid(code);
095 } else if (code.length() == 13) {
096 return ISBN13.isValid(code);
097 } else {
098 return false;
099 }
100 }
101
102 }