1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.validator.routines.checkdigit;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.validator.GenericValidator;
22
23 /**
24 * Combined <b>ISBN-10</b> / <b>ISBN-13</b> Check Digit calculation/validation.
25 * <p>
26 * This implementation validates/calculates ISBN check digits
27 * based on the length of the code passed to it - delegating
28 * either to the {@link ISBNCheckDigit#ISBN10_CHECK_DIGIT} or the
29 * {@link ISBNCheckDigit#ISBN13_CHECK_DIGIT} routines to perform the actual
30 * validation/calculation.
31 * <p>
32 * <b>N.B.</b> From 1st January 2007 the book industry will start to use a new 13 digit
33 * ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC
34 * standard.
35 *
36 * @since 1.4
37 */
38 public final class ISBNCheckDigit extends AbstractCheckDigit implements Serializable {
39
40 private static final long serialVersionUID = 1391849166205184558L;
41
42 /** Singleton ISBN-10 Check Digit instance */
43 public static final CheckDigit ISBN10_CHECK_DIGIT = ISBN10CheckDigit.ISBN10_CHECK_DIGIT;
44
45 /** Singleton ISBN-13 Check Digit instance */
46 public static final CheckDigit ISBN13_CHECK_DIGIT = EAN13CheckDigit.EAN13_CHECK_DIGIT;
47
48 /** Singleton combined ISBN-10 / ISBN-13 Check Digit instance */
49 public static final CheckDigit ISBN_CHECK_DIGIT = new ISBNCheckDigit();
50
51 /**
52 * Calculate an ISBN-10 or ISBN-13 check digit, depending
53 * on the length of the code.
54 * <p>
55 * If the length of the code is 9, it is treated as an ISBN-10
56 * code or if the length of the code is 12, it is treated as an ISBN-13
57 * code.
58 *
59 * @param code The ISBN code to validate (should have a length of
60 * 9 or 12)
61 * @return The ISBN-10 check digit if the length is 9 or an ISBN-13
62 * check digit if the length is 12.
63 * @throws CheckDigitException if the code is missing, or an invalid
64 * length (i.e. not 9 or 12) or if there is an error calculating the
65 * check digit.
66 */
67 @Override
68 public String calculate(final String code) throws CheckDigitException {
69 if (GenericValidator.isBlankOrNull(code)) {
70 throw new CheckDigitException("ISBN Code is missing");
71 }
72 if (code.length() == 9) { // CHECKSTYLE IGNORE MagicNumber
73 return ISBN10_CHECK_DIGIT.calculate(code);
74 }
75 if (code.length() == 12) { // CHECKSTYLE IGNORE MagicNumber
76 return ISBN13_CHECK_DIGIT.calculate(code);
77 }
78 throw new CheckDigitException("Invalid ISBN Length = " + code.length());
79 }
80
81 /**
82 * <p>Validate an ISBN-10 or ISBN-13 check digit, depending
83 * on the length of the code.</p>
84 * <p>
85 * If the length of the code is 10, it is treated as an ISBN-10
86 * code or ff the length of the code is 13, it is treated as an ISBN-13
87 * code.
88 *
89 * @param code The ISBN code to validate (should have a length of
90 * 10 or 13)
91 * @return {@code true} if the code has a length of 10 and is
92 * a valid ISBN-10 check digit or the code has a length of 13 and is
93 * a valid ISBN-13 check digit - otherwise {@code false}.
94 */
95 @Override
96 public boolean isValid(final String code) {
97 if (code == null) {
98 return false;
99 }
100 if (code.length() == 10) { // CHECKSTYLE IGNORE MagicNumber
101 return ISBN10_CHECK_DIGIT.isValid(code);
102 }
103 if (code.length() == 13) { // CHECKSTYLE IGNORE MagicNumber
104 return ISBN13_CHECK_DIGIT.isValid(code);
105 }
106 return false;
107 }
108
109 }