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org.apache.commons.validator.ISBNValidator |
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1 | /* |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with |
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4 | * this work for additional information regarding copyright ownership. |
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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6 | * (the "License"); you may not use this file except in compliance with |
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7 | * the License. You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | */ |
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17 | package org.apache.commons.validator; |
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18 | ||
19 | import org.apache.oro.text.perl.Perl5Util; |
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20 | ||
21 | /** |
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22 | * A class for validating 10 digit ISBN codes. |
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23 | * Based on this |
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24 | * <a href="http://www.isbn.org/standards/home/isbn/international/html/usm4.htm"> |
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25 | * algorithm</a> |
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26 | * |
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27 | * @version $Revision: 478334 $ $Date: 2006-11-22 21:31:54 +0000 (Wed, 22 Nov 2006) $ |
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28 | * @since Validator 1.2.0 |
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29 | */ |
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30 | public class ISBNValidator { |
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31 | ||
32 | private static final String SEP = "(\\-|\\s)"; |
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33 | private static final String GROUP = "(\\d{1,5})"; |
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34 | private static final String PUBLISHER = "(\\d{1,7})"; |
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35 | private static final String TITLE = "(\\d{1,6})"; |
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36 | private static final String CHECK = "([0-9X])"; |
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37 | ||
38 | /** |
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39 | * ISBN consists of 4 groups of numbers separated by either dashes (-) |
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40 | * or spaces. The first group is 1-5 characters, second 1-7, third 1-6, |
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41 | * and fourth is 1 digit or an X. |
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42 | */ |
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43 | private static final String ISBN_PATTERN = |
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44 | "/^" + GROUP + SEP + PUBLISHER + SEP + TITLE + SEP + CHECK + "$/"; |
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45 | ||
46 | /** |
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47 | * Default Constructor. |
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48 | */ |
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49 | public ISBNValidator() { |
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50 | 1 | super(); |
51 | 1 | } |
52 | ||
53 | /** |
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54 | * If the ISBN is formatted with space or dash separators its format is |
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55 | * validated. Then the digits in the number are weighted, summed, and |
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56 | * divided by 11 according to the ISBN algorithm. If the result is zero, |
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57 | * the ISBN is valid. This method accepts formatted or raw ISBN codes. |
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58 | * |
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59 | * @param isbn Candidate ISBN number to be validated. <code>null</code> is |
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60 | * considered invalid. |
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61 | * @return true if the string is a valid ISBN code. |
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62 | */ |
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63 | public boolean isValid(String isbn) { |
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64 | 15 | if (isbn == null || isbn.length() < 10 || isbn.length() > 13) { |
65 | 9 | return false; |
66 | } |
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67 | ||
68 | 6 | if (isFormatted(isbn) && !isValidPattern(isbn)) { |
69 | 1 | return false; |
70 | } |
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71 | ||
72 | 5 | isbn = clean(isbn); |
73 | 5 | if (isbn.length() != 10) { |
74 | 1 | return false; |
75 | } |
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76 | ||
77 | 4 | return (sum(isbn) % 11) == 0; |
78 | } |
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79 | ||
80 | /** |
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81 | * Returns the sum of the weighted ISBN characters. |
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82 | */ |
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83 | private int sum(String isbn) { |
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84 | 4 | int total = 0; |
85 | 40 | for (int i = 0; i < 9; i++) { |
86 | 36 | int weight = 10 - i; |
87 | 36 | total += (weight * toInt(isbn.charAt(i))); |
88 | } |
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89 | 4 | total += toInt(isbn.charAt(9)); // add check digit |
90 | 4 | return total; |
91 | } |
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92 | ||
93 | /** |
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94 | * Removes all non-digit characters except for 'X' which is a valid ISBN |
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95 | * character. |
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96 | */ |
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97 | private String clean(String isbn) { |
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98 | 5 | StringBuffer buf = new StringBuffer(10); |
99 | ||
100 | 66 | for (int i = 0; i < isbn.length(); i++) { |
101 | 61 | char digit = isbn.class="keyword">charAt(i); |
102 | 61 | if (Character.isDigit(digit) || (digit == 'X')) { |
103 | 40 | buf.append(digit); |
104 | } |
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105 | } |
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106 | ||
107 | 5 | return buf.toString(); |
108 | } |
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109 | ||
110 | /** |
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111 | * Returns the numeric value represented by the character. If the |
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112 | * character is not a digit but an 'X', 10 is returned. |
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113 | */ |
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114 | private int toInt(char ch) { |
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115 | 40 | return (ch == 'X') ? 10 : Character.getNumericValue(ch); |
116 | } |
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117 | ||
118 | /** |
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119 | * Returns true if the ISBN contains one of the separator characters space |
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120 | * or dash. |
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121 | */ |
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122 | private boolean isFormatted(String isbn) { |
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123 | 6 | return ((isbn.indexOf('-') != -1) || (isbn.indexOf(' ') != -1)); |
124 | } |
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125 | ||
126 | /** |
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127 | * Returns true if the ISBN is formatted properly. |
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128 | */ |
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129 | private boolean isValidPattern(String isbn) { |
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130 | 4 | return new Perl5Util().match(ISBN_PATTERN, isbn); |
131 | } |
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132 | ||
133 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |