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org.apache.commons.validator.ISBNValidator |
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1 | /* |
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2 | * $Id: ISBNValidator.java 280974 2005-09-15 00:06:59Z niallp $ |
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3 | * $Rev: 280974 $ |
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4 | * $Date: 2005-09-15 01:06:59 +0100 (Thu, 15 Sep 2005) $ |
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5 | * |
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6 | * ==================================================================== |
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7 | * Copyright 2004-2005 The Apache Software Foundation |
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8 | * |
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9 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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10 | * you may not use this file except in compliance with the License. |
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11 | * You may obtain a copy of the License at |
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12 | * |
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13 | * http://www.apache.org/licenses/LICENSE-2.0 |
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14 | * |
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15 | * Unless required by applicable law or agreed to in writing, software |
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16 | * distributed under the License is distributed on an "AS IS" BASIS, |
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17 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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18 | * See the License for the specific language governing permissions and |
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19 | * limitations under the License. |
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20 | */ |
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21 | ||
22 | package org.apache.commons.validator; |
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23 | ||
24 | import org.apache.oro.text.perl.Perl5Util; |
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25 | ||
26 | /** |
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27 | * A class for validating 10 digit ISBN codes. |
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28 | * Based on this |
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29 | * <a href="http://www.isbn.org/standards/home/isbn/international/html/usm4.htm"> |
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30 | * algorithm</a> |
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31 | * |
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32 | * @since Validator 1.2.0 |
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33 | */ |
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34 | public class ISBNValidator { |
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35 | ||
36 | private static final String SEP = "(\\-|\\s)"; |
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37 | private static final String GROUP = "(\\d{1,5})"; |
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38 | private static final String PUBLISHER = "(\\d{1,7})"; |
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39 | private static final String TITLE = "(\\d{1,6})"; |
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40 | private static final String CHECK = "([0-9X])"; |
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41 | ||
42 | /** |
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43 | * ISBN consists of 4 groups of numbers separated by either dashes (-) |
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44 | * or spaces. The first group is 1-5 characters, second 1-7, third 1-6, |
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45 | * and fourth is 1 digit or an X. |
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46 | */ |
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47 | private static final String ISBN_PATTERN = |
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48 | "/^" + GROUP + SEP + PUBLISHER + SEP + TITLE + SEP + CHECK + "$/"; |
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49 | ||
50 | /** |
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51 | * Default Constructor. |
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52 | */ |
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53 | public ISBNValidator() { |
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54 | 1 | super(); |
55 | 1 | } |
56 | ||
57 | /** |
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58 | * If the ISBN is formatted with space or dash separators its format is |
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59 | * validated. Then the digits in the number are weighted, summed, and |
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60 | * divided by 11 according to the ISBN algorithm. If the result is zero, |
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61 | * the ISBN is valid. This method accepts formatted or raw ISBN codes. |
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62 | * |
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63 | * @param isbn Candidate ISBN number to be validated. <code>null</code> is |
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64 | * considered invalid. |
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65 | * @return true if the string is a valid ISBN code. |
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66 | */ |
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67 | public boolean isValid(String isbn) { |
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68 | 15 | if (isbn == null || isbn.length() < 10 || isbn.length() > 13) { |
69 | 9 | return false; |
70 | } |
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71 | ||
72 | 6 | if (isFormatted(isbn) && !isValidPattern(isbn)) { |
73 | 1 | return false; |
74 | } |
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75 | ||
76 | 5 | isbn = clean(isbn); |
77 | 5 | if (isbn.length() != 10) { |
78 | 1 | return false; |
79 | } |
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80 | ||
81 | 4 | return (sum(isbn) % 11) == 0; |
82 | } |
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83 | ||
84 | /** |
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85 | * Returns the sum of the weighted ISBN characters. |
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86 | */ |
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87 | private int sum(String isbn) { |
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88 | 4 | int total = 0; |
89 | 40 | for (int i = 0; i < 9; i++) { |
90 | 36 | int weight = 10 - i; |
91 | 36 | total += (weight * toInt(isbn.charAt(i))); |
92 | } |
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93 | 4 | total += toInt(isbn.charAt(9)); // add check digit |
94 | 4 | return total; |
95 | } |
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96 | ||
97 | /** |
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98 | * Removes all non-digit characters except for 'X' which is a valid ISBN |
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99 | * character. |
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100 | */ |
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101 | private String clean(String isbn) { |
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102 | 5 | StringBuffer buf = new StringBuffer(10); |
103 | ||
104 | 66 | for (int i = 0; i < isbn.length(); i++) { |
105 | 61 | char digit = isbn.class="keyword">charAt(i); |
106 | 61 | if (Character.isDigit(digit) || (digit == 'X')) { |
107 | 40 | buf.append(digit); |
108 | } |
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109 | } |
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110 | ||
111 | 5 | return buf.toString(); |
112 | } |
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113 | ||
114 | /** |
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115 | * Returns the numeric value represented by the character. If the |
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116 | * character is not a digit but an 'X', 10 is returned. |
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117 | */ |
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118 | private int toInt(char ch) { |
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119 | 40 | return (ch == 'X') ? 10 : Character.getNumericValue(ch); |
120 | } |
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121 | ||
122 | /** |
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123 | * Returns true if the ISBN contains one of the separator characters space |
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124 | * or dash. |
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125 | */ |
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126 | private boolean isFormatted(String isbn) { |
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127 | 6 | return ((isbn.indexOf('-') != -1) || (isbn.indexOf(' ') != -1)); |
128 | } |
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129 | ||
130 | /** |
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131 | * Returns true if the ISBN is formatted properly. |
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132 | */ |
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133 | private boolean isValidPattern(String isbn) { |
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134 | 4 | return new Perl5Util().match(ISBN_PATTERN, isbn); |
135 | } |
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136 | ||
137 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |