1 | /** |
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2 | * This software is copyright (c) 2011-2022 by |
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3 | * - Leibniz-Institut fuer Deutsche Sprache (http://www.ids-mannheim.de) |
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4 | * This is free software. You can redistribute it |
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5 | * and/or modify it under the terms described in |
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6 | * the GNU General Public License v3 of which you |
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7 | * should have received a copy. Otherwise you can download |
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8 | * it from |
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9 | * |
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10 | * http://www.gnu.org/licenses/gpl-3.0.txt |
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11 | * |
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12 | * @copyright Leibniz-Institut fuer Deutsche Sprache (http://www.ids-mannheim.de) |
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13 | * |
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14 | * @license http://www.gnu.org/licenses/gpl-3.0.txt |
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15 | * GNU General Public License v3 |
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16 | */ |
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17 | package eu.clarin.sru.server; |
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18 | |
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19 | import java.util.ArrayList; |
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20 | import java.util.Collections; |
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21 | import java.util.List; |
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22 | |
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23 | |
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24 | /** |
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25 | * A registry to keep track of registered {@link SRUQueryParser} to be used by |
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26 | * the {@link SRUServer}. |
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27 | * |
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28 | * @see SRUQueryParser |
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29 | */ |
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30 | public class SRUQueryParserRegistry { |
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31 | private final List<SRUQueryParser<?>> parsers; |
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32 | |
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33 | |
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34 | /** |
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35 | * Constructor. |
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36 | */ |
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37 | private SRUQueryParserRegistry(List<SRUQueryParser<?>> parsers) { |
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38 | if (parsers == null) { |
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39 | throw new NullPointerException("parsers == null"); |
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40 | } |
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41 | if (parsers.isEmpty()) { |
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42 | throw new IllegalArgumentException("parsers is empty!"); |
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43 | } |
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44 | this.parsers = Collections.unmodifiableList(parsers); |
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45 | } |
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46 | |
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47 | |
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48 | /** |
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49 | * Find a query parser by query type. |
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50 | * |
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51 | * @param queryType |
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52 | * the query type to search for |
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53 | * @return the matching {@link SRUQueryParser} instance or <code>null</code> |
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54 | * if no matching parser was found. |
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55 | */ |
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56 | public SRUQueryParser<?> findQueryParser(String queryType) { |
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57 | if (queryType == null) { |
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58 | throw new NullPointerException("queryType == null"); |
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59 | } |
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60 | return findParser(parsers, queryType); |
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61 | } |
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62 | |
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63 | |
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64 | /** |
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65 | * Get a list of all registered query parsers. |
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66 | * |
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67 | * @return a list of registered query parsers |
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68 | */ |
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69 | public List<SRUQueryParser<?>> getQueryParsers() { |
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70 | return parsers; |
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71 | } |
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72 | |
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73 | |
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74 | /** |
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75 | * Builder for creating {@link SRUQueryParserRegistry} instances. |
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76 | */ |
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77 | public static class Builder { |
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78 | private final List<SRUQueryParser<?>> parsers = |
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79 | new ArrayList<SRUQueryParser<?>>(); |
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80 | |
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81 | |
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82 | /** |
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83 | * Constructor. |
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84 | * |
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85 | * @param registerDefaults |
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86 | * if <code>true</code>, register SRU/CQL standard query |
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87 | * parsers (queryType <em>cql</em> and <em>searchTerms</em>), |
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88 | * otherwise do nothing |
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89 | */ |
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90 | public Builder(boolean registerDefaults) { |
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91 | if (registerDefaults) { |
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92 | registerDefaults(); |
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93 | } |
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94 | } |
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95 | |
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96 | |
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97 | /** |
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98 | * Constructor. Automaticaly registers registers SRU/CQL standard query |
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99 | * parsers (queryType <em>cql</em> and <em>searchTerms</em>). |
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100 | */ |
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101 | public Builder() { |
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102 | this(true); |
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103 | } |
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104 | |
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105 | |
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106 | public Builder registerDefaults() { |
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107 | if (findParser(parsers, SRUConstants.SRU_QUERY_TYPE_CQL) == null) { |
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108 | try { |
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109 | register(new CQLQueryParser()); |
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110 | } catch (SRUConfigException e) { |
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111 | /* IGNORE */ |
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112 | } |
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113 | } |
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114 | if (findParser(parsers, SRUConstants.SRU_QUERY_TYPE_SEARCH_TERMS) == null) { |
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115 | try { |
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116 | register(new SearchTermsQueryParser()); |
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117 | } catch (SRUConfigException e) { |
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118 | /* IGNORE */ |
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119 | } |
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120 | } |
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121 | return this; |
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122 | } |
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123 | |
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124 | |
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125 | /** |
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126 | * Register a new query parser |
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127 | * |
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128 | * @param parser |
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129 | * the query parser instance to be registered |
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130 | * @return this {@link Builder} instance (to allow chaining) |
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131 | * @throws SRUConfigException |
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132 | * if a query parser for the same query type was already |
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133 | * registered |
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134 | */ |
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135 | public Builder register(SRUQueryParser<?> parser) throws SRUConfigException { |
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136 | if (parser == null) { |
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137 | throw new NullPointerException("parser == null"); |
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138 | } |
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139 | if (parser.getQueryType() == null) { |
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140 | throw new NullPointerException("parser.getQueryType() == null"); |
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141 | } |
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142 | |
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143 | // duplicate-save add ... |
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144 | if (findParser(parsers, parser.getQueryType()) == null) { |
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145 | parsers.add(parser); |
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146 | } else { |
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147 | throw new SRUConfigException("query parser for queryType '" + |
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148 | parser.getQueryType() + "' is already registered"); |
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149 | } |
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150 | |
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151 | return this; |
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152 | } |
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153 | |
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154 | |
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155 | /** |
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156 | * Create a configured {@link SRUQueryParserRegistry} instance from this |
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157 | * builder. |
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158 | * |
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159 | * @return a {@link SRUQueryParserRegistry} instance |
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160 | */ |
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161 | public SRUQueryParserRegistry build() { |
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162 | return new SRUQueryParserRegistry(parsers); |
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163 | } |
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164 | } |
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165 | |
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166 | |
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167 | private static final SRUQueryParser<?> findParser( |
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168 | List<SRUQueryParser<?>> parsers, String queryType) { |
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169 | for (SRUQueryParser<?> parser : parsers) { |
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170 | if (queryType.equals(parser.getQueryType())) { |
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171 | return parser; |
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172 | } |
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173 | } |
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174 | return null; |
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175 | } |
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176 | |
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177 | } // class SRUQueryParserRegistry |
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