1 | /** |
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2 | * This software is copyright (c) 2012-2016 by |
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3 | * - 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 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.client.fcs; |
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18 | |
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19 | import javax.xml.parsers.DocumentBuilder; |
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20 | import javax.xml.parsers.DocumentBuilderFactory; |
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21 | import javax.xml.parsers.ParserConfigurationException; |
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22 | import javax.xml.stream.XMLStreamException; |
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23 | import javax.xml.stream.XMLStreamReader; |
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24 | import javax.xml.transform.Transformer; |
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25 | import javax.xml.transform.TransformerConfigurationException; |
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26 | import javax.xml.transform.TransformerException; |
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27 | import javax.xml.transform.TransformerFactory; |
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28 | import javax.xml.transform.dom.DOMResult; |
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29 | import javax.xml.transform.stax.StAXSource; |
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30 | |
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31 | import org.w3c.dom.Document; |
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32 | import org.w3c.dom.NodeList; |
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33 | |
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34 | import eu.clarin.sru.client.SRUClientException; |
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35 | |
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36 | |
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37 | /** |
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38 | * An implementation of a Data View parser that stores the content of a Data |
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39 | * View in DOM representation. |
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40 | * |
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41 | * @see DataViewGenericDOM |
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42 | */ |
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43 | public class DataViewParserGenericDOM implements DataViewParser { |
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44 | private static class TransformHelper { |
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45 | private final DocumentBuilder builder; |
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46 | private final Transformer transformer; |
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47 | |
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48 | |
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49 | private TransformHelper(DocumentBuilder builder, |
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50 | Transformer transformer) { |
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51 | if (builder == null) { |
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52 | throw new NullPointerException("builder == null"); |
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53 | } |
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54 | this.builder = builder; |
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55 | if (transformer == null) { |
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56 | throw new NullPointerException("transformer == null"); |
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57 | } |
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58 | this.transformer = transformer; |
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59 | } |
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60 | |
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61 | |
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62 | private Document transform(XMLStreamReader reader) |
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63 | throws XMLStreamException, TransformerException { |
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64 | // parse STAX to DOM fragment |
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65 | Document document = builder.newDocument(); |
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66 | DOMResult result = new DOMResult(document); |
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67 | transformer.transform(new StAXSource(reader), result); |
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68 | return document; |
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69 | } |
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70 | |
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71 | |
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72 | private void reset() { |
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73 | builder.reset(); |
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74 | transformer.reset(); |
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75 | } |
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76 | } // private class TransformHelper |
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77 | private final ThreadLocal<TransformHelper> transformHelper; |
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78 | |
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79 | public DataViewParserGenericDOM() { |
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80 | final DocumentBuilderFactory builderFactory = |
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81 | DocumentBuilderFactory.newInstance(); |
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82 | final TransformerFactory transformerFactory = |
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83 | TransformerFactory.newInstance(); |
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84 | this.transformHelper = new ThreadLocal<TransformHelper>() { |
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85 | @Override |
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86 | protected TransformHelper initialValue() { |
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87 | try { |
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88 | return new TransformHelper(builderFactory.newDocumentBuilder(), |
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89 | transformerFactory.newTransformer()); |
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90 | } catch (TransformerConfigurationException e) { |
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91 | throw new InternalError("unexpected error creating new transformer"); |
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92 | } catch (ParserConfigurationException e) { |
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93 | throw new InternalError("unexpected error creating new document builder"); |
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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 | |
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99 | } |
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100 | |
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101 | |
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102 | @Override |
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103 | public boolean acceptType(String type) { |
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104 | return true; |
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105 | } |
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106 | |
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107 | |
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108 | @Override |
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109 | public int getPriority() { |
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110 | return Integer.MIN_VALUE; |
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111 | } |
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112 | |
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113 | |
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114 | @Override |
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115 | public DataView parse(XMLStreamReader reader, String type, String pid, |
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116 | String ref) throws XMLStreamException, SRUClientException { |
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117 | final TransformHelper helper = transformHelper.get(); |
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118 | try { |
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119 | final Document document = helper.transform(reader); |
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120 | final NodeList children = document.getChildNodes(); |
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121 | if ((children != null) && (children.getLength() > 0)) { |
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122 | return new DataViewGenericDOM(type, pid, ref, document); |
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123 | } else { |
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124 | throw new SRUClientException("element <DataView> does not " |
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125 | + "contain any nested elements"); |
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126 | } |
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127 | } catch (TransformerException e) { |
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128 | throw new SRUClientException("error while parsing dataview", e); |
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129 | } finally { |
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130 | helper.reset(); |
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131 | } |
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132 | } |
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133 | |
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134 | } // class DataViewParserGenericDOM |
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