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    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
    18  package org.apache.any23.extractor.html;
    19
    20  import org.apache.any23.extractor.ExtractionContext;
    21  import org.apache.any23.extractor.ExtractionException;
    22  import org.apache.any23.extractor.ExtractionParameters;
    23  import org.apache.any23.extractor.ExtractionResult;
    24  import org.apache.any23.extractor.ExtractorDescription;
    25  import org.apache.any23.rdf.Any23ValueFactoryWrapper;
    26  import org.apache.any23.vocab.FOAF;
    27  import org.apache.any23.vocab.XFN;
    28  import org.apache.any23.extractor.Extractor.TagSoupDOMExtractor;
    29  import org.eclipse.rdf4j.model.BNode;
    30  import org.eclipse.rdf4j.model.IRI;
    31  import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
    32  import org.eclipse.rdf4j.model.vocabulary.RDF;
    33  import org.w3c.dom.Document;
    34  import org.w3c.dom.Node;
    35
    36  import java.io.IOException;
    37  import java.util.Locale;
    38
    39  /**
    40   * Extractor for the <a href="http://microformats.org/wiki/xfn">XFN</a> microformat.
    41   *
    42   * @author Richard Cyganiak (richard@cyganiak.de)
    43   */
    44  public class XFNExtractor implements TagSoupDOMExtractor {
    45
    46      private static final FOAF vFOAF = FOAF.getInstance();
    47      private static final XFN vXFN = XFN.getInstance();
    48
    49      private final static Any23ValueFactoryWrapperAny23ValueFactoryWrapper">Any23ValueFactoryWrapper factoryWrapper = new Any23ValueFactoryWrapper(
    50              SimpleValueFactory.getInstance());
    51
    52      private HTMLDocument document;
    53      private ExtractionResult out;
    54
    55      @Override
    56      public ExtractorDescription getDescription() {
    57          return XFNExtractorFactory.getDescriptionInstance();
    58      }
    59
    60      @Override
    61      public void run(ExtractionParameters extractionParameters, ExtractionContext extractionContext, Document in,
    62              ExtractionResult out) throws IOException, ExtractionException {
    63          factoryWrapper.setIssueReport(out);
    64          try {
    65              document = new HTMLDocument(in);
    66              this.out = out;
    67
    68              BNode subject = factoryWrapper.createBNode();
    69              boolean foundAnyXFN = false;
    70              final IRI documentIRI = extractionContext.getDocumentIRI();
    71              for (Node link : document.findAll("//A[@rel][@href]")) {
    72                  foundAnyXFN |= extractLink(link, subject, documentIRI);
    73              }
    74              if (!foundAnyXFN)
    75                  return;
    76              out.writeTriple(subject, RDF.TYPE, vFOAF.Person);
    77              out.writeTriple(subject, vXFN.mePage, documentIRI);
    78          } finally {
    79              factoryWrapper.setIssueReport(null);
    80          }
    81      }
    82
    83      private boolean extractLink(Node firstLink, BNode subject, IRI documentIRI) throws ExtractionException {
    84          String href = firstLink.getAttributes().getNamedItem("href").getNodeValue();
    85          String rel = firstLink.getAttributes().getNamedItem("rel").getNodeValue();
    86
    87          String[] rels = rel.split("\\s+");
    88          IRI link = document.resolveIRI(href);
    89          if (containsRelMe(rels)) {
    90              if (containsXFNRelExceptMe(rels)) {
    91                  return false; // "me" cannot be combined with any other XFN values
    92              }
    93              out.writeTriple(subject, vXFN.mePage, link);
    94              out.writeTriple(documentIRI, vXFN.getExtendedProperty("me"), link);
    95          } else {
    96              BNode person2 = factoryWrapper.createBNode();
    97              boolean foundAnyXFNRel = false;
    98              for (String aRel : rels) {
    99                  foundAnyXFNRel |= extractRel(aRel, subject, documentIRI, person2, link);
    100             }
    101             if (!foundAnyXFNRel) {
    102                 return false;
    103             }
    104             out.writeTriple(person2, RDF.TYPE, vFOAF.Person);
    105             out.writeTriple(person2, vXFN.mePage, link);
    106         }
    107         return true;
    108     }
    109
    110     private boolean containsRelMe(String[] rels) {
    111         for (String rel : rels) {
    112             if ("me".equals(rel.toLowerCase(Locale.ROOT))) {
    113                 return true;
    114             }
    115         }
    116         return false;
    117     }
    118
    119     private boolean containsXFNRelExceptMe(String[] rels) {
    120         for (String rel : rels) {
    121             if (!"me".equals(rel.toLowerCase(Locale.ROOT)) && vXFN.isXFNLocalName(rel)) {
    122                 return true;
    123             }
    124         }
    125         return false;
    126     }
    127
    128     private boolean extractRel(String rel, BNode person1, IRI uri1, BNode person2, IRI uri2) {
    129         IRI peopleProp = vXFN.getPropertyByLocalName(rel);
    130         IRI hyperlinkProp = vXFN.getExtendedProperty(rel);
    131         if (peopleProp == null) {
    132             return false;
    133         }
    134         out.writeTriple(person1, peopleProp, person2);
    135         out.writeTriple(uri1, hyperlinkProp, uri2);
    136         return true;
    137     }
    138
    139 }