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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.vocab.XHTML;
    26  import org.apache.any23.extractor.Extractor.TagSoupDOMExtractor;
    27  import org.eclipse.rdf4j.model.IRI;
    28  import org.eclipse.rdf4j.model.ValueFactory;
    29  import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
    30  import org.w3c.dom.Document;
    31  import org.w3c.dom.Node;
    32
    33  import java.io.IOException;
    34  import java.util.List;
    35
    36  /**
    37   * This {@link org.apache.any23.extractor.Extractor.TagSoupDOMExtractor} implementation retrieves the <code>LINK</code>s
    38   * declared within the <code>HTML/HEAD</code> page header.
    39   */
    40  public class HeadLinkExtractor implements TagSoupDOMExtractor {
    41
    42      public void run(ExtractionParameters extractionParameters, ExtractionContext extractionContext, Document in,
    43              ExtractionResult out) throws IOException, ExtractionException {
    44          HTMLDocument html = new HTMLDocument(in);
    45          ValueFactory vf = SimpleValueFactory.getInstance();
    46
    47          final List<Node> headLinkNodes = DomUtils.findAll(in,
    48                  "/HTML/HEAD/LINK[(" + "@type='application/rdf+xml' or " + "@type='text/rdf' or "
    49                          + "@type='application/x-turtle' or " + "@type='application/turtle' or "
    50                          + "@type='text/turtle' or " + "@type='text/rdf+n3'" + ") and @href and @rel]");
    51          for (Node node : headLinkNodes) {
    52              final IRI href = html.resolveIRI(DomUtils.find(node, "@href"));
    53              final String rel = DomUtils.find(node, "@rel");
    54              out.writeTriple(extractionContext.getDocumentIRI(), vf.createIRI(XHTML.NS + rel), href);
    55              final String title = DomUtils.find(node, "@title");
    56              if (title != null && !"".equals(title)) {
    57                  out.writeTriple(href, getDescription().getPrefixes().expand("dcterms:title"), vf.createLiteral(title));
    58              }
    59              final String type = DomUtils.find(node, "@type");
    60              if (type != null && !"".equals(type)) {
    61                  out.writeTriple(href, getDescription().getPrefixes().expand("dcterms:format"), vf.createLiteral(type));
    62              }
    63          }
    64      }
    65
    66      @Override
    67      public ExtractorDescription getDescription() {
    68          return HeadLinkExtractorFactory.getDescriptionInstance();
    69      }
    70
    71  }