/**
    * Copyright 2008-2010 Digital Enterprise Research Institute (DERI)
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *          http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  package org.deri.any23.extractor.html;
  
  import org.deri.any23.extractor.ExtractionContext;
  import org.deri.any23.extractor.ExtractionException;
  import org.deri.any23.extractor.ExtractionParameters;
  import org.deri.any23.extractor.ExtractionResult;
  import org.deri.any23.extractor.Extractor.TagSoupDOMExtractor;
  import org.deri.any23.extractor.ExtractorDescription;
  import org.deri.any23.extractor.ExtractorFactory;
  import org.deri.any23.extractor.SimpleExtractorFactory;
  import org.deri.any23.rdf.Any23ValueFactoryWrapper;
  import org.deri.any23.rdf.PopularPrefixes;
  import org.deri.any23.vocab.DCTERMS;
  import org.openrdf.model.impl.ValueFactoryImpl;
  import org.w3c.dom.Document;
  
  import java.io.IOException;
  import java.util.Arrays;
  
  /**
   * Extracts the value of the <title> element of an
   * HTML or XHTML page.
   *
   * @author Richard Cyganiak (richard@cyganiak.de)
   */
  public class TitleExtractor implements TagSoupDOMExtractor {
  
      public static final String NAME = "html-head-title";
  
      private static final DCTERMS vDCTERMS = DCTERMS.getInstance();
  
      public final static ExtractorFactory<TitleExtractor> factory =
              SimpleExtractorFactory.create(
                      NAME,
                      PopularPrefixes.createSubset("dcterms"),
                      Arrays.asList("text/html;q=0.02", "application/xhtml+xml;q=0.02"),
                      "example-title.html",
                      TitleExtractor.class
              );
  
      public void run(
              ExtractionParameters extractionParameters,
              ExtractionContext extractionContext,
              Document in,
              ExtractionResult out
      ) throws IOException, ExtractionException {
          final Any23ValueFactoryWrapper valueFactory = new Any23ValueFactoryWrapper(
              ValueFactoryImpl.getInstance(), out, extractionContext.getDefaultLanguage()
          );
          
          try {
              String title = DomUtils.find(in, "/HTML/HEAD/TITLE/text()").trim();
              if (title != null && (title.length() != 0)) {
                  out.writeTriple(extractionContext.getDocumentURI(), vDCTERMS.title, valueFactory.createLiteral(title));
              }
          } finally {
              valueFactory.setErrorReporter(null);
          }
      }
  
      public ExtractorDescription getDescription() {
          return factory;
      }
      
  }