content: package org.apache.lucene.analysis.fr;
  
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
   */
  
  import org.apache.lucene.analysis.Analyzer;
  import org.apache.lucene.analysis.CharArraySet;
  import org.apache.lucene.analysis.LowerCaseFilter;
  import org.apache.lucene.analysis.KeywordMarkerFilter;
  import org.apache.lucene.analysis.StopFilter;
  import org.apache.lucene.analysis.StopwordAnalyzerBase;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.Tokenizer;
  import org.apache.lucene.analysis.WordlistLoader;
  import org.apache.lucene.analysis.snowball.SnowballFilter;
  import org.apache.lucene.analysis.standard.StandardFilter;
  import org.apache.lucene.analysis.standard.StandardTokenizer;
  import org.apache.lucene.analysis.standard.StandardAnalyzer;  // for javadoc
  import org.apache.lucene.util.IOUtils;
  import org.apache.lucene.util.Version;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.Reader;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Collections;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * {@link Analyzer} for French language. 
   * <p>
   * Supports an external list of stopwords (words that
   * will not be indexed at all) and an external list of exclusions (word that will
   * not be stemmed, but indexed).
   * A default set of stopwords is used unless an alternative list is specified, but the
   * exclusion list is empty by default.
   * </p>
   *
   * <a name="version"/>
   * <p>You must specify the required {@link Version}
   * compatibility when creating FrenchAnalyzer:
   * <ul>
   *   <li> As of 3.1, Snowball stemming is done with SnowballFilter, 
   *        LowerCaseFilter is used prior to StopFilter, and ElisionFilter and 
   *        Snowball stopwords are used by default.
   *   <li> As of 2.9, StopFilter preserves position
   *        increments
   * </ul>
   *
   * <p><b>NOTE</b>: This class uses the same {@link Version}
   * dependent settings as {@link StandardAnalyzer}.</p>
   */
  public final class FrenchAnalyzer extends StopwordAnalyzerBase {
  
    /**
     * Extended list of typical French stopwords.
     * @deprecated use {@link #getDefaultStopSet()} instead
     */
    @Deprecated
    public final static String[] FRENCH_STOP_WORDS = {
      "a", "afin", "ai", "ainsi", "après", "attendu", "au", "aujourd", "auquel", "aussi",
      "autre", "autres", "aux", "auxquelles", "auxquels", "avait", "avant", "avec", "avoir",
      "c", "car", "ce", "ceci", "cela", "celle", "celles", "celui", "cependant", "certain",
      "certaine", "certaines", "certains", "ces", "cet", "cette", "ceux", "chez", "ci",
      "combien", "comme", "comment", "concernant", "contre", "d", "dans", "de", "debout",
      "dedans", "dehors", "delà", "depuis", "derrière", "des", "désormais", "desquelles",
      "desquels", "dessous", "dessus", "devant", "devers", "devra", "divers", "diverse",
      "diverses", "doit", "donc", "dont", "du", "duquel", "durant", "dès", "elle", "elles",
      "en", "entre", "environ", "est", "et", "etc", "etre", "eu", "eux", "excepté", "hormis",
      "hors", "hélas", "hui", "il", "ils", "j", "je", "jusqu", "jusque", "l", "la", "laquelle",
      "le", "lequel", "les", "lesquelles", "lesquels", "leur", "leurs", "lorsque", "lui", "là",
      "ma", "mais", "malgré", "me", "merci", "mes", "mien", "mienne", "miennes", "miens", "moi",
      "moins", "mon", "moyennant", "même", "mêmes", "n", "ne", "ni", "non", "nos", "notre",
      "nous", "néanmoins", "nôtre", "nôtres", "on", "ont", "ou", "outre", "où", "par", "parmi",
      "partant", "pas", "passé", "pendant", "plein", "plus", "plusieurs", "pour", "pourquoi",
      "proche", "près", "puisque", "qu", "quand", "que", "quel", "quelle", "quelles", "quels",
      "qui", "quoi", "quoique", "revoici", "revoilà", "s", "sa", "sans", "sauf", "se", "selon",
      "seront", "ses", "si", "sien", "sienne", "siennes", "siens", "sinon", "soi", "soit",
      "son", "sont", "sous", "suivant", "sur", "ta", "te", "tes", "tien", "tienne", "tiennes",
      "tiens", "toi", "ton", "tous", "tout", "toute", "toutes", "tu", "un", "une", "va", "vers",
      "voici", "voilà", "vos", "votre", "vous", "vu", "vôtre", "vôtres", "y", "à", "ça", "ès",
      "été", "être", "ô"
    };
  
    /** File containing default French stopwords. */
    public final static String DEFAULT_STOPWORD_FILE = "french_stop.txt";
    
    /**
     * Contains words that should be indexed but not stemmed.
     */
    private Set<?> excltable = CharArraySet.EMPTY_SET;
  
    /**
     * Returns an unmodifiable instance of the default stop-words set.
     * @return an unmodifiable instance of the default stop-words set.
     */
    public static Set<?> getDefaultStopSet(){
      return DefaultSetHolder.DEFAULT_STOP_SET;
    }
    
    private static class DefaultSetHolder {
      /** @deprecated remove this in Lucene 5.0 */
      @Deprecated
      static final Set<?> DEFAULT_STOP_SET_30 = CharArraySet
          .unmodifiableSet(new CharArraySet(Version.LUCENE_CURRENT, Arrays.asList(FRENCH_STOP_WORDS),
              false));
      static final Set<?> DEFAULT_STOP_SET;
      static {
        try {
          DEFAULT_STOP_SET = WordlistLoader.getSnowballWordSet(IOUtils.getDecodingReader(SnowballFilter.class, 
                  DEFAULT_STOPWORD_FILE, IOUtils.CHARSET_UTF_8), Version.LUCENE_CURRENT);
        } catch (IOException ex) {
          // default set should always be present as it is part of the
          // distribution (JAR)
          throw new RuntimeException("Unable to load default stopword set");
        }
      }
    }
  
    /**
     * Builds an analyzer with the default stop words ({@link #getDefaultStopSet}).
     */
    public FrenchAnalyzer(Version matchVersion) {
      this(matchVersion,
          matchVersion.onOrAfter(Version.LUCENE_31) ? DefaultSetHolder.DEFAULT_STOP_SET
              : DefaultSetHolder.DEFAULT_STOP_SET_30);
    }
    
    /**
     * Builds an analyzer with the given stop words
     * 
     * @param matchVersion
     *          lucene compatibility version
     * @param stopwords
     *          a stopword set
     */
    public FrenchAnalyzer(Version matchVersion, Set<?> stopwords){
      this(matchVersion, stopwords, CharArraySet.EMPTY_SET);
    }
    
    /**
     * Builds an analyzer with the given stop words
     * 
     * @param matchVersion
     *          lucene compatibility version
     * @param stopwords
     *          a stopword set
     * @param stemExclutionSet
     *          a stemming exclusion set
     */
    public FrenchAnalyzer(Version matchVersion, Set<?> stopwords,
        Set<?> stemExclutionSet) {
      super(matchVersion, stopwords);
      this.excltable = CharArraySet.unmodifiableSet(CharArraySet
          .copy(matchVersion, stemExclutionSet));
    }
   
  
    /**
     * Builds an analyzer with the given stop words.
     * @deprecated use {@link #FrenchAnalyzer(Version, Set)} instead
     */
    @Deprecated
    public FrenchAnalyzer(Version matchVersion, String... stopwords) {
      this(matchVersion, StopFilter.makeStopSet(matchVersion, stopwords));
    }
  
    /**
     * Builds an analyzer with the given stop words.
     * @throws IOException
     * @deprecated use {@link #FrenchAnalyzer(Version, Set)} instead
     */
    @Deprecated
    public FrenchAnalyzer(Version matchVersion, File stopwords) throws IOException {
      this(matchVersion, WordlistLoader.getWordSet(IOUtils.getDecodingReader(stopwords,
          IOUtils.CHARSET_UTF_8), matchVersion));
    }
  
    /**
     * Builds an exclusionlist from an array of Strings.
     * @deprecated use {@link #FrenchAnalyzer(Version, Set, Set)} instead
     */
    @Deprecated
    public void setStemExclusionTable(String... exclusionlist) {
      excltable = StopFilter.makeStopSet(matchVersion, exclusionlist);
      setPreviousTokenStream(null); // force a new stemmer to be created
    }
  
    /**
     * Builds an exclusionlist from a Map.
     * @deprecated use {@link #FrenchAnalyzer(Version, Set, Set)} instead
     */
    @Deprecated
    public void setStemExclusionTable(Map<?,?> exclusionlist) {
      excltable = new HashSet<Object>(exclusionlist.keySet());
      setPreviousTokenStream(null); // force a new stemmer to be created
    }
  
    /**
     * Builds an exclusionlist from the words contained in the given file.
     * @throws IOException
     * @deprecated use {@link #FrenchAnalyzer(Version, Set, Set)} instead
     */
    @Deprecated
    public void setStemExclusionTable(File exclusionlist) throws IOException {
      excltable = WordlistLoader.getWordSet(IOUtils.getDecodingReader(exclusionlist,
          IOUtils.CHARSET_UTF_8), matchVersion);
      setPreviousTokenStream(null); // force a new stemmer to be created
    }
  
    /**
     * Creates
     * {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
     * used to tokenize all the text in the provided {@link Reader}.
     * 
     * @return {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
     *         built from a {@link StandardTokenizer} filtered with
     *         {@link StandardFilter}, {@link ElisionFilter},
     *         {@link LowerCaseFilter}, {@link StopFilter},
     *         {@link KeywordMarkerFilter} if a stem exclusion set is
     *         provided, and {@link SnowballFilter}
     */
    @Override
    protected TokenStreamComponents createComponents(String fieldName,
        Reader reader) {
      if (matchVersion.onOrAfter(Version.LUCENE_31)) {
        final Tokenizer source = new StandardTokenizer(matchVersion, reader);
        TokenStream result = new StandardFilter(matchVersion, source);
        result = new ElisionFilter(matchVersion, result);
        result = new LowerCaseFilter(matchVersion, result);
        result = new StopFilter(matchVersion, result, stopwords);
        if(!excltable.isEmpty())
          result = new KeywordMarkerFilter(result, excltable);
        result = new SnowballFilter(result, new org.tartarus.snowball.ext.FrenchStemmer());
        return new TokenStreamComponents(source, result);
      } else {
        final Tokenizer source = new StandardTokenizer(matchVersion, reader);
        TokenStream result = new StandardFilter(matchVersion, source);
        result = new StopFilter(matchVersion, result, stopwords);
        if(!excltable.isEmpty())
          result = new KeywordMarkerFilter(result, excltable);
        result = new FrenchStemFilter(result);
        // Convert to lowercase after stemming!
        return new TokenStreamComponents(source, new LowerCaseFilter(matchVersion, result));
      }
    }
  }
  
  