content: package org.apache.lucene.analysis.snowball;
  
  /**
   * 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.*;
  import org.apache.lucene.analysis.en.EnglishPossessiveFilter;
  import org.apache.lucene.analysis.standard.*;
  import org.apache.lucene.analysis.tr.TurkishLowerCaseFilter;
  import org.apache.lucene.util.Version;
  
  import java.io.IOException;
  import java.io.Reader;
  import java.util.Set;
  
  /** Filters {@link StandardTokenizer} with {@link StandardFilter}, {@link
   * LowerCaseFilter}, {@link StopFilter} and {@link SnowballFilter}.
   *
   * Available stemmers are listed in org.tartarus.snowball.ext.  The name of a
   * stemmer is the part of the class name before "Stemmer", e.g., the stemmer in
   * {@link org.tartarus.snowball.ext.EnglishStemmer} is named "English".
   *
   * <p><b>NOTE</b>: This class uses the same {@link Version}
   * dependent settings as {@link StandardAnalyzer}, with the following addition:
   * <ul>
   *   <li> As of 3.1, uses {@link TurkishLowerCaseFilter} for Turkish language.
   * </ul>
   * </p>
   * @deprecated Use the language-specific analyzer in contrib/analyzers instead. 
   * This analyzer will be removed in Lucene 5.0
   */
  @Deprecated
  public final class SnowballAnalyzer extends Analyzer {
    private String name;
    private Set<?> stopSet;
    private final Version matchVersion;
  
    /** Builds the named analyzer with no stop words. */
    public SnowballAnalyzer(Version matchVersion, String name) {
      this.name = name;
      this.matchVersion = matchVersion;
    }
  
    /** 
     * Builds the named analyzer with the given stop words.
     * @deprecated Use {@link #SnowballAnalyzer(Version, String, Set)} instead.  
     */
    @Deprecated
    public SnowballAnalyzer(Version matchVersion, String name, String[] stopWords) {
      this(matchVersion, name);
      stopSet = StopFilter.makeStopSet(matchVersion, stopWords);
    }
    
    /** Builds the named analyzer with the given stop words. */
    public SnowballAnalyzer(Version matchVersion, String name, Set<?> stopWords) {
      this(matchVersion, name);
      stopSet = CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion,
          stopWords));
    }
  
    /** Constructs a {@link StandardTokenizer} filtered by a {@link
        StandardFilter}, a {@link LowerCaseFilter}, a {@link StopFilter},
        and a {@link SnowballFilter} */
    @Override
    public TokenStream tokenStream(String fieldName, Reader reader) {
      TokenStream result = new StandardTokenizer(matchVersion, reader);
      result = new StandardFilter(matchVersion, result);
      // remove the possessive 's for english stemmers
      if (matchVersion.onOrAfter(Version.LUCENE_31) && 
          (name.equals("English") || name.equals("Porter") || name.equals("Lovins")))
        result = new EnglishPossessiveFilter(result);
      // Use a special lowercase filter for turkish, the stemmer expects it.
      if (matchVersion.onOrAfter(Version.LUCENE_31) && name.equals("Turkish"))
        result = new TurkishLowerCaseFilter(result);
      else
        result = new LowerCaseFilter(matchVersion, result);
      if (stopSet != null)
        result = new StopFilter(matchVersion,
                                result, stopSet);
      result = new SnowballFilter(result, name);
      return result;
    }
    
    private class SavedStreams {
      Tokenizer source;
      TokenStream result;
    }
    
    /** Returns a (possibly reused) {@link StandardTokenizer} filtered by a 
     * {@link StandardFilter}, a {@link LowerCaseFilter}, 
     * a {@link StopFilter}, and a {@link SnowballFilter} */
    @Override
    public TokenStream reusableTokenStream(String fieldName, Reader reader)
        throws IOException {
      SavedStreams streams = (SavedStreams) getPreviousTokenStream();
      if (streams == null) {
        streams = new SavedStreams();
        streams.source = new StandardTokenizer(matchVersion, reader);
        streams.result = new StandardFilter(matchVersion, streams.source);
        // Use a special lowercase filter for turkish, the stemmer expects it.
        if (matchVersion.onOrAfter(Version.LUCENE_31) && name.equals("Turkish"))
          streams.result = new TurkishLowerCaseFilter(streams.result);
        else
          streams.result = new LowerCaseFilter(matchVersion, streams.result);
        if (stopSet != null)
          streams.result = new StopFilter(matchVersion,
                                          streams.result, stopSet);
        streams.result = new SnowballFilter(streams.result, name);
        setPreviousTokenStream(streams);
      } else {
        streams.source.reset(reader);
      }
      return streams.result;
    }
  }
  