content: package org.apache.lucene.analysis.cz;
  
  /**
   * 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.ReusableAnalyzerBase;
  import org.apache.lucene.analysis.Analyzer;
  import org.apache.lucene.analysis.CharArraySet;
  import org.apache.lucene.analysis.KeywordMarkerFilter;
  import org.apache.lucene.analysis.LowerCaseFilter;
  import org.apache.lucene.analysis.StopFilter;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.Tokenizer;
  import org.apache.lucene.analysis.WordlistLoader;
  import org.apache.lucene.analysis.standard.StandardFilter;
  import org.apache.lucene.analysis.standard.StandardTokenizer;
  import org.apache.lucene.util.IOUtils;
  import org.apache.lucene.util.Version;
  
  import java.io.*;
  import java.nio.charset.Charset;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * {@link Analyzer} for Czech language.
   * <p>
   * Supports an external list of stopwords (words that will not be indexed at
   * all). A default set of stopwords is used unless an alternative list is
   * specified.
   * </p>
   * 
   * <a name="version"/>
   * <p>
   * You must specify the required {@link Version} compatibility when creating
   * CzechAnalyzer:
   * <ul>
   * <li>As of 3.1, words are stemmed with {@link CzechStemFilter}
   * <li>As of 2.9, StopFilter preserves position increments
   * <li>As of 2.4, Tokens incorrectly identified as acronyms are corrected (see
   * <a href="https://issues.apache.org/jira/browse/LUCENE-1068">LUCENE-1068</a>)
   * </ul>
   */
  public final class CzechAnalyzer extends ReusableAnalyzerBase {
  
    /**
  	 * List of typical stopwords.
  	 * @deprecated use {@link #getDefaultStopSet()} instead
  	 */
  	@Deprecated
  	public final static String[] CZECH_STOP_WORDS = {
          "a","s","k","o","i","u","v","z","dnes","cz","t\u00edmto","bude\u0161","budem",
          "byli","jse\u0161","m\u016fj","sv\u00fdm","ta","tomto","tohle","tuto","tyto",
          "jej","zda","pro\u010d","m\u00e1te","tato","kam","tohoto","kdo","kte\u0159\u00ed",
          "mi","n\u00e1m","tom","tomuto","m\u00edt","nic","proto","kterou","byla",
          "toho","proto\u017ee","asi","ho","na\u0161i","napi\u0161te","re","co\u017e","t\u00edm",
          "tak\u017ee","sv\u00fdch","jej\u00ed","sv\u00fdmi","jste","aj","tu","tedy","teto",
          "bylo","kde","ke","prav\u00e9","ji","nad","nejsou","\u010di","pod","t\u00e9ma",
          "mezi","p\u0159es","ty","pak","v\u00e1m","ani","kdy\u017e","v\u0161ak","neg","jsem",
          "tento","\u010dl\u00e1nku","\u010dl\u00e1nky","aby","jsme","p\u0159ed","pta","jejich",
          "byl","je\u0161t\u011b","a\u017e","bez","tak\u00e9","pouze","prvn\u00ed","va\u0161e","kter\u00e1",
          "n\u00e1s","nov\u00fd","tipy","pokud","m\u016f\u017ee","strana","jeho","sv\u00e9","jin\u00e9",
          "zpr\u00e1vy","nov\u00e9","nen\u00ed","v\u00e1s","jen","podle","zde","u\u017e","b\u00fdt","v\u00edce",
          "bude","ji\u017e","ne\u017e","kter\u00fd","by","kter\u00e9","co","nebo","ten","tak",
          "m\u00e1","p\u0159i","od","po","jsou","jak","dal\u0161\u00ed","ale","si","se","ve",
          "to","jako","za","zp\u011bt","ze","do","pro","je","na","atd","atp",
          "jakmile","p\u0159i\u010dem\u017e","j\u00e1","on","ona","ono","oni","ony","my","vy",
          "j\u00ed","ji","m\u011b","mne","jemu","tomu","t\u011bm","t\u011bmu","n\u011bmu","n\u011bmu\u017e",
          "jeho\u017e","j\u00ed\u017e","jeliko\u017e","je\u017e","jako\u017e","na\u010de\u017e",
      };
  	
    /** File containing default Czech stopwords. */
    public final static String DEFAULT_STOPWORD_FILE = "stopwords.txt";
    
    /**
     * Returns a set of default Czech-stopwords
     * 
     * @return a set of default Czech-stopwords
     */
  	public static final Set<?> getDefaultStopSet(){
  	  return DefaultSetHolder.DEFAULT_SET;
  	}
  	
  	private static class DefaultSetHolder {
  	  private static final Set<?> DEFAULT_SET;
  	  
  	  static {
  	    try {
  	      DEFAULT_SET = WordlistLoader.getWordSet(IOUtils.getDecodingReader(CzechAnalyzer.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");
  	    }
  	  }
  	}
  
   
    /**
     * Contains the stopwords used with the {@link StopFilter}.
     */
  	// TODO once loadStopWords is gone those member should be removed too in favor of StopwordAnalyzerBase
  	private Set<?> stoptable;
    private final Version matchVersion;
    private final Set<?> stemExclusionTable;
  
    /**
     * Builds an analyzer with the default stop words ({@link #getDefaultStopSet()}).
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     */
  	public CzechAnalyzer(Version matchVersion) {
      this(matchVersion, DefaultSetHolder.DEFAULT_SET);
  	}
  	
    /**
     * Builds an analyzer with the given stop words.
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     * @param stopwords a stopword set
     */
    public CzechAnalyzer(Version matchVersion, Set<?> stopwords) {
      this(matchVersion, stopwords, CharArraySet.EMPTY_SET);
    }
    
    /**
     * Builds an analyzer with the given stop words and a set of work to be
     * excluded from the {@link CzechStemFilter}.
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     * @param stopwords a stopword set
     * @param stemExclusionTable a stemming exclusion set
     */
    public CzechAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionTable) {
      this.matchVersion = matchVersion;
      this.stoptable = CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion, stopwords));
      this.stemExclusionTable = CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion, stemExclusionTable));
    }
  
  
    /**
     * Builds an analyzer with the given stop words.
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     * @param stopwords a stopword set
     * @deprecated use {@link #CzechAnalyzer(Version, Set)} instead
     */
    @Deprecated
    public CzechAnalyzer(Version matchVersion, String... stopwords) {
      this(matchVersion, StopFilter.makeStopSet( matchVersion, stopwords ));
  	}
  
    /**
     * Builds an analyzer with the given stop words.
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     * @param stopwords a stopword set
     * @deprecated use {@link #CzechAnalyzer(Version, Set)} instead
     */
    @Deprecated
    public CzechAnalyzer(Version matchVersion, HashSet<?> stopwords) {
      this(matchVersion, (Set<?>)stopwords);
  	}
  
    /**
     * Builds an analyzer with the given stop words.
     * 
     * @param matchVersion Lucene version to match See
     *          {@link <a href="#version">above</a>}
     * @param stopwords a file containing stopwords
     * @deprecated use {@link #CzechAnalyzer(Version, Set)} instead
     */
    @Deprecated
    public CzechAnalyzer(Version matchVersion, File stopwords ) throws IOException {
      this(matchVersion, (Set<?>)WordlistLoader.getWordSet(
          IOUtils.getDecodingReader(stopwords, IOUtils.CHARSET_UTF_8), matchVersion));
  	}
  
      /**
       * Loads stopwords hash from resource stream (file, database...).
       * @param   wordfile    File containing the wordlist
       * @param   encoding    Encoding used (win-1250, iso-8859-2, ...), null for default system encoding
       * @deprecated use {@link WordlistLoader#getWordSet(Reader, String, Version) }
       *             and {@link #CzechAnalyzer(Version, Set)} instead
       */
      // TODO extend StopwordAnalyzerBase once this method is gone!
      @Deprecated
      public void loadStopWords( InputStream wordfile, String encoding ) {
          setPreviousTokenStream(null); // force a new stopfilter to be created
          if ( wordfile == null ) {
              stoptable = CharArraySet.EMPTY_SET;
              return;
          }
          try {
              // clear any previous table (if present)
              stoptable = CharArraySet.EMPTY_SET;
              stoptable = WordlistLoader.getWordSet(IOUtils.getDecodingReader(wordfile, 
                  encoding == null ? IOUtils.CHARSET_UTF_8 : Charset.forName(encoding)), matchVersion);
          } catch ( IOException e ) {
            // clear any previous table (if present)
            // TODO: throw IOException
            stoptable = Collections.emptySet();
          }
      }
  
    /**
     * 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 LowerCaseFilter}, {@link StopFilter}
     *         , and {@link CzechStemFilter} (only if version is >= LUCENE_31). If
     *         a version is >= LUCENE_31 and a stem exclusion set is provided via
     *         {@link #CzechAnalyzer(Version, Set, Set)} a
     *         {@link KeywordMarkerFilter} is added before
     *         {@link CzechStemFilter}.
     */
    @Override
    protected TokenStreamComponents createComponents(String fieldName,
        Reader reader) {
      final Tokenizer source = new StandardTokenizer(matchVersion, reader);
      TokenStream result = new StandardFilter(matchVersion, source);
      result = new LowerCaseFilter(matchVersion, result);
      result = new StopFilter( matchVersion, result, stoptable);
      if (matchVersion.onOrAfter(Version.LUCENE_31)) {
        if(!this.stemExclusionTable.isEmpty())
          result = new KeywordMarkerFilter(result, stemExclusionTable);
        result = new CzechStemFilter(result);
      }
      return new TokenStreamComponents(source, result);
    }
  }
  
  