content: package org.apache.lucene.analysis.nl;
  
  /**
   * 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 java.io.IOException;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.lucene.analysis.KeywordMarkerFilter;// for javadoc
  import org.apache.lucene.analysis.TokenFilter;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.snowball.SnowballFilter;
  import org.apache.lucene.analysis.tokenattributes.KeywordAttribute;
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  
  /**
   * A {@link TokenFilter} that stems Dutch words. 
   * <p>
   * It supports a table of words that should
   * not be stemmed at all. The stemmer used can be changed at runtime after the
   * filter object is created (as long as it is a {@link DutchStemmer}).
   * </p>
   * <p>
   * To prevent terms from being stemmed use an instance of
   * {@link KeywordMarkerFilter} or a custom {@link TokenFilter} that sets
   * the {@link KeywordAttribute} before this {@link TokenStream}.
   * </p>
   * @see KeywordMarkerFilter
   * @deprecated Use {@link SnowballFilter} with 
   * {@link org.tartarus.snowball.ext.DutchStemmer} instead, which has the
   * same functionality. This filter will be removed in Lucene 5.0
   */
  @Deprecated
  public final class DutchStemFilter extends TokenFilter {
    /**
     * The actual token in the input stream.
     */
    private DutchStemmer stemmer = new DutchStemmer();
    private Set<?> exclusions = null;
    
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private final KeywordAttribute keywordAttr = addAttribute(KeywordAttribute.class);
  
    public DutchStemFilter(TokenStream _in) {
      super(_in);
    }
  
    /**
     * Builds a DutchStemFilter that uses an exclusion table.
     * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
     */
    @Deprecated
    public DutchStemFilter(TokenStream _in, Set<?> exclusiontable) {
      this(_in);
      exclusions = exclusiontable;
    }
    
    /**
     * @param stemdictionary Dictionary of word stem pairs, that overrule the algorithm
     */
    public DutchStemFilter(TokenStream _in,  Map<?,?> stemdictionary) {
      this(_in);
      stemmer.setStemDictionary(stemdictionary);
    }
  
    /**
     * @param stemdictionary Dictionary of word stem pairs, that overrule the algorithm
     * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
     */
    @Deprecated
    public DutchStemFilter(TokenStream _in, Set<?> exclusiontable, Map<?,?> stemdictionary) {
      this(_in, exclusiontable);
      stemmer.setStemDictionary(stemdictionary);
    }
  
    /**
     * Returns the next token in the stream, or null at EOS
     */
    @Override
    public boolean incrementToken() throws IOException {
      if (input.incrementToken()) {
        final String term = termAtt.toString();
  
        // Check the exclusion table.
        if (!keywordAttr.isKeyword() && (exclusions == null || !exclusions.contains(term))) {
          final String s = stemmer.stem(term);
          // If not stemmed, don't waste the time adjusting the token.
          if ((s != null) && !s.equals(term))
            termAtt.setEmpty().append(s);
        }
        return true;
      } else {
        return false;
      }
    }
  
    /**
     * Set a alternative/custom {@link DutchStemmer} for this filter.
     */
    public void setStemmer(DutchStemmer stemmer) {
      if (stemmer != null) {
        this.stemmer = stemmer;
      }
    }
  
    /**
     * Set an alternative exclusion list for this filter.
     * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
     */
    @Deprecated
    public void setExclusionTable(HashSet<?> exclusiontable) {
      exclusions = exclusiontable;
    }
  
    /**
     * Set dictionary for stemming, this dictionary overrules the algorithm,
     * so you can correct for a particular unwanted word-stem pair.
     */
    public void setStemDictionary(HashMap<?,?> dict) {
      if (stemmer != null)
        stemmer.setStemDictionary(dict);
    }
  }