PositionalPorterStopAnalyzer.java

package lia.analysis.positional;

/**
 * Copyright Manning Publications Co.
 *
 * 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 lan      
*/

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.LowerCaseTokenizer;
import org.apache.lucene.analysis.PorterStemFilter;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;

import java.io.Reader;
import java.util.Set;

// From chapter 4
public class PositionalPorterStopAnalyzer extends Analyzer {
  private Set stopWords;

  public PositionalPorterStopAnalyzer() {
    this(StopAnalyzer.ENGLISH_STOP_WORDS_SET);
  }

  public PositionalPorterStopAnalyzer(Set stopWords) {
    this.stopWords = stopWords;
  }

  public TokenStream tokenStream(String fieldName, Reader reader) {
    StopFilter stopFilter = new StopFilter(true,
                                           new LowerCaseTokenizer(reader),
                                           stopWords);
    stopFilter.setEnablePositionIncrements(true);
    return new PorterStemFilter(stopFilter);
  }
}