/*
 * 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.
 */

package org.apache.mahout.analysis;

import java.io.Reader;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.LowerCaseFilter;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.wikipedia.analysis.WikipediaTokenizer;

public class WikipediaAnalyzer extends Analyzer {
 
  private final CharArraySet stopSet;
  
  public WikipediaAnalyzer() {
    stopSet = (CharArraySet) StopFilter.makeStopSet(
        StopAnalyzer.ENGLISH_STOP_WORDS_SET.toArray(new String[StopAnalyzer.ENGLISH_STOP_WORDS_SET.size()]));
  }
  
  public WikipediaAnalyzer(CharArraySet stopSet) {
    this.stopSet = stopSet;
  }
  
  @Override
  public TokenStream tokenStream(String fieldName, Reader reader) {
    TokenStream result = new WikipediaTokenizer(reader);
    result = new StandardFilter(result);
    result = new LowerCaseFilter(result);
    result = new StopFilter(true, result, stopSet);
    return result;
  }
}
