src/java/org/apache/lucene/analysis/standard/StandardAnalyzer.java

package org.apache.lucene.analysis.standard;

/* ====================================================================
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 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import org.apache.lucene.analysis.*;
import java.io.Reader;
import java.util.Hashtable;

/** Filters {@link StandardTokenizer} with {@link StandardFilter}, {@link
 * LowerCaseFilter} and {@link StopFilter}. */
public final class StandardAnalyzer extends Analyzer {
  private Hashtable stopTable;

  /** An array containing some common English words that are not usually useful
    for searching. */
  public static final String[] STOP_WORDS = {
    "a", "and", "are", "as", "at", "be", "but", "by",
    "for", "if", "in", "into", "is", "it",
    "no", "not", "of", "on", "or", "s", "such",
    "t", "that", "the", "their", "then", "there", "these",
    "they", "this", "to", "was", "will", "with"
  };

  /** Builds an analyzer. */
  public StandardAnalyzer() {
    this(STOP_WORDS);
  }

  /** Builds an analyzer with the given stop words. */
  public StandardAnalyzer(String[] stopWords) {
    stopTable = StopFilter.makeStopTable(stopWords);
  }

  /** Constructs a {@link StandardTokenizer} filtered by a {@link
   * StandardFilter}, a {@link LowerCaseFilter} and a {@link StopFilter}. */
  public final TokenStream tokenStream(String fieldName, Reader reader) {
    TokenStream result = new StandardTokenizer(reader);
    result = new StandardFilter(result);
    result = new LowerCaseFilter(result);
    result = new StopFilter(result, stopTable);
    return result;
  }
}