Lucene example source code file (CJKAnalyzer.java)

This example Lucene source code file (CJKAnalyzer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

cjkanalyzer, cjkanalyzer, default_stop_set, deprecated, io, reader, set, set, stopfilter, stopwordanalyzerbase, string, string, tokenizer, tokenstreamcomponents, tokenstreamcomponents, util

The Lucene CJKAnalyzer.java source code

package org.apache.lucene.analysis.cjk;

/**
 * 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.Analyzer;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.StopwordAnalyzerBase;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.util.Version;

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


/**
 * An {@link Analyzer} that tokenizes text with {@link CJKTokenizer} and
 * filters with {@link StopFilter}
 *
 */
public final class CJKAnalyzer extends StopwordAnalyzerBase {
  //~ Static fields/initializers ---------------------------------------------

  /**
   * An array containing some common English words that are not usually
   * useful for searching and some double-byte interpunctions.
   * @deprecated use {@link #getDefaultStopSet()} instead
   */
  @Deprecated
  public final static 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", "",
    "www"
  };

  //~ Instance fields --------------------------------------------------------

  /**
   * Returns an unmodifiable instance of the default stop-words set.
   * @return an unmodifiable instance of the default stop-words set.
   */
  public static Set<?> getDefaultStopSet(){
    return DefaultSetHolder.DEFAULT_STOP_SET;
  }
  
  private static class DefaultSetHolder {
    static final Set<?> DEFAULT_STOP_SET = CharArraySet
        .unmodifiableSet(new CharArraySet(Version.LUCENE_CURRENT, Arrays.asList(STOP_WORDS),
            false));
  }

  //~ Constructors -----------------------------------------------------------

  /**
   * Builds an analyzer which removes words in {@link #getDefaultStopSet()}.
   */
  public CJKAnalyzer(Version matchVersion) {
    this(matchVersion, DefaultSetHolder.DEFAULT_STOP_SET);
  }
  
  /**
   * Builds an analyzer with the given stop words
   * 
   * @param matchVersion
   *          lucene compatibility version
   * @param stopwords
   *          a stopword set
   */
  public CJKAnalyzer(Version matchVersion, Set<?> stopwords){
    super(matchVersion, stopwords);
  }

  /**
   * Builds an analyzer which removes words in the provided array.
   *
   * @param stopWords stop word array
   * @deprecated use {@link #CJKAnalyzer(Version, Set)} instead
   */
  @Deprecated
  public CJKAnalyzer(Version matchVersion, String... stopWords) {
    super(matchVersion, StopFilter.makeStopSet(matchVersion, stopWords));
  }

  //~ Methods ----------------------------------------------------------------

  @Override
  protected TokenStreamComponents createComponents(String fieldName,
      Reader reader) {
    final Tokenizer source = new CJKTokenizer(reader);
    return new TokenStreamComponents(source, new StopFilter(matchVersion, source, stopwords));
  }
}