Lucene example source code file (TestKStemmer.java)

This example Lucene source code file (TestKStemmer.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

analyzer, basetokenstreamtestcase, exception, exception, io, mocktokenizer, override, reader, reader, reusableanalyzerbase, reusableanalyzerbase, testkstemmer, tokenizer, tokenstreamcomponents, tokenstreamcomponents

The Lucene TestKStemmer.java source code

package org.apache.lucene.analysis.en;

/**
 * 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 static org.apache.lucene.analysis.VocabularyAssert.assertVocabulary;

import java.io.Reader;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.ReusableAnalyzerBase;

/**
 * Tests for {@link KStemmer}
 */
public class TestKStemmer extends BaseTokenStreamTestCase {
  Analyzer a = new ReusableAnalyzerBase() {
    @Override
    protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
      Tokenizer tokenizer = new MockTokenizer(reader, MockTokenizer.WHITESPACE, true);
      return new TokenStreamComponents(tokenizer, new KStemFilter(tokenizer));
    }
  };
 
  /** blast some random strings through the analyzer */
  public void testRandomStrings() throws Exception {
    checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
  }
  
  /** 
   * test the kstemmer optimizations against a bunch of words
   * that were stemmed with the original java kstemmer (generated from
   * testCreateMap, commented out below).
   */
  public void testVocabulary() throws Exception {
    assertVocabulary(a, getDataFile("kstemTestData.zip"), "kstem_examples.txt");
  }

  /****** requires original java kstem source code to create map
  public void testCreateMap() throws Exception {
    String input = getBigDoc();
    Reader r = new StringReader(input);
    TokenFilter tf = new LowerCaseFilter(new LetterTokenizer(r));
    // tf = new KStemFilter(tf);

    KStemmer kstem = new KStemmer();
    Map<String,String> map = new TreeMap();
    for(;;) {
      Token t = tf.next();
      if (t==null) break;
      String s = t.termText();
      if (map.containsKey(s)) continue;
      map.put(s, kstem.stem(s));
    }

    Writer out = new BufferedWriter(new FileWriter("kstem_examples.txt"));
    for (String key : map.keySet()) {
      out.write(key);
      out.write('\t');
      out.write(map.get(key));
      out.write('\n');
    }
    out.close();
  }
  ******/

}