Lucene example source code file (TestDutchStemmer.java)

This example Lucene source code file (TestDutchStemmer.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, chararrayset, deprecated, dutchanalyzer, dutchanalyzer, exception, exception, file, io, ioexception, ioexception, string, string, testdutchstemmer, zelf

The Lucene TestDutchStemmer.java source code

package org.apache.lucene.analysis.nl;

/**
 * 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 java.io.File;
import java.io.IOException;

import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.util.Version;

/**
 * Test the Dutch Stem Filter, which only modifies the term text.
 * 
 * The code states that it uses the snowball algorithm, but tests reveal some differences.
 * 
 */
public class TestDutchStemmer extends BaseTokenStreamTestCase {
  
  public void testWithSnowballExamples() throws Exception {
	 check("lichaamsziek", "lichaamsziek");
	 check("lichamelijk", "licham");
	 check("lichamelijke", "licham");
	 check("lichamelijkheden", "licham");
	 check("lichamen", "licham");
	 check("lichere", "licher");
	 check("licht", "licht");
	 check("lichtbeeld", "lichtbeeld");
	 check("lichtbruin", "lichtbruin");
	 check("lichtdoorlatende", "lichtdoorlat");
	 check("lichte", "licht");
	 check("lichten", "licht");
	 check("lichtende", "lichtend");
	 check("lichtenvoorde", "lichtenvoord");
	 check("lichter", "lichter");
	 check("lichtere", "lichter");
	 check("lichters", "lichter");
	 check("lichtgevoeligheid", "lichtgevoel");
	 check("lichtgewicht", "lichtgewicht");
	 check("lichtgrijs", "lichtgrijs");
	 check("lichthoeveelheid", "lichthoevel");
	 check("lichtintensiteit", "lichtintensiteit");
	 check("lichtje", "lichtj");
	 check("lichtjes", "lichtjes");
	 check("lichtkranten", "lichtkrant");
	 check("lichtkring", "lichtkring");
	 check("lichtkringen", "lichtkring");
	 check("lichtregelsystemen", "lichtregelsystem");
	 check("lichtste", "lichtst");
	 check("lichtstromende", "lichtstrom");
	 check("lichtte", "licht");
	 check("lichtten", "licht");
	 check("lichttoetreding", "lichttoetred");
	 check("lichtverontreinigde", "lichtverontreinigd");
	 check("lichtzinnige", "lichtzinn");
	 check("lid", "lid");
	 check("lidia", "lidia");
	 check("lidmaatschap", "lidmaatschap");
	 check("lidstaten", "lidstat");
	 check("lidvereniging", "lidveren");
	 check("opgingen", "opging");
	 check("opglanzing", "opglanz");
	 check("opglanzingen", "opglanz");
	 check("opglimlachten", "opglimlacht");
	 check("opglimpen", "opglimp");
	 check("opglimpende", "opglimp");
	 check("opglimping", "opglimp");
	 check("opglimpingen", "opglimp");
	 check("opgraven", "opgrav");
	 check("opgrijnzen", "opgrijnz");
	 check("opgrijzende", "opgrijz");
	 check("opgroeien", "opgroei");
	 check("opgroeiende", "opgroei");
	 check("opgroeiplaats", "opgroeiplat");
	 check("ophaal", "ophal");
	 check("ophaaldienst", "ophaaldienst");
	 check("ophaalkosten", "ophaalkost");
	 check("ophaalsystemen", "ophaalsystem");
	 check("ophaalt", "ophaalt");
	 check("ophaaltruck", "ophaaltruck");
	 check("ophalen", "ophal");
	 check("ophalend", "ophal");
	 check("ophalers", "ophaler");
	 check("ophef", "ophef");
	 check("opheldering", "ophelder");
	 check("ophemelde", "ophemeld");
	 check("ophemelen", "ophemel");
	 check("opheusden", "opheusd");
	 check("ophief", "ophief");
	 check("ophield", "ophield");
	 check("ophieven", "ophiev");
	 check("ophoepelt", "ophoepelt");
	 check("ophoog", "ophog");
	 check("ophoogzand", "ophoogzand");
	 check("ophopen", "ophop");
	 check("ophoping", "ophop");
	 check("ophouden", "ophoud");
  }
  
  /**
   * @deprecated remove this test in Lucene 4.0
   */
  @Deprecated
  public void testOldBuggyStemmer() throws Exception {
    Analyzer a = new DutchAnalyzer(Version.LUCENE_30);
    checkOneTermReuse(a, "opheffen", "ophef"); // versus snowball 'opheff'
    checkOneTermReuse(a, "opheffende", "ophef"); // versus snowball 'opheff'
    checkOneTermReuse(a, "opheffing", "ophef"); // versus snowball 'opheff'
  }
  
  public void testSnowballCorrectness() throws Exception {
    Analyzer a = new DutchAnalyzer(TEST_VERSION_CURRENT);
    checkOneTermReuse(a, "opheffen", "opheff");
    checkOneTermReuse(a, "opheffende", "opheff");
    checkOneTermReuse(a, "opheffing", "opheff");
  }
  
  public void testReusableTokenStream() throws Exception {
    Analyzer a = new DutchAnalyzer(TEST_VERSION_CURRENT); 
    checkOneTermReuse(a, "lichaamsziek", "lichaamsziek");
    checkOneTermReuse(a, "lichamelijk", "licham");
    checkOneTermReuse(a, "lichamelijke", "licham");
    checkOneTermReuse(a, "lichamelijkheden", "licham");
  }
  
  /* 
   * Test that changes to the exclusion table are applied immediately
   * when using reusable token streams.
   */
  public void testExclusionTableReuse() throws Exception {
    DutchAnalyzer a = new DutchAnalyzer(TEST_VERSION_CURRENT);
    checkOneTermReuse(a, "lichamelijk", "licham");
    a.setStemExclusionTable(new String[] { "lichamelijk" });
    checkOneTermReuse(a, "lichamelijk", "lichamelijk");

    
  }
  
  public void testExclusionTableViaCtor() throws IOException {
    CharArraySet set = new CharArraySet(Version.LUCENE_30, 1, true);
    set.add("lichamelijk");
    DutchAnalyzer a = new DutchAnalyzer(TEST_VERSION_CURRENT, CharArraySet.EMPTY_SET, set);
    assertAnalyzesToReuse(a, "lichamelijk lichamelijke", new String[] { "lichamelijk", "licham" });
    
    a = new DutchAnalyzer(TEST_VERSION_CURRENT, CharArraySet.EMPTY_SET, set);
    assertAnalyzesTo(a, "lichamelijk lichamelijke", new String[] { "lichamelijk", "licham" });

  }
  
  /* 
   * Test that changes to the dictionary stemming table are applied immediately
   * when using reusable token streams.
   */
  public void testStemDictionaryReuse() throws Exception {
    DutchAnalyzer a = new DutchAnalyzer(TEST_VERSION_CURRENT);
    checkOneTermReuse(a, "lichamelijk", "licham");
    File customDictFile = getDataFile("customStemDict.txt");
    a.setStemDictionary(customDictFile);
    checkOneTermReuse(a, "lichamelijk", "somethingentirelydifferent");
  }
  
  /**
   * Prior to 3.1, this analyzer had no lowercase filter.
   * stopwords were case sensitive. Preserve this for back compat.
   * @deprecated Remove this test in Lucene 4.0
   */
  @Deprecated
  public void testBuggyStopwordsCasing() throws IOException {
    DutchAnalyzer a = new DutchAnalyzer(Version.LUCENE_30);
    assertAnalyzesTo(a, "Zelf", new String[] { "zelf" });
  }
  
  /**
   * Test that stopwords are not case sensitive
   */
  public void testStopwordsCasing() throws IOException {
    DutchAnalyzer a = new DutchAnalyzer(Version.LUCENE_31);
    assertAnalyzesTo(a, "Zelf", new String[] { });
  }
  
  private void check(final String input, final String expected) throws Exception {
    checkOneTerm(new DutchAnalyzer(TEST_VERSION_CURRENT), input, expected); 
  }
  
  /** blast some random strings through the analyzer */
  public void testRandomStrings() throws Exception {
    checkRandomData(random, new DutchAnalyzer(TEST_VERSION_CURRENT), 10000*RANDOM_MULTIPLIER);
  }
  
}