Lucene example source code file (TestGermanAnalyzer.java)

This example Lucene source code file (TestGermanAnalyzer.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

chararrayset, chararrayset, exception, fischen, germananalyzer, germananalyzer, germanstemfilter, germanstemfilter, io, ioexception, lowercasetokenizer, string, string, stringreader, trinken

The Lucene TestGermanAnalyzer.java source code

package org.apache.lucene.analysis.de;

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

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

public class TestGermanAnalyzer extends BaseTokenStreamTestCase {
  public void testReusableTokenStream() throws Exception {
    Analyzer a = new GermanAnalyzer(TEST_VERSION_CURRENT);
    checkOneTermReuse(a, "Tisch", "tisch");
    checkOneTermReuse(a, "Tische", "tisch");
    checkOneTermReuse(a, "Tischen", "tisch");
  }
  
  public void testExclusionTableBWCompat() throws IOException {
    GermanStemFilter filter = new GermanStemFilter(new LowerCaseTokenizer(TEST_VERSION_CURRENT, 
        new StringReader("Fischen Trinken")));
    CharArraySet set = new CharArraySet(TEST_VERSION_CURRENT, 1, true);
    set.add("fischen");
    filter.setExclusionSet(set);
    assertTokenStreamContents(filter, new String[] { "fischen", "trink" });
  }

  public void testWithKeywordAttribute() throws IOException {
    CharArraySet set = new CharArraySet(TEST_VERSION_CURRENT, 1, true);
    set.add("fischen");
    GermanStemFilter filter = new GermanStemFilter(
        new KeywordMarkerFilter(new LowerCaseTokenizer(TEST_VERSION_CURRENT, new StringReader( 
            "Fischen Trinken")), set));
    assertTokenStreamContents(filter, new String[] { "fischen", "trink" });
  }

  public void testWithKeywordAttributeAndExclusionTable() throws IOException {
    CharArraySet set = new CharArraySet(TEST_VERSION_CURRENT, 1, true);
    set.add("fischen");
    CharArraySet set1 = new CharArraySet(TEST_VERSION_CURRENT, 1, true);
    set1.add("trinken");
    set1.add("fischen");
    GermanStemFilter filter = new GermanStemFilter(
        new KeywordMarkerFilter(new LowerCaseTokenizer(TEST_VERSION_CURRENT, new StringReader(
            "Fischen Trinken")), set));
    filter.setExclusionSet(set1);
    assertTokenStreamContents(filter, new String[] { "fischen", "trinken" });
  }
  
  /* 
   * Test that changes to the exclusion table are applied immediately
   * when using reusable token streams.
   */
  public void testExclusionTableReuse() throws Exception {
    GermanAnalyzer a = new GermanAnalyzer(TEST_VERSION_CURRENT);
    checkOneTermReuse(a, "tischen", "tisch");
    a.setStemExclusionTable(new String[] { "tischen" });
    checkOneTermReuse(a, "tischen", "tischen");
  }
  
  /** test some features of the new snowball filter
   * these only pass with LUCENE_CURRENT, not if you use o.a.l.a.de.GermanStemmer
   */
  public void testGermanSpecials() throws Exception {
    GermanAnalyzer a = new GermanAnalyzer(TEST_VERSION_CURRENT);
    // a/o/u + e is equivalent to the umlaut form
    checkOneTermReuse(a, "Schaltflächen", "schaltflach");
    checkOneTermReuse(a, "Schaltflaechen", "schaltflach");
    // here they are with the old stemmer
    a = new GermanAnalyzer(Version.LUCENE_30);
    checkOneTermReuse(a, "Schaltflächen", "schaltflach");
    checkOneTermReuse(a, "Schaltflaechen", "schaltflaech");
  }
  
  /** blast some random strings through the analyzer */
  public void testRandomStrings() throws Exception {
    checkRandomData(random, new GermanAnalyzer(TEST_VERSION_CURRENT), 10000*RANDOM_MULTIPLIER);
  }
}