lucene/analysis/common/src/test/org/apache/lucene/analysis/en/TestKStemmer.java

/*
 * 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.
 */
package org.apache.lucene.analysis.en;

import static org.apache.lucene.analysis.VocabularyAssert.assertVocabulary;

import java.io.IOException;
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.core.KeywordTokenizer;
import org.junit.Ignore;

/** Tests for {@link KStemmer} */
public class TestKStemmer extends BaseTokenStreamTestCase {
  private Analyzer a;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    a =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Tokenizer tokenizer = new MockTokenizer(MockTokenizer.WHITESPACE, true);
            return new TokenStreamComponents(tokenizer, new KStemFilter(tokenizer));
          }
        };
  }

  @Override
  public void tearDown() throws Exception {
    a.close();
    super.tearDown();
  }

  /** blast some random strings through the analyzer */
  public void testRandomStrings() throws Exception {
    checkRandomData(random(), a, 200 * 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, getDataPath("kstemTestData.zip"), "kstem_examples.txt");
  }

  public void testEmptyTerm() throws IOException {
    Analyzer a =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Tokenizer tokenizer = new KeywordTokenizer();
            return new TokenStreamComponents(tokenizer, new KStemFilter(tokenizer));
          }
        };
    checkOneTerm(a, "", "");
    a.close();
  }

  /**
   * Requires original java kstem source code to create map.
   *
   * <pre>{@code
   * 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();
   * }</pre>
   */
  @Ignore("Sample map creation code.")
  public void testCreateMap() {}
}