teststopanalyzer.java

Lucene a java open-source SearchEngine Framework

package org.apache.lucene.analysis;

/**
 * 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.util.LuceneTestCase;

import java.io.StringReader;
import java.io.IOException;
import java.util.Set;
import java.util.HashSet;

public class TestStopAnalyzer extends LuceneTestCase {
  
  private StopAnalyzer stop = new StopAnalyzer();
  private Set inValidTokens = new HashSet();
  
  public TestStopAnalyzer(String s) {
    super(s);
  }

  protected void setUp() throws Exception {
    super.setUp();
    for (int i = 0; i < StopAnalyzer.ENGLISH_STOP_WORDS.length; i++) {
      inValidTokens.add(StopAnalyzer.ENGLISH_STOP_WORDS[i]);
    }
  }

  public void testDefaults() throws IOException {
    assertTrue(stop != null);
    StringReader reader = new StringReader("This is a test of the english stop analyzer");
    TokenStream stream = stop.tokenStream("test", reader);
    assertTrue(stream != null);
    Token token = null;
    while ((token = stream.next()) != null) {
      assertFalse(inValidTokens.contains(token.termText()));
    }
  }

  public void testStopList() throws IOException {
    Set stopWordsSet = new HashSet();
    stopWordsSet.add("good");
    stopWordsSet.add("test");
    stopWordsSet.add("analyzer");
    StopAnalyzer newStop = new StopAnalyzer((String[])stopWordsSet.toArray(new String[3]));
    StringReader reader = new StringReader("This is a good test of the english stop analyzer");
    TokenStream stream = newStop.tokenStream("test", reader);
    assertNotNull(stream);
    Token token = null;
    while ((token = stream.next()) != null) {
      String text = token.termText();
      assertFalse(stopWordsSet.contains(text));
      assertEquals(1,token.getPositionIncrement()); // by default stop tokenizer does not apply increments.
    }
  }

  public void testStopListPositions() throws IOException {
    boolean defaultEnable = StopFilter.getEnablePositionIncrementsDefault();
    StopFilter.setEnablePositionIncrementsDefault(true);
    try {
      Set stopWordsSet = new HashSet();
      stopWordsSet.add("good");
      stopWordsSet.add("test");
      stopWordsSet.add("analyzer");
      StopAnalyzer newStop = new StopAnalyzer((String[])stopWordsSet.toArray(new String[3]));
      StringReader reader = new StringReader("This is a good test of the english stop analyzer with positions");
      int expectedIncr[] =                  { 1,   1, 1,          3, 1,  1,      1,            2,   1};
      TokenStream stream = newStop.tokenStream("test", reader);
      assertNotNull(stream);
      Token token = null;
      int i = 0;
      while ((token = stream.next()) != null) {
        String text = token.termText();
        assertFalse(stopWordsSet.contains(text));
        assertEquals(expectedIncr[i++],token.getPositionIncrement());
      }
    } finally {
      StopFilter.setEnablePositionIncrementsDefault(defaultEnable);
    }
  }

}