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Lucene example source code file (EdgeNGramTokenFilterTest.java)

This example Lucene source code file (EdgeNGramTokenFilterTest.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

basetokenstreamtestcase, edgengramtokenfilter, edgengramtokenfilter, edgengramtokenfiltertest, exception, exception, illegalargumentexception, io, mocktokenizer, override, string, string, stringreader, stringreader, whitespacetokenizer

The Lucene EdgeNGramTokenFilterTest.java source code

package org.apache.lucene.analysis.ngram;

/**
 * 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.analysis.MockTokenizer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.WhitespaceTokenizer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;

import java.io.StringReader;

/**
 * Tests {@link EdgeNGramTokenFilter} for correctness.
 */
public class EdgeNGramTokenFilterTest extends BaseTokenStreamTestCase {
  private TokenStream input;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    input = new MockTokenizer(new StringReader("abcde"), MockTokenizer.WHITESPACE, false);
  }

  public void testInvalidInput() throws Exception {
    boolean gotException = false;
    try {        
      new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 0, 0);
    } catch (IllegalArgumentException e) {
      gotException = true;
    }
    assertTrue(gotException);
  }

  public void testInvalidInput2() throws Exception {
    boolean gotException = false;
    try {        
      new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 2, 1);
    } catch (IllegalArgumentException e) {
      gotException = true;
    }
    assertTrue(gotException);
  }

  public void testInvalidInput3() throws Exception {
    boolean gotException = false;
    try {        
      new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, -1, 2);
    } catch (IllegalArgumentException e) {
      gotException = true;
    }
    assertTrue(gotException);
  }

  public void testFrontUnigram() throws Exception {
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 1, 1);
    assertTokenStreamContents(tokenizer, new String[]{"a"}, new int[]{0}, new int[]{1});
  }

  public void testBackUnigram() throws Exception {
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.BACK, 1, 1);
    assertTokenStreamContents(tokenizer, new String[]{"e"}, new int[]{4}, new int[]{5});
  }

  public void testOversizedNgrams() throws Exception {
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 6, 6);
    assertTokenStreamContents(tokenizer, new String[0], new int[0], new int[0]);
  }

  public void testFrontRangeOfNgrams() throws Exception {
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 1, 3);
    assertTokenStreamContents(tokenizer, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{1,2,3});
  }

  public void testBackRangeOfNgrams() throws Exception {
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.BACK, 1, 3);
    assertTokenStreamContents(tokenizer, new String[]{"e","de","cde"}, new int[]{4,3,2}, new int[]{5,5,5});
  }
  
  public void testSmallTokenInStream() throws Exception {
    input = new MockTokenizer(new StringReader("abc de fgh"), MockTokenizer.WHITESPACE, false);
    EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, EdgeNGramTokenFilter.Side.FRONT, 3, 3);
    assertTokenStreamContents(tokenizer, new String[]{"abc","fgh"}, new int[]{0,7}, new int[]{3,10});
  }
  
  public void testReset() throws Exception {
    WhitespaceTokenizer tokenizer = new WhitespaceTokenizer(TEST_VERSION_CURRENT, new StringReader("abcde"));
    EdgeNGramTokenFilter filter = new EdgeNGramTokenFilter(tokenizer, EdgeNGramTokenFilter.Side.FRONT, 1, 3);
    assertTokenStreamContents(filter, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{1,2,3});
    tokenizer.reset(new StringReader("abcde"));
    assertTokenStreamContents(filter, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{1,2,3});
  }
}

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