Lucene example source code file (FSTLookupTest.java)

This example Lucene source code file (FSTLookupTest.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

arraylist, exception, exception, expected, fstlookup, fstlookup, list, result, string, string, stringbuilder, termfreq, termfreq, termfreqarrayiterator, util

The Lucene FSTLookupTest.java source code

package org.apache.lucene.search.suggest.fst;

/**
 * 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.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.Random;

import org.apache.lucene.search.suggest.Lookup.LookupResult;
import org.apache.lucene.search.suggest.fst.FSTLookup;
import org.apache.lucene.util.LuceneTestCase;

import org.apache.lucene.search.suggest.LookupBenchmarkTest;
import org.apache.lucene.search.suggest.TermFreq;
import org.apache.lucene.search.suggest.TermFreqArrayIterator;

/**
 * Unit tests for {@link FSTLookup}.
 */
public class FSTLookupTest extends LuceneTestCase {
  public static TermFreq tf(String t, float v) {
    return new TermFreq(t, v);
  }

  private FSTLookup lookup;

  public void setUp() throws Exception {
    super.setUp();
    final TermFreq[] keys = new TermFreq[] {
        tf("one", 0.5f),
        tf("oneness", 1),
        tf("onerous", 1),
        tf("onesimus", 1),
        tf("two", 1),
        tf("twofold", 1),
        tf("twonk", 1),
        tf("thrive", 1),
        tf("through", 1),
        tf("threat", 1),
        tf("three", 1),
        tf("foundation", 1),
        tf("fourier", 1),
        tf("four", 1),
        tf("fourty", 1),
        tf("xo", 1),
      };

      lookup = new FSTLookup();
      lookup.build(new TermFreqArrayIterator(keys));
  }

  public void testExactMatchHighPriority() throws Exception {
    assertMatchEquals(lookup.lookup("two", true, 1), "two/1.0");
  }

  public void testExactMatchLowPriority() throws Exception {
    assertMatchEquals(lookup.lookup("one", true, 2), 
        "one/0.0",
        "oneness/1.0");
  }

  public void testMiss() throws Exception {
    assertMatchEquals(lookup.lookup("xyz", true, 1));
  }

  public void testAlphabeticWithWeights() throws Exception {
    assertEquals(0, lookup.lookup("xyz", false, 1).size());
  }

  public void testFullMatchList() throws Exception {
    assertMatchEquals(lookup.lookup("one", true, Integer.MAX_VALUE),
        "oneness/1.0", 
        "onerous/1.0",
        "onesimus/1.0", 
        "one/0.0");
  }

  public void testMultilingualInput() throws Exception {
    List<TermFreq> input = LookupBenchmarkTest.readTop50KWiki();

    lookup = new FSTLookup();
    lookup.build(new TermFreqArrayIterator(input));

    for (TermFreq tf : input) {
      assertTrue("Not found: " + tf.term, lookup.get(tf.term) != null);
      assertEquals(tf.term, lookup.lookup(tf.term, true, 1).get(0).key);
    }
  }

  public void testEmptyInput() throws Exception {
    lookup = new FSTLookup();
    lookup.build(new TermFreqArrayIterator(new TermFreq[0]));
    
    assertMatchEquals(lookup.lookup("", true, 10));
  }

  public void testRandom() throws Exception {
    List<TermFreq> freqs = new ArrayList();
    Random rnd = random;
    for (int i = 0; i < 5000; i++) {
      freqs.add(new TermFreq("" + rnd.nextLong(), rnd.nextInt(100)));
    }
    lookup = new FSTLookup();
    lookup.build(new TermFreqArrayIterator(freqs.toArray(new TermFreq[freqs.size()])));

    for (TermFreq tf : freqs) {
      final String term = tf.term;
      for (int i = 1; i < term.length(); i++) {
        String prefix = term.substring(0, i);
        for (LookupResult lr : lookup.lookup(prefix, true, 10)) {
          assertTrue(lr.key.startsWith(prefix));
        }
      }
    }
  }

  private void assertMatchEquals(List<LookupResult> res, String... expected) {
    String [] result = new String [res.size()];
    for (int i = 0; i < res.size(); i++)
      result[i] = res.get(i).toString();
    
    if (!Arrays.equals(expected, result)) {
      int colLen = Math.max(maxLen(expected), maxLen(result));
      
      StringBuilder b = new StringBuilder();
      String format = "%" + colLen + "s  " + "%" + colLen + "s\n"; 
      b.append(String.format(Locale.ENGLISH, format, "Expected", "Result"));
      for (int i = 0; i < Math.max(result.length, expected.length); i++) {
        b.append(String.format(Locale.ENGLISH, format, 
            i < expected.length ? expected[i] : "--", 
            i < result.length ? result[i] : "--"));
      }

      System.err.println(b.toString());
      fail("Expected different output:\n" + b.toString());
    }
  }

  private int maxLen(String[] result) {
    int len = 0;
    for (String s : result)
      len = Math.max(len, s.length());
    return len;
  }
}