code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2014 Daniel Naber (http://www.danielnaber.de)
   * 
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
   * USA
   */
  package org.languagetool.languagemodel;
  
  import org.junit.Ignore;
  import org.junit.Test;
  import org.languagetool.JLanguageTool;
  
  import java.io.File;
  import java.net.URL;
  import java.util.Arrays;
  
  import static org.hamcrest.CoreMatchers.is;
  import static org.hamcrest.MatcherAssert.assertThat;
  
  public class LuceneSingleIndexLanguageModelTest extends LanguageModelTest {
  
    @Test
    public void testLanguageModel() throws Exception {
      URL ngramUrl = JLanguageTool.getDataBroker().getFromResourceDirAsUrl("/yy/ngram-index");
      try (LuceneLanguageModel model = new LuceneLanguageModel(new File(ngramUrl.toURI()))) {
        assertThat(model.getCount("the"), is(55L));
        assertThat(model.getCount(Arrays.asList("the", "nice")), is(3L));
        assertThat(model.getCount(Arrays.asList("the", "nice", "building")), is(1L));
        assertThat(model.getCount("not-in-here"), is(0L));
        assertThat(model.getTotalTokenCount(), is(3L));
      }
    }
  
    /**
     * Some values for average time per lookup on 2grams on a 3.7GB Lucene 4.8.1 index with 118,941,740 docs:
     * -no data in OS cache, index on external USB disk: 17626µs = 17ms
     * -no data in OS cache, index on SSD: 739µs = <0ms
     * -all data in OS cache (by running the test more than once): 163µs = <0ms
     * 
     * Some values for average time per lookup on 3grams on a 7.0GB Lucene 4.9 index:
     * -no data in OS cache, index on external USB disk: 13256µs = 13ms
     * -no data in OS cache, index on SSD: 791µs = <0ms
     * -all(?) data in OS cache (by running the test more than once): 162µs = <0ms
     * 
     * The tests have been performed on a Dell XSP13 (i7-3537U CPU) under Ubuntu 12.04, with Java 1.7.
     */
    @Test
    @Ignore("for interactive use only")
    public void testPerformance() throws Exception {
      // 2grams:
      //LanguageModel model = new LuceneLanguageModel(new File("/media/Data/google-ngram/2gram/lucene-index/merged/"));
      //super.testPerformance(model, 2);
      // 3grams:
      //LanguageModel model = new LuceneLanguageModel(new File("/media/Data/google-ngram/3gram/aggregated/lucene-index/merged/"));
      LuceneLanguageModel model = new LuceneLanguageModel(new File("/data/google-gram-index/"));
      super.testPerformance(model, 3);
    }
    
  }
  