import org.apache.lucene.search.similarities.AfterEffectB; //导入依赖的package包/类
@Before
public void setupIndex() throws IOException {
    dirUnderTest = newDirectory();
    List<Similarity> sims = Arrays.asList(
            new ClassicSimilarity(),
            new SweetSpotSimilarity(), // extends Classic
            new BM25Similarity(),
            new LMDirichletSimilarity(),
            new BooleanSimilarity(),
            new LMJelinekMercerSimilarity(0.2F),
            new AxiomaticF3LOG(0.5F, 10),
            new DFISimilarity(new IndependenceChiSquared()),
            new DFRSimilarity(new BasicModelBE(), new AfterEffectB(), new NormalizationH1()),
            new IBSimilarity(new DistributionLL(), new LambdaDF(), new NormalizationH3())
        );
    similarity = sims.get(random().nextInt(sims.size()));

    indexWriterUnderTest = new RandomIndexWriter(random(), dirUnderTest, newIndexWriterConfig().setSimilarity(similarity));
    for (int i = 0; i < docs.length; i++) {
        Document doc = new Document();
        doc.add(newStringField("id", "" + i, Field.Store.YES));
        doc.add(newField("field", docs[i], Store.YES));
        indexWriterUnderTest.addDocument(doc);
    }
    indexWriterUnderTest.commit();
    indexWriterUnderTest.forceMerge(1);
    indexWriterUnderTest.flush();


    indexReaderUnderTest = indexWriterUnderTest.getReader();
    searcherUnderTest = newSearcher(indexReaderUnderTest);
    searcherUnderTest.setSimilarity(similarity);
}
 

import org.apache.lucene.search.similarities.AfterEffectB; //导入依赖的package包/类
private AfterEffect parseAfterEffect(String expr) {
  if ("B".equals(expr)) {
    return new AfterEffectB();
  } else if ("L".equals(expr)) {
    return new AfterEffectL();
  } else if ("none".equals(expr)) {
    return new AfterEffect.NoAfterEffect();
  } else {
    throw new RuntimeException("Invalid afterEffect: " + expr);
  }
}
 

import org.apache.lucene.search.similarities.AfterEffectB; //导入依赖的package包/类
/** dfr with default parameters */
public void test() throws Exception {
  Similarity sim = getSimilarity("text");
  assertEquals(DFRSimilarity.class, sim.getClass());
  DFRSimilarity dfr = (DFRSimilarity) sim;
  assertEquals(BasicModelIF.class, dfr.getBasicModel().getClass());
  assertEquals(AfterEffectB.class, dfr.getAfterEffect().getClass());
  assertEquals(NormalizationH2.class, dfr.getNormalization().getClass());
}
 

import org.apache.lucene.search.similarities.AfterEffectB; //导入依赖的package包/类
/** dfr with parameterized normalization */
public void testParameters() throws Exception {
  Similarity sim = getSimilarity("text_params");
  assertEquals(DFRSimilarity.class, sim.getClass());
  DFRSimilarity dfr = (DFRSimilarity) sim;
  assertEquals(BasicModelIF.class, dfr.getBasicModel().getClass());
  assertEquals(AfterEffectB.class, dfr.getAfterEffect().getClass());
  assertEquals(NormalizationH3.class, dfr.getNormalization().getClass());
  NormalizationH3 norm = (NormalizationH3) dfr.getNormalization();
  assertEquals(900f, norm.getMu(), 0.01f);
}