import org.apache.lucene.search.similarities.BasicModelBE; //导入依赖的package包/类
private BasicModel parseBasicModel(String expr) {
  if ("Be".equals(expr)) {
    return new BasicModelBE();
  } else if ("D".equals(expr)) {
    return new BasicModelD();
  } else if ("G".equals(expr)) {
    return new BasicModelG();
  } else if ("I(F)".equals(expr)) {
    return new BasicModelIF();
  } else if ("I(n)".equals(expr)) {
    return new BasicModelIn();
  } else if ("I(ne)".equals(expr)) {
    return new BasicModelIne();
  } else if ("P".equals(expr)) {
    return new BasicModelP();
  } else {
    throw new RuntimeException("Invalid basicModel: " + expr);
  }
}
 

import org.apache.lucene.search.similarities.BasicModelBE; //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);
}