org.apache.lucene.search.Weight#explain ( )源码实例Demo

public Explanation explain(LeafReaderContext context, Weight childWeight) throws IOException {
  int prevParentDoc = parentBits.prevSetBit(parentApproximation.docID() - 1);
  int start = context.docBase + prevParentDoc + 1; // +1 b/c prevParentDoc is previous parent doc
  int end = context.docBase + parentApproximation.docID() - 1; // -1 b/c parentDoc is parent doc

  Explanation bestChild = null;
  int matches = 0;
  for (int childDoc = start; childDoc <= end; childDoc++) {
    Explanation child = childWeight.explain(context, childDoc - context.docBase);
    if (child.isMatch()) {
      matches++;
      if (bestChild == null || child.getValue().floatValue() > bestChild.getValue().floatValue()) {
        bestChild = child;
      }
    }
  }

  return Explanation.match(score(), String.format(Locale.ROOT,
      "Score based on %d child docs in range from %d to %d, best match:", matches, start, end), bestChild
  );
}
 

@Override
public Explanation explain(IndexSearcher searcher,
    Explanation firstPassExplanation, int docID) throws IOException {

  final List<LeafReaderContext> leafContexts = searcher.getTopReaderContext()
      .leaves();
  final int n = ReaderUtil.subIndex(docID, leafContexts);
  final LeafReaderContext context = leafContexts.get(n);
  final int deBasedDoc = docID - context.docBase;
  final Weight modelWeight = searcher.createWeight(searcher.rewrite(scoringQuery),
      ScoreMode.COMPLETE, 1);
  return modelWeight.explain(context, deBasedDoc);
}
 

@Test
public void testThatQueryUsesTermButNoFieldBoost() throws Exception {

    Analyzer analyzer = new StandardAnalyzer();

    Directory directory = new ByteBuffersDirectory();
    IndexWriterConfig config = new IndexWriterConfig(analyzer);
    config.setSimilarity(new ClassicSimilarity());
    IndexWriter indexWriter = new IndexWriter(directory, config);


    TestUtil.addNumDocsWithTextField("f1", "v1 v1", indexWriter, 4);
    TestUtil.addNumDocsWithTextField("f1", "v2", indexWriter, 1);

    indexWriter.close();

    IndexReader indexReader = DirectoryReader.open(directory);
    IndexSearcher indexSearcher = new IndexSearcher(indexReader);
    indexSearcher.setSimilarity(new ClassicSimilarity());


    final TermQuery termQuery = new LuceneTermQueryBuilder()
            .createTermQuery(new Term("f1", "v1"), new ConstantFieldBoost(3f));
    final Term term = termQuery.getTerm();
    assertEquals("f1", term.field());
    assertEquals("v1", term.text());

    TopDocs topDocs = indexSearcher.search(termQuery, 10);

    final Weight weight = termQuery.createWeight(indexSearcher, ScoreMode.COMPLETE, 4.5f);
    final Explanation explain = weight.explain(indexReader.getContext().leaves().get(0), topDocs.scoreDocs[0].doc);

    String explainText = explain.toString();

    assertTrue(explainText.contains("4.5 = boost")); // 4.5 (query) but ignore field boost
    assertTrue(explainText.contains("4 = docFreq")); // 4 * v1
    assertTrue(explainText.contains("2.0 = freq")); // 2 * v1 in field
}
 

@Test
public void testCreateWeight() throws Exception {

    Analyzer analyzer = new StandardAnalyzer();

    Directory directory = new ByteBuffersDirectory();
    IndexWriterConfig config = new IndexWriterConfig(analyzer);
    config.setSimilarity(new ClassicSimilarity());
    IndexWriter indexWriter = new IndexWriter(directory, config);

    TestUtil.addNumDocsWithTextField("f1", "v1", indexWriter, 4);
    TestUtil.addNumDocsWithTextField("f2", "v1 v1", indexWriter, 1);

    indexWriter.close();

    IndexReader indexReader = DirectoryReader.open(directory);
    IndexSearcher indexSearcher = new IndexSearcher(indexReader);
    indexSearcher.setSimilarity(new ClassicSimilarity());


    DocumentFrequencyCorrection dfc = new DocumentFrequencyCorrection();

    Term qTerm1 = new Term("f1", "v1");
    Term qTerm2 = new Term("f2", "v1");
    dfc.newClause();
    dfc.prepareTerm(qTerm1);
    dfc.prepareTerm(qTerm2);
    dfc.finishedUserQuery();

    DependentTermQueryBuilder.DependentTermQuery query1 = new DependentTermQueryBuilder(dfc)
            .createTermQuery(qTerm1, fieldBoost1);
    DependentTermQueryBuilder.DependentTermQuery query2 = new DependentTermQueryBuilder(dfc)
            .createTermQuery(qTerm2, fieldBoost2);


    TopDocs topDocs = indexSearcher.search(query2, 10);

    final Weight weight2 = query2.createWeight(indexSearcher, ScoreMode.COMPLETE, 4.5f);
    final Explanation explain = weight2.explain(indexReader.leaves().get(0), topDocs.scoreDocs[0].doc);

    String explainText = explain.toString();
    assertTrue(explainText.contains("9.0 = boost")); // 4.5 (query) * 2.0 (field)
    assertTrue(explainText.contains("4 = docFreq")); // 4 * df of f1:v1
    assertTrue(explainText.contains("2.0 = freq")); // don't use tf

    indexReader.close();
    directory.close();
    analyzer.close();

}
 

@Test
public void testCreateWeight() throws Exception {

    Analyzer analyzer = new KeywordAnalyzer();

    Directory directory = newDirectory();
    RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory, analyzer);

    TestUtil.addNumDocsWithStringField("f1", "v1", indexWriter, 4);
    TestUtil.addNumDocsWithStringField("f1", "v2", indexWriter, 1);

    indexWriter.close();

    IndexReader indexReader = DirectoryReader.open(directory);
    IndexSearcher indexSearcher = newSearcher(indexReader);
    indexSearcher.setSimilarity(new ClassicSimilarity());


    Term term = new Term("f1", "v1");

    FieldBoostTermQueryBuilder.FieldBoostTermQuery query = new FieldBoostTermQueryBuilder().createTermQuery(term, fieldBoost2);

    TopDocs topDocs = indexSearcher.search(query, 10);
    final Weight weight = query.createWeight(indexSearcher, ScoreMode.COMPLETE, 4.5f);
    final Explanation explain = weight.explain(indexReader.getContext().leaves().get(0), topDocs.scoreDocs[0].doc);

    String explainText = explain.toString();

    assertTrue(explainText.contains("4.5 = queryBoost")); // 4.5 (query)
    assertTrue(explainText.contains("2.0 = fieldBoost")); // 2.0 (field)
    assertTrue(explainText.contains("ConstantFieldBoost(f1^2.0)")); // 2.0 (field)
    assertFalse(explainText.toLowerCase().contains("freq")); // no doc freq

    indexReader.close();
    directory.close();
    analyzer.close();

}
 

@Test
public void testCreateWeight() throws Exception {

    Analyzer analyzer = new StandardAnalyzer();

    Directory directory = new ByteBuffersDirectory();
    IndexWriterConfig config = new IndexWriterConfig(analyzer);
    config.setSimilarity(new ClassicSimilarity());
    IndexWriter indexWriter = new IndexWriter(directory, config);


    TestUtil.addNumDocsWithTextField("f1", "v1 v1", indexWriter, 4);
    TestUtil.addNumDocsWithTextField("f1", "v2", indexWriter, 1);

    indexWriter.close();

    IndexReader indexReader = DirectoryReader.open(directory);
    IndexSearcher indexSearcher = new IndexSearcher(indexReader);
    indexSearcher.setSimilarity(new ClassicSimilarity());


    Term term = new Term("f1", "v1");

    SimilarityTermQuery query = new SimilarityTermQueryBuilder().createTermQuery(term, fieldBoost2);

    TopDocs topDocs = indexSearcher.search(query, 10);

    final Weight weight = query.createWeight(indexSearcher, ScoreMode.COMPLETE, 4.5f);
    final Explanation explain = weight.explain(indexReader.getContext().leaves().get(0), topDocs.scoreDocs[0].doc);

    String explainText = explain.toString();

    assertTrue(explainText.contains("9.0 = boost")); // 4.5 (query) * 2.0 (field)
    assertTrue(explainText.contains("4 = docFreq")); // 4 * v1
    assertTrue(explainText.contains("2.0 = freq")); // 2 * v1 in field

    indexReader.close();
    directory.close();
    analyzer.close();

}