org.apache.lucene.index.IndexReader#norms ( )源码实例Demo

final Scorer scorer(IndexReader reader) throws IOException {
   if (terms.size() == 0)			  // optimize zero-term case
     return null;
   if (terms.size() == 1) {			  // optimize one-term case
     Term term = (Term)terms.elementAt(0);
     TermDocs docs = reader.termDocs(term);
     if (docs == null)
return null;
     return new TermScorer(docs, reader.norms(term.field()), weight);
   }

   TermPositions[] tps = new TermPositions[terms.size()];
   for (int i = 0; i < terms.size(); i++) {
     TermPositions p = reader.termPositions((Term)terms.elementAt(i));
     if (p == null)
return null;
     tps[i] = p;
   }

   if (slop == 0)				  // optimize exact case
     return new ExactPhraseScorer(tps, reader.norms(field), weight);
   else
     return
new SloppyPhraseScorer(tps, slop, reader.norms(field), weight);

 }
 

final Scorer scorer(IndexReader reader) throws IOException {
   if (terms.size() == 0)			  // optimize zero-term case
     return null;
   if (terms.size() == 1) {			  // optimize one-term case
     Term term = (Term)terms.elementAt(0);
     TermDocs docs = reader.termDocs(term);
     if (docs == null)
return null;
     return new TermScorer(docs, reader.norms(term.field()), weight);
   }

   TermPositions[] tps = new TermPositions[terms.size()];
   for (int i = 0; i < terms.size(); i++) {
     TermPositions p = reader.termPositions((Term)terms.elementAt(i));
     if (p == null)
return null;
     tps[i] = p;
   }

   if (slop == 0)				  // optimize exact case
     return new ExactPhraseScorer(tps, reader.norms(field), weight);
   else
     return
new SloppyPhraseScorer(tps, slop, reader.norms(field), weight);

 }
 

public Scorer scorer(IndexReader reader) throws IOException {
  TermDocs termDocs = reader.termDocs(term);

  if (termDocs == null)
    return null;

  String field = term.field();
  return new TermScorer(this, termDocs, similarity,
          reader.hasNorms(field) ? reader.norms(field) : null);
}
 

public Explanation explain(IndexReader reader, int doc)
  throws IOException {

  ComplexExplanation result = new ComplexExplanation();
  result.setDescription("weight("+getQuery()+" in "+doc+"), product of:");

  Explanation idfExpl =
    new Explanation(idf, "idf(docFreq=" + reader.docFreq(term) +
        ", numDocs=" + reader.numDocs() + ")");

  // explain query weight
  Explanation queryExpl = new Explanation();
  queryExpl.setDescription("queryWeight(" + getQuery() + "), product of:");

  Explanation boostExpl = new Explanation(getBoost(), "boost");
  if (getBoost() != 1.0f)
    queryExpl.addDetail(boostExpl);
  queryExpl.addDetail(idfExpl);

  Explanation queryNormExpl = new Explanation(queryNorm,"queryNorm");
  queryExpl.addDetail(queryNormExpl);

  queryExpl.setValue(boostExpl.getValue() *
                     idfExpl.getValue() *
                     queryNormExpl.getValue());

  result.addDetail(queryExpl);

  // explain field weight
  String field = term.field();
  ComplexExplanation fieldExpl = new ComplexExplanation();
  fieldExpl.setDescription("fieldWeight("+term+" in "+doc+
                           "), product of:");

  Explanation tfExpl = scorer(reader).explain(doc);
  fieldExpl.addDetail(tfExpl);
  fieldExpl.addDetail(idfExpl);

  Explanation fieldNormExpl = new Explanation();
  byte[] fieldNorms = reader.norms(field);
  float fieldNorm =
    fieldNorms!=null ? Similarity.decodeNorm(fieldNorms[doc]) : 0.0f;
  fieldNormExpl.setValue(fieldNorm);
  fieldNormExpl.setDescription("fieldNorm(field="+field+", doc="+doc+")");
  fieldExpl.addDetail(fieldNormExpl);
  
  fieldExpl.setMatch(Boolean.valueOf(tfExpl.isMatch()));
  fieldExpl.setValue(tfExpl.getValue() *
                     idfExpl.getValue() *
                     fieldNormExpl.getValue());

  result.addDetail(fieldExpl);
  result.setMatch(fieldExpl.getMatch());
  
  // combine them
  result.setValue(queryExpl.getValue() * fieldExpl.getValue());

  if (queryExpl.getValue() == 1.0f)
    return fieldExpl;

  return result;
}