FileDocCategorySizeDatePackage
TermScorer.javaAPI DocApache Lucene 1.4.33651Sun Jul 25 17:10:36 BST 2004org.apache.lucene.search

TermScorer

public final class TermScorer extends Scorer
Copyright 2004 The Apache Software Foundation Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Fields Summary
private Weight
weight
private TermDocs
termDocs
private byte[]
norms
private float
weightValue
private int
doc
private final int[]
docs
private final int[]
freqs
private int
pointer
private int
pointerMax
private static final int
SCORE_CACHE_SIZE
private float[]
scoreCache
Constructors Summary
TermScorer(Weight weight, TermDocs td, Similarity similarity, byte[] norms)


       
                 
    super(similarity);
    this.weight = weight;
    this.termDocs = td;
    this.norms = norms;
    this.weightValue = weight.getValue();

    for (int i = 0; i < SCORE_CACHE_SIZE; i++)
      scoreCache[i] = getSimilarity().tf(i) * weightValue;
Methods Summary
public intdoc()

 return doc;
public org.apache.lucene.search.Explanationexplain(int doc)

    TermQuery query = (TermQuery)weight.getQuery();
    Explanation tfExplanation = new Explanation();
    int tf = 0;
    while (pointer < pointerMax) {
      if (docs[pointer] == doc)
        tf = freqs[pointer];
      pointer++;
    }
    if (tf == 0) {
      while (termDocs.next()) {
        if (termDocs.doc() == doc) {
          tf = termDocs.freq();
        }
      }
    }
    termDocs.close();
    tfExplanation.setValue(getSimilarity().tf(tf));
    tfExplanation.setDescription("tf(termFreq("+query.getTerm()+")="+tf+")");
    
    return tfExplanation;
public booleannext()

    pointer++;
    if (pointer >= pointerMax) {
      pointerMax = termDocs.read(docs, freqs);    // refill buffer
      if (pointerMax != 0) {
        pointer = 0;
      } else {
        termDocs.close();			  // close stream
        doc = Integer.MAX_VALUE;		  // set to sentinel value
        return false;
      }
    } 
    doc = docs[pointer];
    return true;
public floatscore()

    int f = freqs[pointer];
    float raw =                                   // compute tf(f)*weight
      f < SCORE_CACHE_SIZE			  // check cache
      ? scoreCache[f]                             // cache hit
      : getSimilarity().tf(f)*weightValue;        // cache miss

    return raw * Similarity.decodeNorm(norms[doc]); // normalize for field
public booleanskipTo(int target)

    // first scan in cache
    for (pointer++; pointer < pointerMax; pointer++) {
      if (docs[pointer] >= target) {
        doc = docs[pointer];
        return true;
      }
    }

    // not found in cache, seek underlying stream
    boolean result = termDocs.skipTo(target);
    if (result) {
      pointerMax = 1;
      pointer = 0;
      docs[pointer] = doc = termDocs.doc();
      freqs[pointer] = termDocs.freq();
    } else {
      doc = Integer.MAX_VALUE;
    }
    return result;
public java.lang.StringtoString()

 return "scorer(" + weight + ")";