FileDocCategorySizeDatePackage
PhraseScorer.javaAPI DocApache Lucene 1.4.34443Fri Oct 01 10:28:14 BST 2004org.apache.lucene.search

PhraseScorer

public abstract class PhraseScorer 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
protected byte[]
norms
protected float
value
private boolean
firstTime
private boolean
more
protected PhraseQueue
pq
protected PhrasePositions
first
protected PhrasePositions
last
private float
freq
Constructors Summary
PhraseScorer(Weight weight, TermPositions[] tps, int[] positions, Similarity similarity, byte[] norms)



         
                 
    super(similarity);
    this.norms = norms;
    this.weight = weight;
    this.value = weight.getValue();

    // convert tps to a list
    for (int i = 0; i < tps.length; i++) {
      PhrasePositions pp = new PhrasePositions(tps[i], positions[i]);
      if (last != null) {			  // add next to end of list
        last.next = pp;
      } else
        first = pp;
      last = pp;
    }

    pq = new PhraseQueue(tps.length);             // construct empty pq
Methods Summary
private booleandoNext()

    while (more) {
      while (more && first.doc < last.doc) {      // find doc w/ all the terms
        more = first.skipTo(last.doc);            // skip first upto last
        firstToLast();                            // and move it to the end
      }

      if (more) {
        // found a doc with all of the terms
        freq = phraseFreq();                      // check for phrase
        if (freq == 0.0f)                         // no match
          more = last.next();                     // trigger further scanning
        else
          return true;                            // found a match
      }
    }
    return false;                                 // no more matches
public intdoc()

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

    Explanation tfExplanation = new Explanation();

    while (next() && doc() < doc) {}

    float phraseFreq = (doc() == doc) ? freq : 0.0f;
    tfExplanation.setValue(getSimilarity().tf(phraseFreq));
    tfExplanation.setDescription("tf(phraseFreq=" + phraseFreq + ")");

    return tfExplanation;
protected final voidfirstToLast()

    last.next = first;			  // move first to end of list
    last = first;
    first = first.next;
    last.next = null;
private voidinit()

    for (PhrasePositions pp = first; more && pp != null; pp = pp.next) 
      more = pp.next();
    if(more)
      sort();
public booleannext()

    if (firstTime) {
      init();
      firstTime = false;
    } else if (more) {
      more = last.next();                         // trigger further scanning
    }
    return doNext();
protected abstract floatphraseFreq()

protected final voidpqToList()
    last = first = null;
    while (pq.top() != null) {
      PhrasePositions pp = (PhrasePositions) pq.pop();
      if (last != null) {			  // add next to end of list
        last.next = pp;
      } else
        first = pp;
      last = pp;
      pp.next = null;
    }
  
public floatscore()
    //System.out.println("scoring " + first.doc);
    float raw = getSimilarity().tf(freq) * value; // raw score
    return raw * Similarity.decodeNorm(norms[first.doc]); // normalize
  
public booleanskipTo(int target)
    for (PhrasePositions pp = first; more && pp != null; pp = pp.next) {
      more = pp.skipTo(target);
    }
    if (more)
      sort();                                     // re-sort
    return doNext();
  
private voidsort()
    pq.clear();
    for (PhrasePositions pp = first; pp != null; pp = pp.next)
      pq.put(pp);
    pqToList();
  
public java.lang.StringtoString()
 return "scorer(" + weight + ")";