beagled/Lucene.Net/Search/ExactPhraseScorer.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 using System;
  17 using Lucene.Net.Index;
  18 namespace Lucene.Net.Search
  19 {
  20
  21         sealed class ExactPhraseScorer:PhraseScorer
  22         {
  23
  24                 internal ExactPhraseScorer(Weight weight, TermPositions[] tps, int[] positions, Similarity similarity, byte[] norms) :
  25             base(weight, tps, positions, similarity, norms)
  26                 {
  27                 }
  28
  29                 protected internal override float PhraseFreq()
  30                 {
  31                         // sort list with pq
  32                         for (PhrasePositions pp = first; pp != null; pp = pp.next)
  33                         {
  34                                 pp.FirstPosition();
  35                                 pq.Put(pp); // build pq from list
  36                         }
  37                         PqToList(); // rebuild list from pq
  38
  39                         int freq = 0;
  40                         do
  41                         {
  42                                 // find position w/ all terms
  43                                 while (first.position < last.position)
  44                                 {
  45                                         // scan forward in first
  46                                         do
  47                                         {
  48                                                 if (!first.NextPosition())
  49                                                 {
  50                                                         return (float) freq;
  51                                                 }
  52                                         }
  53                                         while (first.position < last.position);
  54                                         FirstToLast();
  55                                 }
  56                                 freq++; // all equal: a match
  57                         }
  58                         while (last.NextPosition());
  59
  60                         return (float) freq;
  61                 }
  62         }
  63 }