1   package org.apache.lucene.search;
2   
3   /**
4    * Licensed to the Apache Software Foundation (ASF) under one or more
5    * contributor license agreements.  See the NOTICE file distributed with
6    * this work for additional information regarding copyright ownership.
7    * The ASF licenses this file to You under the Apache License, Version 2.0
8    * (the "License"); you may not use this file except in compliance with
9    * the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  
20  import java.io.IOException;
21  import org.apache.lucene.index.*;
22  
23  final class ExactPhraseScorer extends PhraseScorer {
24  
25    ExactPhraseScorer(Weight weight, TermPositions[] tps, int[] offsets, Similarity similarity,
26                      byte[] norms) {
27      super(weight, tps, offsets, similarity, norms);
28    }
29  
30    protected final float phraseFreq() throws IOException {
31      // sort list with pq
32      pq.clear();
33      for (PhrasePositions pp = first; pp != null; pp = pp.next) {
34        pp.firstPosition();
35        pq.put(pp);                 // build pq from list
36      }
37      pqToList();                   // rebuild list from pq
38  
39      // for counting how many times the exact phrase is found in current document,
40      // just count how many times all PhrasePosition's have exactly the same position.   
41      int freq = 0;
42      do {                      // find position w/ all terms
43        while (first.position < last.position) {    // scan forward in first
44          do {
45            if (!first.nextPosition())
46              return (float)freq;
47          } while (first.position < last.position);
48            firstToLast();
49        }
50        freq++;                     // all equal: a match
51      } while (last.nextPosition());
52    
53      return (float)freq;
54    }
55  }
56