Lucene.Net  3.0.3
Lucene.Net is a port of the Lucene search engine library, written in C# and targeted at .NET runtime users.
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Properties Pages
ReqOptSumScorer.cs
Go to the documentation of this file.
1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 using System;
19 
20 namespace Lucene.Net.Search
21 {
22 
23  /// <summary>A Scorer for queries with a required part and an optional part.
24  /// Delays skipTo() on the optional part until a score() is needed.
25  /// <br/>
26  /// This <c>Scorer</c> implements <see cref="DocIdSetIterator.Advance(int)" />.
27  /// </summary>
29  {
30  /// <summary>The scorers passed from the constructor.
31  /// These are set to null as soon as their next() or skipTo() returns false.
32  /// </summary>
33  private Scorer reqScorer;
34  private Scorer optScorer;
35 
36  /// <summary>Construct a <c>ReqOptScorer</c>.</summary>
37  /// <param name="reqScorer">The required scorer. This must match.
38  /// </param>
39  /// <param name="optScorer">The optional scorer. This is used for scoring only.
40  /// </param>
41  public ReqOptSumScorer(Scorer reqScorer, Scorer optScorer):base(null)
42  { // No similarity used.
43  this.reqScorer = reqScorer;
44  this.optScorer = optScorer;
45  }
46 
47  public override int NextDoc()
48  {
49  return reqScorer.NextDoc();
50  }
51 
52  public override int Advance(int target)
53  {
54  return reqScorer.Advance(target);
55  }
56 
57  public override int DocID()
58  {
59  return reqScorer.DocID();
60  }
61 
62  /// <summary>Returns the score of the current document matching the query.
63  /// Initially invalid, until <see cref="NextDoc()" /> is called the first time.
64  /// </summary>
65  /// <returns> The score of the required scorer, eventually increased by the score
66  /// of the optional scorer when it also matches the current document.
67  /// </returns>
68  public override float Score()
69  {
70  int curDoc = reqScorer.DocID();
71  float reqScore = reqScorer.Score();
72  if (optScorer == null)
73  {
74  return reqScore;
75  }
76 
77  int optScorerDoc = optScorer.DocID();
78  if (optScorerDoc < curDoc && (optScorerDoc = optScorer.Advance(curDoc)) == NO_MORE_DOCS)
79  {
80  optScorer = null;
81  return reqScore;
82  }
83 
84  return optScorerDoc == curDoc?reqScore + optScorer.Score():reqScore;
85  }
86  }
87 }