mcs/tools/monkeydoc/Lucene.Net/Lucene.Net/Search/Spans/SpanWeight.cs

   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 using IndexReader = Mono.Lucene.Net.Index.IndexReader;
  21 using Mono.Lucene.Net.Search;
  22 using IDFExplanation = Mono.Lucene.Net.Search.Explanation.IDFExplanation;
  23
  24 namespace Mono.Lucene.Net.Search.Spans
  25 {
  26
  27         /// <summary> Expert-only.  Public for use by other weight implementations</summary>
  28         [Serializable]
  29         public class SpanWeight:Weight
  30         {
  31                 protected internal Similarity similarity;
  32                 protected internal float value_Renamed;
  33                 protected internal float idf;
  34                 protected internal float queryNorm;
  35                 protected internal float queryWeight;
  36
  37                 protected internal System.Collections.Hashtable terms;
  38                 protected internal SpanQuery query;
  39                 private IDFExplanation idfExp;
  40
  41                 public SpanWeight(SpanQuery query, Searcher searcher)
  42                 {
  43                         this.similarity = query.GetSimilarity(searcher);
  44                         this.query = query;
  45                         terms = new System.Collections.Hashtable();
  46                         query.ExtractTerms(terms);
  47                         idfExp = similarity.idfExplain(new System.Collections.ArrayList(terms.Values), searcher);
  48                         idf = idfExp.GetIdf();
  49                 }
  50
  51                 public override Query GetQuery()
  52                 {
  53                         return query;
  54                 }
  55                 public override float GetValue()
  56                 {
  57                         return value_Renamed;
  58                 }
  59
  60                 public override float SumOfSquaredWeights()
  61                 {
  62                         queryWeight = idf * query.GetBoost(); // compute query weight
  63                         return queryWeight * queryWeight; // square it
  64                 }
  65
  66                 public override void  Normalize(float queryNorm)
  67                 {
  68                         this.queryNorm = queryNorm;
  69                         queryWeight *= queryNorm; // normalize query weight
  70                         value_Renamed = queryWeight * idf; // idf for document
  71                 }
  72
  73                 public override Scorer Scorer(IndexReader reader, bool scoreDocsInOrder, bool topScorer)
  74                 {
  75                         return new SpanScorer(query.GetSpans(reader), this, similarity, reader.Norms(query.GetField()));
  76                 }
  77
  78                 public override Explanation Explain(IndexReader reader, int doc)
  79                 {
  80
  81                         ComplexExplanation result = new ComplexExplanation();
  82                         result.SetDescription("weight(" + GetQuery() + " in " + doc + "), product of:");
  83                         System.String field = ((SpanQuery) GetQuery()).GetField();
  84
  85                         Explanation idfExpl = new Explanation(idf, "idf(" + field + ": " + idfExp.Explain() + ")");
  86
  87                         // explain query weight
  88                         Explanation queryExpl = new Explanation();
  89                         queryExpl.SetDescription("queryWeight(" + GetQuery() + "), product of:");
  90
  91                         Explanation boostExpl = new Explanation(GetQuery().GetBoost(), "boost");
  92                         if (GetQuery().GetBoost() != 1.0f)
  93                                 queryExpl.AddDetail(boostExpl);
  94                         queryExpl.AddDetail(idfExpl);
  95
  96                         Explanation queryNormExpl = new Explanation(queryNorm, "queryNorm");
  97                         queryExpl.AddDetail(queryNormExpl);
  98
  99                         queryExpl.SetValue(boostExpl.GetValue() * idfExpl.GetValue() * queryNormExpl.GetValue());
 100
 101                         result.AddDetail(queryExpl);
 102
 103                         // explain field weight
 104                         ComplexExplanation fieldExpl = new ComplexExplanation();
 105                         fieldExpl.SetDescription("fieldWeight(" + field + ":" + query.ToString(field) + " in " + doc + "), product of:");
 106
 107                         Explanation tfExpl = Scorer(reader, true, false).Explain(doc);
 108                         fieldExpl.AddDetail(tfExpl);
 109                         fieldExpl.AddDetail(idfExpl);
 110
 111                         Explanation fieldNormExpl = new Explanation();
 112                         byte[] fieldNorms = reader.Norms(field);
 113                         float fieldNorm = fieldNorms != null?Similarity.DecodeNorm(fieldNorms[doc]):1.0f;
 114                         fieldNormExpl.SetValue(fieldNorm);
 115                         fieldNormExpl.SetDescription("fieldNorm(field=" + field + ", doc=" + doc + ")");
 116                         fieldExpl.AddDetail(fieldNormExpl);
 117
 118                         fieldExpl.SetMatch(tfExpl.IsMatch());
 119                         fieldExpl.SetValue(tfExpl.GetValue() * idfExpl.GetValue() * fieldNormExpl.GetValue());
 120
 121                         result.AddDetail(fieldExpl);
 122                         System.Boolean? tempAux = fieldExpl.GetMatch();
 123                         result.SetMatch(tempAux);
 124
 125                         // combine them
 126                         result.SetValue(queryExpl.GetValue() * fieldExpl.GetValue());
 127
 128                         if (queryExpl.GetValue() == 1.0f)
 129                                 return fieldExpl;
 130
 131                         return result;
 132                 }
 133         }
 134 }