beagled/Lucene.Net/Search/NonMatchingScorer.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
  17 using System;
  18
  19 namespace Lucene.Net.Search
  20 {
  21
  22         /// <summary>A scorer that matches no document at all. </summary>
  23         class NonMatchingScorer : Scorer
  24         {
  25                 public NonMatchingScorer() : base(null)
  26                 {
  27                 } // no similarity used
  28
  29                 public override int Doc()
  30                 {
  31                         throw new System.NotSupportedException();
  32                 }
  33
  34                 public override bool Next()
  35                 {
  36                         return false;
  37                 }
  38
  39                 public override float Score()
  40                 {
  41                         throw new System.NotSupportedException();
  42                 }
  43
  44                 public override bool SkipTo(int target)
  45                 {
  46                         return false;
  47                 }
  48
  49                 public override Explanation Explain(int doc)
  50                 {
  51                         Explanation e = new Explanation();
  52                         e.SetDescription("No document matches.");
  53                         return e;
  54                 }
  55         }
  56 }