beagled/HitRegulator.cs

   1 //
   2 // HitRegulator.cs
   3 //
   4 // Copyright (C) 2005 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a
   9 // copy of this software and associated documentation files (the "Software"),
  10 // to deal in the Software without restriction, including without limitation
  11 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12 // and/or sell copies of the Software, and to permit persons to whom the
  13 // Software is furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in
  16 // all copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24 // DEALINGS IN THE SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Collections;
  29
  30 using Beagle.Util;
  31
  32 namespace Beagle.Daemon {
  33
  34         public class HitRegulator : IQueryResult {
  35
  36                 private int max_n_hits = 100;
  37                 public int MaxHits {
  38                         get { return max_n_hits; }
  39                         set { max_n_hits = (value > 100) ? 100 : value; }
  40                 }
  41
  42                 Queryable queryable;
  43
  44                 ArrayList hit_array = new ArrayList ();
  45                 Hashtable by_uri =UriFu.NewHashtable ();
  46
  47                 const double epsilon = 1e-8;
  48                 double cutoff_score = epsilon;
  49
  50                 public Hashtable added_hits = UriFu.NewHashtable ();
  51                 public Hashtable subtracted_uris = UriFu.NewHashtable ();
  52
  53                 public HitRegulator (Queryable queryable)
  54                 {
  55                         this.queryable = queryable;
  56                 }
  57
  58                 public bool WillReject (double score)
  59                 {
  60                         return score < cutoff_score;
  61                 }
  62
  63                 public bool Add (Hit hit)
  64                 {
  65                         if (WillReject (hit.Score))
  66                                 return false;
  67
  68                         int i = hit_array.BinarySearch (hit);
  69                         if (i < 0)
  70                                 i = ~i;
  71                         hit_array.Insert (i, hit);
  72
  73                         if (hit_array.Count > max_n_hits) {
  74                                 Hit low_hit;
  75                                 for (int j = max_n_hits; j < hit_array.Count; ++j) {
  76                                         low_hit = hit_array [j] as Hit;
  77                                         by_uri.Remove (low_hit.Uri);
  78                                         added_hits.Remove (low_hit.Uri);
  79                                 }
  80                                 hit_array.RemoveRange (max_n_hits, hit_array.Count - max_n_hits);
  81
  82                                 low_hit = hit_array [hit_array.Count - 1] as Hit;
  83                                 cutoff_score = low_hit.Score;
  84                                 //Logger.Log.Debug ("cutoff score is {0:0.00000}", cutoff_score);
  85                         }
  86
  87                         by_uri [hit.Uri] = hit;
  88                         added_hits [hit.Uri] = hit;
  89
  90                         return true;
  91                 }
  92
  93                 public void Subtract (Uri uri)
  94                 {
  95                         if (uri == null)
  96                                 return;
  97
  98                         Hit hit = by_uri [uri] as Hit;
  99                         if (hit != null) {
 100                                 int i = hit_array.BinarySearch (hit);
 101                                 if (i >= 0) {
 102                                         hit_array.RemoveAt (i);
 103                                         added_hits.Remove (uri);
 104                                         subtracted_uris [uri] = uri;
 105                                 }
 106                         }
 107                 }
 108
 109                 public void Flush (QueryResult result)
 110                 {
 111                         ICollection added, subtracted;
 112                         lock (this) {
 113                                 added = added_hits.Values;
 114                                 subtracted = subtracted_uris.Values;
 115                                 added_hits = new Hashtable ();
 116                                 subtracted_uris = new Hashtable ();
 117                         }
 118
 119                         foreach (Hit hit in added) {
 120                                 hit.SourceObject = queryable;
 121                                 hit.SourceObjectName = queryable.Name;
 122                         }
 123
 124                         result.Subtract (subtracted);
 125                         result.Add (added);
 126                 }
 127         }
 128 }