mcs/class/corlib/System.Collections.ObjectModel/KeyedCollection.cs

   1 // -*- Mode: csharp; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
   2 //
   3 // System.Collections.ObjectModel.KeyedCollection
   4 //
   5 // Author:
   6 //    Zoltan Varga (vargaz@gmail.com)
   7 //
   8 // (C) 2005 Novell, Inc.
   9 //
  10
  11 //
  12 // Copyright (C) 2005 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 #if NET_2_0
  35 using System;
  36 using System.Collections.Generic;
  37 using System.Runtime.InteropServices;
  38
  39 namespace System.Collections.ObjectModel
  40 {
  41         [ComVisible(false)]
  42         [Serializable]
  43         public abstract class KeyedCollection<TKey, TItem> : Collection<TItem>
  44         {
  45                 private Dictionary<TKey, TItem> dictionary;
  46                 private IEqualityComparer<TKey> comparer;
  47                 private int dictionaryCreationThreshold;
  48
  49                 protected KeyedCollection ()
  50                         : this (null, 0)
  51                 {
  52                 }
  53
  54                 protected KeyedCollection (IEqualityComparer<TKey> comparer)
  55                         : this(comparer, 0)
  56                 {
  57                 }
  58
  59                 protected KeyedCollection (IEqualityComparer<TKey> comparer, int dictionaryCreationThreshold)
  60                 {
  61                         if (comparer != null)
  62                                 this.comparer = comparer;
  63                         else
  64                                 this.comparer = EqualityComparer<TKey>.Default;
  65
  66                         this.dictionaryCreationThreshold = dictionaryCreationThreshold;
  67
  68                         if (dictionaryCreationThreshold == 0)
  69                                 dictionary = new Dictionary<TKey, TItem> (this.comparer);
  70                 }
  71
  72                 public bool Contains (TKey key)
  73                 {
  74                         if (dictionary != null)
  75                                 return dictionary.ContainsKey (key);
  76                         return IndexOfKey (key) >= 0;
  77                 }
  78
  79                 private int IndexOfKey (TKey key)
  80                 {
  81                         for (int i = Count - 1; i >= 0; i--)
  82                         {
  83                                 TKey lkey = GetKeyForItem (this [i]);
  84                                 if (comparer.Equals (key, lkey))
  85                                         return i;
  86                         }
  87                         return -1;
  88                 }
  89
  90                 public bool Remove (TKey key)
  91                 {
  92                         TItem item;
  93                         if (dictionary != null)
  94                         {
  95                                 if (dictionary.TryGetValue (key, out item))
  96                                         return base.Remove(item);
  97                                 else
  98                                         return false;
  99                         }
 100
 101                         int idx = IndexOfKey (key);
 102
 103                         if (idx == -1)
 104                                 return false;
 105
 106                         RemoveAt(idx);
 107                         return true;
 108                 }
 109
 110                 public IEqualityComparer<TKey> Comparer {
 111                         get {
 112                                 return comparer;
 113                         }
 114                 }
 115
 116                 public TItem this [TKey key] {
 117                         get {
 118                                 if (dictionary != null)
 119                                         return dictionary [key];
 120
 121                                 int idx = IndexOfKey (key);
 122                                 if (idx >= 0)
 123                                         return base [idx];
 124                                 else
 125                                         throw new KeyNotFoundException();
 126                         }
 127                 }
 128
 129                 protected void ChangeItemKey (TItem item, TKey newKey)
 130                 {
 131                         if (!Contains(item)) throw new ArgumentException();
 132
 133                         TKey oldKey = GetKeyForItem (item);
 134                         if (comparer.Equals (oldKey, newKey)) return;
 135
 136                         if (Contains (newKey)) throw new ArgumentException();
 137                         if (dictionary != null)
 138                         {
 139
 140                                 if (!dictionary.Remove (oldKey))
 141                                         throw new ArgumentException();
 142
 143                                 dictionary.Add (newKey, item);
 144                         }
 145                 }
 146
 147                 protected override void ClearItems ()
 148                 {
 149                         if (dictionary != null)
 150                         {
 151                                 dictionary.Clear();
 152                         }
 153
 154                         base.ClearItems ();
 155                 }
 156
 157                 protected abstract TKey GetKeyForItem (TItem item);
 158
 159                 protected override void InsertItem (int index, TItem item)
 160                 {
 161                         if (dictionary != null)
 162                         {
 163                                 dictionary.Add (GetKeyForItem (item), item);
 164                         }
 165                         else
 166                         {
 167                                 if (dictionaryCreationThreshold != -1 && Count + 1 > dictionaryCreationThreshold)
 168                                 {
 169                                         dictionary = new Dictionary<TKey, TItem> (comparer);
 170
 171                                         for (int i = Count - 1; i >= 0; i--)
 172                                         {
 173                                                 TItem dictitem = this[i];
 174                                                 dictionary.Add(GetKeyForItem(dictitem), dictitem);
 175                                         }
 176
 177                                         dictionary.Add (GetKeyForItem (item), item);
 178                                 }
 179                         }
 180                         base.InsertItem (index, item);
 181                 }
 182
 183                 protected override void RemoveItem (int index)
 184                 {
 185                         if (dictionary != null)
 186                         {
 187                                 TKey key = GetKeyForItem (this [index]);
 188                                 dictionary.Remove (key);
 189                         }
 190                         base.RemoveItem (index);
 191                 }
 192
 193                 protected override void SetItem (int index, TItem item)
 194                 {
 195                         if (dictionary != null)
 196                         {
 197                                 dictionary.Remove (GetKeyForItem (this [index]));
 198                                 dictionary.Add (GetKeyForItem (item), item);
 199                         }
 200                         base.SetItem (index, item);
 201                 }
 202
 203                 protected IDictionary<TKey, TItem> Dictionary {
 204                         get {
 205                                 return dictionary;
 206                         }
 207                 }
 208         }
 209 }
 210 #endif