mcs/class/corlib/System.Runtime.Serialization/SurrogateSelector.cs

   1 //
   2 // System.Runtime.Serialization.SurrogateSelector.cs
   3 //
   4 // Author: Duncan Mak (duncan@ximian.com)
   5 //         Lluis Sanchez (lsg@ctv.es)
   6 //
   7 // (C) Ximian, Inc.
   8 //
   9
  10 //
  11 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.Collections;
  35
  36 namespace System.Runtime.Serialization
  37 {
  38 #if NET_2_0
  39         [System.Runtime.InteropServices.ComVisibleAttribute (true)]
  40 #endif
  41         public class SurrogateSelector : ISurrogateSelector
  42         {
  43                 // Fields
  44                 Hashtable Surrogates = new Hashtable ();
  45                 ISurrogateSelector nextSelector = null;
  46
  47                 // Constructor
  48                 public SurrogateSelector()
  49                         : base ()
  50                 {
  51                 }
  52
  53                 // Methods
  54                 public virtual void AddSurrogate (Type type,
  55                           StreamingContext context, ISerializationSurrogate surrogate)
  56                 {
  57                         if (type == null || surrogate == null)
  58                                 throw new ArgumentNullException ("Null reference.");
  59
  60                         string currentKey = type.FullName + "#" + context.ToString ();
  61
  62                         if (Surrogates.ContainsKey (currentKey))
  63                                 throw new ArgumentException ("A surrogate for " + type.FullName + " already exists.");
  64
  65                         Surrogates.Add (currentKey, surrogate);
  66                 }
  67
  68                 public virtual void ChainSelector (ISurrogateSelector selector)
  69                 {
  70                         if (selector == null)
  71                                 throw new ArgumentNullException ("Selector is null.");
  72
  73                         // Chain the selector at the beggining of the chain
  74                         // since "The last selector added to the list will be the first one checked"
  75                         // (from MS docs)
  76
  77                         if (nextSelector != null)
  78                                 selector.ChainSelector (nextSelector);
  79
  80                         nextSelector = selector;
  81                 }
  82
  83                 public virtual ISurrogateSelector GetNextSelector ()
  84                 {
  85                         return nextSelector;
  86                 }
  87
  88                 public virtual ISerializationSurrogate GetSurrogate (Type type,
  89                              StreamingContext context, out ISurrogateSelector selector)
  90                 {
  91                         if (type == null)
  92                                 throw new ArgumentNullException ("type is null.");
  93
  94                         // Check this selector, and if the surrogate is not found,
  95                         // check the chained selectors
  96
  97                         string key = type.FullName + "#" + context.ToString ();
  98                         ISerializationSurrogate surrogate = (ISerializationSurrogate) Surrogates [key];
  99
 100                         if (surrogate != null) {
 101                                 selector = this;
 102                                 return surrogate;
 103                         }
 104
 105                         if (nextSelector != null)
 106                                 return nextSelector.GetSurrogate (type, context, out selector);
 107                         else {
 108                                 selector = null;
 109                                 return null;
 110                         }
 111                 }
 112
 113                 public virtual void RemoveSurrogate (Type type, StreamingContext context)
 114                 {
 115                         if (type == null)
 116                                 throw new ArgumentNullException ("type is null.");
 117
 118                         string key = type.FullName + "#" + context.ToString ();
 119                         Surrogates.Remove (key);
 120                 }
 121         }
 122 }