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         public class SurrogateSelector : ISurrogateSelector
  39         {
  40                 // Fields
  41                 Hashtable Surrogates = new Hashtable ();
  42                 ISurrogateSelector nextSelector = null;
  43
  44                 // Constructor
  45                 public SurrogateSelector()
  46                         : base ()
  47                 {
  48                 }
  49
  50                 // Methods
  51                 public virtual void AddSurrogate (Type type,
  52                           StreamingContext context, ISerializationSurrogate surrogate)
  53                 {
  54                         if (type == null || surrogate == null)
  55                                 throw new ArgumentNullException ("Null reference.");
  56
  57                         string currentKey = type.FullName + "#" + context.ToString ();
  58
  59                         if (Surrogates.ContainsKey (currentKey))
  60                                 throw new ArgumentException ("A surrogate for " + type.FullName + " already exists.");
  61
  62                         Surrogates.Add (currentKey, surrogate);
  63                 }
  64
  65                 public virtual void ChainSelector (ISurrogateSelector selector)
  66                 {
  67                         if (selector == null)
  68                                 throw new ArgumentNullException ("Selector is null.");
  69
  70                         // Chain the selector at the beggining of the chain
  71                         // since "The last selector added to the list will be the first one checked"
  72                         // (from MS docs)
  73
  74                         if (nextSelector != null)
  75                                 selector.ChainSelector (nextSelector);
  76
  77                         nextSelector = selector;
  78                 }
  79
  80                 public virtual ISurrogateSelector GetNextSelector ()
  81                 {
  82                         return nextSelector;
  83                 }
  84
  85                 public virtual ISerializationSurrogate GetSurrogate (Type type,
  86                              StreamingContext context, out ISurrogateSelector selector)
  87                 {
  88                         if (type == null)
  89                                 throw new ArgumentNullException ("type is null.");
  90
  91                         // Check this selector, and if the surrogate is not found,
  92                         // check the chained selectors
  93
  94                         string key = type.FullName + "#" + context.ToString ();
  95                         ISerializationSurrogate surrogate = (ISerializationSurrogate) Surrogates [key];
  96
  97                         if (surrogate != null) {
  98                                 selector = this;
  99                                 return surrogate;
 100                         }
 101
 102                         if (nextSelector != null)
 103                                 return nextSelector.GetSurrogate (type, context, out selector);
 104                         else {
 105                                 selector = null;
 106                                 return null;
 107                         }
 108                 }
 109
 110                 public virtual void RemoveSurrogate (Type type, StreamingContext context)
 111                 {
 112                         if (type == null)
 113                                 throw new ArgumentNullException ("type is null.");
 114
 115                         string key = type.FullName + "#" + context.ToString ();
 116                         Surrogates.Remove (key);
 117                 }
 118         }
 119 }