class/corlib/System.Runtime.Remoting.Contexts/ContextAttribute.cs

   1 //
   2 // System.Runtime.Remoting.Contexts.ContextAttribute.cs
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) Ximian, Inc.  http://www.ximian.com
   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.Runtime.Remoting.Activation;
  34 using System.Collections;
  35
  36 namespace System.Runtime.Remoting.Contexts {
  37
  38         [AttributeUsage (AttributeTargets.Class)]
  39         [Serializable]
  40         [System.Runtime.InteropServices.ComVisible (true)]
  41         public class ContextAttribute : Attribute, IContextAttribute, IContextProperty {
  42                 protected string AttributeName;
  43
  44                 public ContextAttribute (string name)
  45                 {
  46                         AttributeName = name;
  47                 }
  48
  49                 public virtual string Name {
  50                         get {
  51                                 return AttributeName;
  52                         }
  53                 }
  54
  55                 public override bool Equals (object o)
  56                 {
  57                         if (o == null)
  58                                 return false;
  59
  60                         if (!(o is ContextAttribute))
  61                                 return false;
  62
  63                         ContextAttribute ca = (ContextAttribute) o;
  64
  65                         if (ca.AttributeName != AttributeName)
  66                                 return false;
  67
  68                         return true;
  69                 }
  70
  71                 public virtual void Freeze (Context newContext)
  72                 {
  73                 }
  74
  75                 public override int GetHashCode ()
  76                 {
  77                         if (AttributeName == null)
  78                                 return 0;
  79
  80                         return AttributeName.GetHashCode ();
  81                 }
  82
  83                 /// <summary>
  84                 ///    Adds the current context property to the IConstructionCallMessage
  85                 /// </summary>
  86                 public virtual void GetPropertiesForNewContext (IConstructionCallMessage ctorMsg)
  87                 {
  88                         if (ctorMsg == null)
  89                                 throw new ArgumentNullException ("ctorMsg");
  90
  91                         IList list = ctorMsg.ContextProperties;
  92
  93                         list.Add (this);
  94                 }
  95
  96                 // <summary>
  97                 //   True whether the context arguments satisfies the requirements
  98                 //   of the current context.
  99                 // </summary>
 100                 public virtual bool IsContextOK (Context ctx, IConstructionCallMessage ctorMsg)
 101                 {
 102                         if (ctorMsg == null)
 103                                 throw new ArgumentNullException ("ctorMsg");
 104                         if (ctx == null)
 105                                 throw new ArgumentNullException ("ctx");
 106
 107                         if (!ctorMsg.ActivationType.IsContextful)
 108                                 return true;
 109
 110                         IContextProperty p = ctx.GetProperty (AttributeName);
 111                         if (p == null)
 112                                 return false;
 113
 114                         if (this != p)
 115                                 return false;
 116
 117                         return true;
 118                 }
 119
 120                 public virtual bool IsNewContextOK (Context newCtx)
 121                 {
 122                         return true;
 123                 }
 124         }
 125 }