mcs/class/System.Web/System.Web.Caching/AggregateCacheDependency.cs

   1 //
   2 // System.Web.Compilation.AggregateCacheDependency
   3 //
   4 // Authors:
   5 //   Marek Habersack (grendello@gmail.com)
   6 //
   7 // (C) 2006 Marek Habersack
   8 //
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Collections.Generic;
  32 using System.Text;
  33 using System.Web;
  34
  35 namespace System.Web.Caching
  36 {
  37         public sealed class AggregateCacheDependency : CacheDependency
  38         {
  39                 object dependenciesLock = new object();
  40                 List <CacheDependency> dependencies;
  41
  42                 public AggregateCacheDependency ()
  43                 {
  44                         FinishInit ();
  45                 }
  46
  47                 public void Add (params CacheDependency [] dependencies)
  48                 {
  49                         if (dependencies == null)
  50                                 throw new ArgumentNullException ("dependencies");
  51                         if (dependencies.Length == 0)
  52                                 return;
  53
  54                         bool somethingChanged = false;
  55                         foreach (CacheDependency dep in dependencies)
  56                                 if (dep == null || dep.IsUsed)
  57                                         throw new InvalidOperationException ("Cache dependency already in use");
  58                                 else if (!somethingChanged && dep != null && dep.HasChanged)
  59                                         somethingChanged = true;
  60
  61                         lock (dependenciesLock) {
  62                                 if (this.dependencies == null)
  63                                         this.dependencies = new List <CacheDependency> (dependencies.Length);
  64                                 foreach (CacheDependency dep in dependencies)
  65                                         if (dep != null)
  66                                                 dep.DependencyChanged += new EventHandler (OnAnyChanged);
  67
  68                                 this.dependencies.AddRange (dependencies);
  69                                 base.Start = DateTime.UtcNow;
  70                         }
  71                         if (somethingChanged)
  72                                 base.NotifyDependencyChanged (this, null);
  73                 }
  74
  75                 public override string GetUniqueID ()
  76                 {
  77                         if (dependencies == null || dependencies.Count == 0)
  78                                 return null;
  79
  80                         StringBuilder sb = new StringBuilder ();
  81                         lock (dependenciesLock) {
  82                                 string depid = null;
  83                                 foreach (CacheDependency dep in dependencies) {
  84                                         depid = dep.GetUniqueID ();
  85                                         if (String.IsNullOrEmpty (depid))
  86                                                 return null;
  87                                         sb.Append (depid);
  88                                         sb.Append (';');
  89                                 }
  90                         }
  91                         return sb.ToString ();
  92                 }
  93
  94                 protected override void DependencyDispose ()
  95                 {
  96                         // MSDN doesn't document it as being part of the class, but assembly
  97                         // comparison shows that it does exist in this type, so we're just calling
  98                         // the base class here
  99                         base.DependencyDispose ();
 100                 }
 101
 102                 internal override void DependencyDisposeInternal ()
 103                 {
 104                         if (dependencies != null && dependencies.Count > 0)
 105                                 foreach (CacheDependency dep in dependencies)
 106                                         dep.DependencyChanged -= new EventHandler (OnAnyChanged);
 107                 }
 108
 109                 void OnAnyChanged (object sender, EventArgs args)
 110                 {
 111                         base.NotifyDependencyChanged (sender, args);
 112                 }
 113         }
 114 }
 115
 116
 117