InversionOfControl/Castle.MicroKernel/Lifestyle/SingletonLifestyleManager.cs

   1 // Copyright 2004-2008 Castle Project - http://www.castleproject.org/
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 namespace Castle.MicroKernel.Lifestyle
  16 {
  17         using System;
  18
  19         /// <summary>
  20         /// Summary description for SingletonLifestyleManager.
  21         /// </summary>
  22         [Serializable]
  23         public class SingletonLifestyleManager : AbstractLifestyleManager
  24         {
  25                 private volatile Object instance;
  26
  27                 public override void Dispose()
  28                 {
  29                         if (instance != null) base.Release( instance );
  30                 }
  31
  32                 public override object Resolve(CreationContext context)
  33                 {
  34                         if (instance == null)
  35                         {
  36                                 lock (ComponentActivator)
  37                                 {
  38                                         if (instance == null)
  39                                         {
  40                                                 instance = base.Resolve(context);
  41                                         }
  42                                 }
  43                         }
  44
  45                         return instance;
  46                 }
  47
  48                 public override void Release( object instance )
  49                 {
  50                         // Do nothing
  51                 }
  52         }
  53 }