InversionOfControl/Castle.MicroKernel/Handlers/ParentHandlerWithChildResolver.cs

   1 // Copyright 2004-2007 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.Handlers
  16 {
  17         using System;
  18
  19         using Castle.Core;
  20
  21         /// <summary>
  22         /// Redirects resolution to the main resolver, and if not found uses
  23         /// the parent handler.
  24         /// </summary>
  25         public class ParentHandlerWithChildResolver : IHandler, IDisposable
  26         {
  27                 private readonly IHandler parentHandler;
  28                 private readonly ISubDependencyResolver childResolver;
  29
  30                 /// <summary>
  31                 /// Initializes a new instance of the <see cref="ParentHandlerWithChildResolver"/> class.
  32                 /// </summary>
  33                 /// <param name="parentHandler">The parent handler.</param>
  34                 /// <param name="childResolver">The child resolver.</param>
  35                 public ParentHandlerWithChildResolver(IHandler parentHandler, ISubDependencyResolver childResolver)
  36                 {
  37                         if (parentHandler == null) throw new ArgumentNullException("parentHandler");
  38                         if (childResolver == null) throw new ArgumentNullException("childResolver");
  39
  40                         this.parentHandler = parentHandler;
  41                         parentHandler.OnHandlerStateChanged += new HandlerStateDelegate(RaiseHandlerStateChanged);
  42                         this.childResolver = childResolver;
  43                 }
  44
  45                 #region ISubDependencyResolver Members
  46
  47                 public virtual object Resolve(CreationContext context, ISubDependencyResolver parentResolver, ComponentModel model, DependencyModel dependency)
  48                 {
  49                         object value = childResolver.Resolve(context, null, model, dependency);
  50
  51                         if (value == null)
  52                         {
  53                                 value = parentHandler.Resolve(context, parentResolver, model, dependency);
  54                         }
  55
  56                         return value;
  57                 }
  58
  59                 public virtual bool CanResolve(CreationContext context, ISubDependencyResolver parentResolver, ComponentModel model, DependencyModel dependency)
  60                 {
  61                         bool canResolve = childResolver.CanResolve(context, null, model, dependency);
  62
  63                         if (!canResolve)
  64                         {
  65                                 canResolve = parentHandler.CanResolve(context, parentResolver, model, dependency);
  66                         }
  67
  68                         return canResolve;
  69                 }
  70
  71                 #endregion
  72
  73                 #region IHandler Members
  74
  75                 public virtual void Init(IKernel kernel)
  76                 {
  77                         throw new NotImplementedException();
  78                 }
  79
  80                 public virtual object Resolve(CreationContext context)
  81                 {
  82                         return parentHandler.Resolve(context);
  83                 }
  84
  85                 public virtual void Release(object instance)
  86                 {
  87                         parentHandler.Release(instance);
  88                 }
  89
  90                 public virtual HandlerState CurrentState
  91                 {
  92                         get { return parentHandler.CurrentState; }
  93                 }
  94
  95                 public virtual ComponentModel ComponentModel
  96                 {
  97                         get { return parentHandler.ComponentModel; }
  98                 }
  99
 100                 public event HandlerStateDelegate OnHandlerStateChanged;
 101
 102                 protected virtual void RaiseHandlerStateChanged(object s, EventArgs e)
 103                 {
 104                         if (OnHandlerStateChanged != null)
 105                         {
 106                                 OnHandlerStateChanged(s, e);
 107                         }
 108                 }
 109
 110                 public virtual void AddCustomDependencyValue(string key, object value)
 111                 {
 112                         parentHandler.AddCustomDependencyValue(key, value);
 113                 }
 114
 115                 public virtual void RemoveCustomDependencyValue(string key)
 116                 {
 117                         parentHandler.RemoveCustomDependencyValue(key);
 118                 }
 119
 120                 public virtual bool HasCustomParameter(string key)
 121                 {
 122                         return parentHandler.HasCustomParameter(key);
 123                 }
 124
 125                 #endregion
 126
 127                 #region IDisposable Members
 128
 129                 public void Dispose()
 130                 {
 131                         Dispose(true);
 132                 }
 133
 134                 protected virtual void Dispose(bool disposing)
 135                 {
 136                         if (disposing)
 137                         {
 138                                 if (parentHandler != null)
 139                                 {
 140                                         parentHandler.OnHandlerStateChanged -= new HandlerStateDelegate(RaiseHandlerStateChanged);
 141                                 }
 142                         }
 143                 }
 144
 145                 #endregion
 146         }
 147 }