MonoRail/Castle.MonoRail.Framework/Services/DefaultViewComponentRegistry.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.MonoRail.Framework.Services
  16 {
  17         using System;
  18         using System.Collections;
  19
  20         /// <summary>
  21         /// Centralizes the registration and lookup of ViewComponents
  22         /// </summary>
  23         public class DefaultViewComponentRegistry : IViewComponentRegistry
  24         {
  25                 private readonly Hashtable name2Type = new Hashtable(StringComparer.InvariantCultureIgnoreCase);
  26
  27                 #region IViewComponentRegistry
  28
  29                 /// <summary>
  30                 /// Adds the view component.
  31                 /// </summary>
  32                 /// <param name="name">The name that can be used from the view template.</param>
  33                 /// <param name="type">The type.</param>
  34                 public void AddViewComponent(string name, Type type)
  35                 {
  36                         ViewComponentDetailsAttribute details = GetDetails(type);
  37
  38                         if (details != null)
  39                         {
  40                                 name = details.Name;
  41                         }
  42
  43                         name = NormalizeName(name);
  44
  45                         if (name2Type.Contains(name))
  46                         {
  47                                 throw new MonoRailException(String.Format("ViewComponent '{0}' seems to be registered already. " +
  48                                         "This is due to it being registered more than once or a name clash", name));
  49                         }
  50
  51                         if (!typeof(ViewComponent).IsAssignableFrom(type))
  52                         {
  53                                 throw new MonoRailException(String.Format("You tried to register '{0}' as a view component but it " +
  54                                         "doesn't seem the extend the ViewComponent abstract class: {1}", name, type.FullName));
  55                         }
  56
  57                         name2Type[name] = type;
  58                 }
  59
  60                 /// <summary>
  61                 /// Gets the view component.
  62                 /// </summary>
  63                 /// <param name="name">The name.</param>
  64                 /// <returns></returns>
  65                 public Type GetViewComponent(string name)
  66                 {
  67                         name = NormalizeName(name);
  68
  69                         if (!name2Type.Contains(name))
  70                         {
  71                                 throw new MonoRailException(String.Format("ViewComponent '{0}' could not be found. Was it registered? " +
  72                                         "If you have enabled Windsor Integration, then it's likely that you have forgot to register the " +
  73                                         "view component as a Windsor component. If you are sure you did it, then make sure the name used " +
  74                                         "is the component id or the key passed to ViewComponentDetailsAttribute", name));
  75                         }
  76
  77                         return (Type) name2Type[name];
  78                 }
  79
  80                 #endregion
  81
  82                 /// <summary>
  83                 /// Normalizes the name.
  84                 /// </summary>
  85                 /// <param name="name">The name.</param>
  86                 /// <returns></returns>
  87                 private static string NormalizeName(string name)
  88                 {
  89                         if (!name.EndsWith("Component", StringComparison.InvariantCultureIgnoreCase))
  90                         {
  91                                 return name + "Component";
  92                         }
  93                         return name;
  94                 }
  95
  96                 /// <summary>
  97                 /// Gets the details.
  98                 /// </summary>
  99                 /// <param name="type">The type.</param>
 100                 /// <returns></returns>
 101                 private static ViewComponentDetailsAttribute GetDetails(Type type)
 102                 {
 103                         // TODO: Add cache here, GetCustomAttributes is a lengthy call.
 104
 105                         object[] attributes = type.GetCustomAttributes(typeof(ViewComponentDetailsAttribute), false);
 106
 107                         if (attributes.Length == 0)
 108                         {
 109                                 return null;
 110                         }
 111
 112                         return (ViewComponentDetailsAttribute)attributes[0];
 113                 }
 114         }
 115 }