Components/DictionaryAdapter/Castle.Components.DictionaryAdapter/Attributes/DictionaryAdapterPropertyBinder.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.Components.DictionaryAdapter
  16 {
  17         using System;
  18         using System.Collections;
  19         using System.Reflection;
  20
  21         /// <summary>
  22         /// Base class for property binders which defines the bidirectional conversion methods.
  23         /// </summary>
  24         public abstract class DictionaryAdapterPropertyBinder
  25         {
  26                 /// <summary>
  27                 /// Performs the dictionary -> interface conversion for when client code is attempting to read out
  28                 /// of the "adapted" dictionary.
  29                 /// </summary>
  30                 /// <param name="value">The string value to convert to the property type.</param>
  31                 /// <returns>The converted value.</returns>
  32                 public object ConvertFromDictionary(object value)
  33                 {
  34                         AssertDictionaryValueHasExpectedType(value, DictionaryType);
  35                         return PerformConversionFromDictionary(value);
  36                 }
  37
  38
  39                 /// <summary>
  40                 /// Gets the type of the dictionary.
  41                 /// </summary>
  42                 /// <value>The type of the dictionary.</value>
  43                 protected abstract Type DictionaryType { get; }
  44
  45                 /// <summary>
  46                 /// Performs the conversion from dictionary.
  47                 /// </summary>
  48                 /// <param name="value">The value.</param>
  49                 /// <returns></returns>
  50                 protected abstract object PerformConversionFromDictionary(object value);
  51
  52                 /// <summary>
  53                 /// Performs the interface -> dictionary conversion for when the client code is attempting to write
  54                 /// into the "adapted" dictionary.
  55                 /// </summary>
  56                 /// <param name="value">The value to convert.</param>
  57                 /// <returns>The converted value.</returns>
  58                 public abstract object ConvertFromInterface(object value);
  59
  60                 /// <summary>
  61                 /// Asserts that the type in the dictionary is the type expected, and if not, throws a meaningful
  62                 /// exception rather than InvalidCastException.
  63                 /// </summary>
  64                 /// <param name="value"></param>
  65                 /// <param name="interfaceType"></param>
  66                 protected void AssertDictionaryValueHasExpectedType(object value, Type interfaceType)
  67                 {
  68                         if (value.GetType() != interfaceType)
  69                         {
  70                                 throw new DictionaryAdapterPropertyBindingException(GetType(), value, interfaceType);
  71                         }
  72                 }
  73         }
  74 }