InversionOfControl/Castle.MicroKernel/SubSystems/Conversion/Converters/AttributeAwareConverter.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.using System;
  14
  15 namespace Castle.MicroKernel.SubSystems.Conversion
  16 {
  17         using System;
  18         using Castle.MicroKernel.SubSystems.Conversion;
  19
  20         /// <summary>
  21         /// Looks for a <see cref="ConvertibleAttribute"/> on the type to be converted.
  22         /// If found, the TypeConverter defined by the attribute is used to perform the conversion.
  23         /// </summary>
  24         public class AttributeAwareConverter : AbstractTypeConverter
  25         {
  26                 #region ITypeConverter Member
  27
  28                 public override bool CanHandleType(Type type)
  29                 {
  30                         ITypeConverter converter = TryGetConverterInstance(type);
  31
  32                         if (converter != null)
  33                         {
  34                                 return converter.CanHandleType(type);
  35                         }
  36                         else
  37                         {
  38                                 return false;
  39                         }
  40                 }
  41
  42                 public override object PerformConversion(string value, Type targetType)
  43                 {
  44                         ITypeConverter converter = GetConverterInstance(targetType);
  45                         return converter.PerformConversion(value, targetType);
  46                 }
  47
  48                 public override object PerformConversion(Castle.Core.Configuration.IConfiguration configuration, Type targetType)
  49                 {
  50                         ITypeConverter converter = GetConverterInstance(targetType);
  51                         return converter.PerformConversion(configuration, targetType);
  52                 }
  53
  54                 #endregion
  55
  56                 private ITypeConverter TryGetConverterInstance(Type type)
  57                 {
  58                         ITypeConverter converter = null;
  59
  60                         ConvertibleAttribute attr = (ConvertibleAttribute)
  61                                 Attribute.GetCustomAttribute(type, typeof(ConvertibleAttribute));
  62
  63                         if (attr != null)
  64                         {
  65                                 converter = (ITypeConverter) Activator.CreateInstance(attr.ConverterType);
  66                                 converter.Context = Context;
  67                         }
  68
  69                         return converter;
  70                 }
  71
  72                 private ITypeConverter GetConverterInstance(Type type)
  73                 {
  74                         ITypeConverter converter = TryGetConverterInstance(type);
  75
  76                         if (converter == null)
  77                         {
  78                                 throw new InvalidOperationException("Type " + type.Name + " does not have a Convertible attribute.");
  79                         }
  80
  81                         return converter;
  82                 }
  83         }
  84 }