MonoRail/Castle.MonoRail.Framework/Services/DefaultHelperFactory.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.Reflection;
  19
  20         /// <summary>
  21         ///
  22         /// </summary>
  23         public class DefaultHelperFactory : IHelperFactory
  24         {
  25                 /// <summary>
  26                 /// Creates the helper.
  27                 /// </summary>
  28                 /// <param name="helperType">Type of the helper.</param>
  29                 /// <param name="engineContext">The engine context.</param>
  30                 /// <param name="initialized">if set to <c>true</c> the helper is already initialized.</param>
  31                 /// <returns></returns>
  32                 public virtual object Create(Type helperType, IEngineContext engineContext, out bool initialized)
  33                 {
  34                         if (helperType == null)
  35                         {
  36                                 throw new ArgumentNullException("helperType");
  37                         }
  38                         if (engineContext == null)
  39                         {
  40                                 throw new ArgumentNullException("engineContext");
  41                         }
  42
  43                         initialized = false;
  44
  45                         object helper;
  46
  47                         ConstructorInfo constructorInfo =
  48                                 helperType.GetConstructor(BindingFlags.Public, null, new Type[] {typeof(IEngineContext)}, null);
  49
  50                         try
  51                         {
  52                                 if (constructorInfo != null)
  53                                 {
  54                                         helper = Activator.CreateInstance(helperType, new object[] { engineContext });
  55                                 }
  56                                 else
  57                                 {
  58                                         helper = Activator.CreateInstance(helperType);
  59                                 }
  60                         }
  61                         catch(Exception ex)
  62                         {
  63                                 throw new MonoRailException("Could not instantiate helper " + helperType.FullName, ex);
  64                         }
  65
  66                         return helper;
  67                 }
  68         }
  69 }