MonoRail/Castle.MonoRail.Framework/Attributes/FilterAttribute.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.MonoRail.Framework
  16 {
  17         using System;
  18         using Castle.MonoRail.Framework.Descriptors;
  19
  20         /// <summary>
  21         /// Decorates a controller associating a <see cref="IFilter"/>
  22         /// implementation with it. More than one can be associated.
  23         /// </summary>
  24         /// <remarks>
  25         /// If more than one filter is associate with an action (or controller and
  26         /// action), the order of execution cannot be predicted. In this case
  27         /// use <see cref="ExecutionOrder"/> to define the order of execution.
  28         /// </remarks>
  29         [AttributeUsage(AttributeTargets.Class, AllowMultiple=true, Inherited=true), Serializable]
  30         public class FilterAttribute : Attribute, IFilterDescriptorBuilder
  31         {
  32                 private readonly Type filterType;
  33                 private readonly ExecuteEnum when;
  34                 private int executionOrder = Int32.MaxValue;
  35
  36                 /// <summary>
  37                 /// Constructs a FilterAttribute associating
  38                 /// the filter type and when the filter should be invoked.
  39                 /// </summary>
  40                 /// <param name="when">When to execute the filter</param>
  41                 /// <param name="filterType">The filter implementation</param>
  42                 public FilterAttribute(ExecuteEnum when, Type filterType)
  43                 {
  44                         if (!typeof(IFilter).IsAssignableFrom(filterType))
  45                         {
  46                                 throw new ArgumentException("The specified type does not implement IFilter");
  47                         }
  48
  49                         this.filterType = filterType;
  50                         this.when = when;
  51                 }
  52
  53                 /// <summary>
  54                 /// Gets the filter implementation type
  55                 /// </summary>
  56                 public Type FilterType
  57                 {
  58                         get { return filterType; }
  59                 }
  60
  61                 /// <summary>
  62                 /// Gets when to run the filter
  63                 /// </summary>
  64                 public ExecuteEnum When
  65                 {
  66                         get { return when; }
  67                 }
  68
  69                 /// <summary>
  70                 /// Gets or sets the filter execution order.
  71                 /// The lower the value, the higher the priority
  72                 /// </summary>
  73                 public int ExecutionOrder
  74                 {
  75                         get { return executionOrder; }
  76                         set { executionOrder = value; }
  77                 }
  78
  79                 /// <summary>
  80                 /// Implementation of <see cref="IFilterDescriptorBuilder"/>.
  81                 /// Returns the descriptor for this filter association.
  82                 /// </summary>
  83                 /// <returns></returns>
  84                 public FilterDescriptor[] BuildFilterDescriptors()
  85                 {
  86                         return new FilterDescriptor[] { new FilterDescriptor(FilterType, when, executionOrder, this) };
  87                 }
  88         }
  89 }