mcs/class/System.Xaml/System.Xaml.Schema/XamlValueConverter.cs

   1 //
   2 // Copyright (C) 2010 Novell Inc. http://novell.com
   3 //
   4 // Permission is hereby granted, free of charge, to any person obtaining
   5 // a copy of this software and associated documentation files (the
   6 // "Software"), to deal in the Software without restriction, including
   7 // without limitation the rights to use, copy, modify, merge, publish,
   8 // distribute, sublicense, and/or sell copies of the Software, and to
   9 // permit persons to whom the Software is furnished to do so, subject to
  10 // the following conditions:
  11 //
  12 // The above copyright notice and this permission notice shall be
  13 // included in all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  19 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  20 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  21 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  22 //
  23 using System;
  24 using System.Collections.Generic;
  25
  26 namespace System.Xaml.Schema
  27 {
  28         public class XamlValueConverter<TConverterBase> : IEquatable<XamlValueConverter<TConverterBase>>
  29                 where TConverterBase : class
  30         {
  31                 public XamlValueConverter (Type converterType, XamlType targetType)
  32                         : this (converterType, targetType, null)
  33                 {
  34                 }
  35
  36                 public XamlValueConverter (Type converterType, XamlType targetType, string name)
  37                 {
  38                         if (converterType == null && targetType == null && name == null)
  39                                 throw new ArgumentException ("Either of converterType, targetType or name must be non-null");
  40                         ConverterType = converterType;
  41                         TargetType = targetType;
  42                         Name = name;
  43                 }
  44
  45                 TConverterBase converter_instance;
  46                 public TConverterBase ConverterInstance {
  47                         get {
  48                                 if (converter_instance == null)
  49                                         converter_instance = CreateInstance ();
  50                                 return converter_instance;
  51                         }
  52                 }
  53                 public Type ConverterType { get; private set; }
  54                 public string Name { get; private set; }
  55                 public XamlType TargetType { get; private set; }
  56
  57
  58                 public static bool operator == (XamlValueConverter<TConverterBase> left, XamlValueConverter<TConverterBase> right)
  59                 {
  60                         return IsNull (left) ? IsNull (right) : left.Equals (right);
  61                 }
  62
  63                 static bool IsNull (XamlValueConverter<TConverterBase> a)
  64                 {
  65                         return Object.ReferenceEquals (a, null);
  66                 }
  67
  68                 public static bool operator != (XamlValueConverter<TConverterBase> left, XamlValueConverter<TConverterBase> right)
  69                 {
  70                         return IsNull (left) ? !IsNull (right) : IsNull (right) || left.ConverterType != right.ConverterType || left.TargetType != right.TargetType || left.Name != right.Name;
  71                 }
  72
  73                 public bool Equals (XamlValueConverter<TConverterBase> other)
  74                 {
  75                         return !IsNull (other) && ConverterType == other.ConverterType && TargetType == other.TargetType && Name == other.Name;
  76                 }
  77
  78                 public override bool Equals (object obj)
  79                 {
  80                         var a = obj as XamlValueConverter<TConverterBase>;
  81                         return Equals (a);
  82                 }
  83
  84                 protected virtual TConverterBase CreateInstance ()
  85                 {
  86                         if (ConverterType == null)
  87                                 return null;
  88
  89                         if (!typeof (TConverterBase).IsAssignableFrom (ConverterType))
  90                                 throw new XamlSchemaException (String.Format ("ConverterType '{0}' is not derived from '{1}' type", ConverterType, typeof (TConverterBase)));
  91
  92                         return (TConverterBase) Activator.CreateInstance (ConverterType);
  93                 }
  94
  95                 public override int GetHashCode ()
  96                 {
  97                         var ret = ConverterType != null ? ConverterType.GetHashCode () : 0;
  98                         ret <<= 5;
  99                         if (TargetType != null)
 100                                 ret += TargetType.GetHashCode ();
 101                         ret <<= 5;
 102                         if (Name != null)
 103                                 ret += Name.GetHashCode ();
 104                         return ret;
 105                 }
 106
 107                 public override string ToString ()
 108                 {
 109                         if (Name != null)
 110                                 return Name;
 111                         if (ConverterType != null && TargetType != null)
 112                                 return String.Concat (ConverterType.Name, "(", TargetType.Name, ")");
 113                         else if (ConverterType != null)
 114                                 return ConverterType.Name;
 115                         else
 116                                 return TargetType.Name;
 117                 }
 118         }
 119 }