class/System/System.Diagnostics/Switch.cs

   1 //
   2 // System.Diagnostics.Switch.cs
   3 //
   4 // Comments from John R. Hicks <angryjohn69@nc.rr.com> original implementation
   5 // can be found at: /mcs/docs/apidocs/xml/en/System.Diagnostics
   6 //
   7 // Author:
   8 //      John R. Hicks  (angryjohn69@nc.rr.com)
   9 //      Jonathan Pryor (jonpryor@vt.edu)
  10 //
  11 // (C) 2001-2002
  12 //
  13
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System.Collections;
  36 using System.Collections.Specialized;
  37 #if NET_2_0 && CONFIGURATION_DEP
  38 using System.Configuration;
  39 #endif
  40
  41 namespace System.Diagnostics
  42 {
  43         public abstract class Switch
  44         {
  45                 private string name;
  46                 private string description;
  47                 private int switchSetting;
  48 #if NET_2_0
  49                 private string value;
  50                 private string defaultSwitchValue;
  51 #endif
  52                 // MS Behavior is that (quoting from MSDN for OnSwitchSettingChanged()):
  53                 //              "...It is invoked the first time a switch reads its value from the
  54                 //              configuration file..."
  55                 // The docs + testing implies two things:
  56                 //      1. The value of the switch is not read in from the constructor
  57                 //      2. The value is instead read in on the first time get_SwitchSetting is
  58                 //              invoked
  59                 // Assuming that OnSwitchSettingChanged() is invoked on a .config file
  60                 // read and on all changes
  61                 //
  62                 // Thus, we need to keep track of whether or not switchSetting has been
  63                 // initialized.  Using `switchSetting=-1' seems logical, but if someone
  64                 // actually wants to use -1 as a switch value that would cause problems.
  65                 private bool initialized;
  66
  67                 protected Switch(string displayName, string description)
  68                 {
  69                         this.name = displayName;
  70                         this.description = description;
  71                 }
  72
  73 #if NET_2_0
  74                 protected Switch(string displayName, string description, string defaultSwitchValue)
  75                         : this (displayName, description)
  76                 {
  77                         this.defaultSwitchValue = defaultSwitchValue;
  78                 }
  79 #endif
  80
  81                 public string Description {
  82                         get {return description;}
  83                 }
  84
  85                 public string DisplayName {
  86                         get {return name;}
  87                 }
  88
  89                 protected int SwitchSetting {
  90                         get {
  91                                 if (!initialized) {
  92                                         initialized = true;
  93                                         GetConfigFileSetting ();
  94                                         OnSwitchSettingChanged ();
  95                                 }
  96                                 return switchSetting;
  97                         }
  98                         set {
  99                                 if(switchSetting != value) {
 100                                         switchSetting = value;
 101                                         OnSwitchSettingChanged();
 102                                 }
 103                                 initialized = true;
 104                         }
 105                 }
 106
 107 #if NET_2_0
 108                 StringDictionary attributes = new StringDictionary ();
 109
 110 #if XML_DEP
 111                 [System.Xml.Serialization.XmlIgnore]
 112 #endif
 113                 public StringDictionary Attributes {
 114                         get { return attributes; }
 115                 }
 116
 117                 protected string Value {
 118                         get { return value; }
 119                         set {
 120                                 this.value = value;
 121 #if NET_2_0 && CONFIGURATION_DEP
 122                                 try {
 123                                         OnValueChanged ();
 124                                 } catch (Exception ex) {
 125                                         string msg = string.Format ("The config "
 126                                                 + "value for Switch '{0}' was "
 127                                                 + "invalid.", DisplayName);
 128
 129                                         throw new ConfigurationErrorsException (
 130                                                 msg, ex);
 131                                 }
 132 #else
 133                                 OnValueChanged ();
 134 #endif
 135                         }
 136                 }
 137
 138                 protected internal virtual string [] GetSupportedAttributes ()
 139                 {
 140                         return null;
 141                 }
 142
 143                 protected virtual void OnValueChanged ()
 144                 {
 145                 }
 146 #endif
 147
 148                 private void GetConfigFileSetting ()
 149                 {
 150                         IDictionary d = (IDictionary) DiagnosticsConfiguration.Settings ["switches"];
 151
 152                         // Load up the specified switch
 153                         if (d != null) {
 154                                 if (d.Contains (name)) {
 155 #if NET_2_0 && CONFIGURATION_DEP
 156                                         Value = d [name] as string;
 157 #else
 158                                         switchSetting = (int) d [name];
 159 #endif
 160                                         return;
 161                                 }
 162                         }
 163
 164 #if NET_2_0
 165                         if (defaultSwitchValue != null) {
 166                                 value = defaultSwitchValue;
 167                                 OnValueChanged ();
 168                         }
 169 #endif
 170                 }
 171
 172                 protected virtual void OnSwitchSettingChanged()
 173                 {
 174                         // Do nothing.  This is merely provided for derived classes to know when
 175                         // the value of SwitchSetting has changed.
 176                 }
 177         }
 178 }