mcs/class/System/System.Timers/Timer.cs

   1 //
   2 // System.Timers.Timer
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc (http://www.ximian.com)
   8 //
   9 // The docs talk about server timers and such...
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System;
  33 using System.ComponentModel;
  34 using System.Threading;
  35
  36 namespace System.Timers
  37 {
  38         [DefaultEventAttribute("Elapsed")]
  39         [DefaultProperty("Interval")]
  40         public class Timer : Component, ISupportInitialize
  41         {
  42                 bool autoReset;
  43                 bool enabled;
  44                 double interval;
  45                 ISynchronizeInvoke so;
  46                 ManualResetEvent wait;
  47
  48                 [Category("Behavior")]
  49                 [TimersDescription("Occurs when the Interval has elapsed.")]
  50                 public event ElapsedEventHandler Elapsed;
  51
  52                 public Timer () : this (100)
  53                 {
  54                 }
  55
  56                 public Timer (double interval)
  57                 {
  58                         autoReset = true;
  59                         enabled = false;
  60                         Interval = interval;
  61                         so = null;
  62                         wait = null;
  63                 }
  64
  65
  66                 [Category("Behavior")]
  67                 [DefaultValue(true)]
  68                 [TimersDescription("Indicates whether the timer will be restarted when it is enabled.")]
  69                 public bool AutoReset
  70                 {
  71                         get { return autoReset; }
  72                         set { autoReset = value; }
  73                 }
  74
  75                 [Category("Behavior")]
  76                 [DefaultValue(false)]
  77                 [TimersDescription("Indicates whether the timer is enabled to fire events at a defined interval.")]
  78                 public bool Enabled
  79                 {
  80                         get { return enabled; }
  81                         set {
  82                                 if (enabled == value)
  83                                         return;
  84
  85                                 enabled = value;
  86                                 if (value) {
  87                                         Thread t = new Thread (new ThreadStart (StartTimer));
  88                                         t.IsBackground = true;
  89                                         t.Start ();
  90                                 } else {
  91                                         StopTimer ();
  92                                 }
  93                         }
  94                 }
  95
  96                 [Category("Behavior")]
  97                 [DefaultValue(100)]
  98                 [RecommendedAsConfigurable(true)]
  99                 [TimersDescription( "The number of milliseconds between timer events.")]
 100                 public double Interval
 101                 {
 102                         get { return interval; }
 103                         set {
 104                                 // The doc says 'less than 0', but 0 also throws the exception
 105                                 if (value <= 0)
 106                                         throw new ArgumentException ("Invalid value: " + interval, "interval");
 107
 108                                 interval = value;
 109                         }
 110                 }
 111
 112                 public override ISite Site
 113                 {
 114                         get { return base.Site; }
 115                         set { base.Site = value; }
 116                 }
 117
 118                 [DefaultValue(null)]
 119                 [TimersDescriptionAttribute("The object used to marshal the event handler calls issued " +
 120                                             "when an interval has elapsed.")]
 121                 public ISynchronizeInvoke SynchronizingObject
 122                 {
 123                         get { return so; }
 124                         set { so = value; }
 125                 }
 126
 127                 public void BeginInit ()
 128                 {
 129                         // Nothing to do
 130                 }
 131
 132                 public void Close ()
 133                 {
 134                         StopTimer ();
 135                 }
 136
 137                 public void EndInit ()
 138                 {
 139                         // Nothing to do
 140                 }
 141
 142                 public void Start ()
 143                 {
 144                         Enabled = true;
 145                 }
 146
 147                 public void Stop ()
 148                 {
 149                         Enabled = false;
 150                 }
 151
 152                 protected override void Dispose (bool disposing)
 153                 {
 154                         Close ();
 155                         base.Dispose (disposing);
 156                 }
 157
 158                 static void Callback (object state)
 159                 {
 160                         Timer timer = (Timer) state;
 161                         if (timer.Elapsed == null)
 162                                 return;
 163
 164                         ElapsedEventArgs arg = new ElapsedEventArgs (DateTime.Now);
 165
 166                         if (timer.so != null && timer.so.InvokeRequired) {
 167                                 timer.so.BeginInvoke (timer.Elapsed, new object [2] {timer, arg});
 168                         } else {
 169                                 timer.Elapsed (timer, arg);
 170                         }
 171                 }
 172
 173                 void StartTimer ()
 174                 {
 175                         wait = new ManualResetEvent (false);
 176
 177                         WaitCallback wc = new WaitCallback (Callback);
 178                         while (enabled && wait.WaitOne ((int) interval, false) == false) {
 179                                 if (autoReset == false)
 180                                         enabled = false;
 181
 182                                 ThreadPool.QueueUserWorkItem (wc, this);
 183                         }
 184
 185                         wc = null;
 186                         ((IDisposable) wait).Dispose ();
 187                         wait = null;
 188                 }
 189
 190                 void StopTimer ()
 191                 {
 192                         if (wait != null)
 193                                 wait.Set ();
 194                 }
 195         }
 196 }
 197