C#

    /// <summary>
    /// A class that allows an externally accessible hearbeat to be set for an application 
    /// </summary>
    public static class Heartbeat  
    {

        private static HeartbeatListenerCollection _listeners = new HeartbeatListenerCollection();

        /// <summary>
        /// Sends a heartbeat to any heartbeat monitors
        /// to indicate that the application is running
        /// </summary>
        public static void Beat()
        {
            // make each heartbeat listener beat 
            foreach (HeartbeatMonitorBase  _listener in Listeners)
            {
                _listener.Beat();
            }
        }


        /// <summary>
        /// Starts the heartbeat with a default frequency
        /// </summary>
        static Heartbeat()
        {
            // Fire up a thread to invoke hearbeat events 
            // perdiodically...
            TimerCallback timerDelegate =
            new TimerCallback(Heartbeat.Beat);

            AutoResetEvent autoEvent = new AutoResetEvent(false);

            System.Threading.Timer heartbeatTimer =
                new System.Threading.Timer(timerDelegate, autoEvent, 0,1000);
            

        }


        /// <summary>
        /// The listeners attached to the heartbeat
        /// </summary>
        /// <remarks >
        /// These should not be triggered directly but rather the 
        /// Heartbeat.Beat() method should be called
        /// </remarks>
        public  static HeartbeatListenerCollection Listeners
        {
            get { return Heartbeat._listeners; }
        }
    }
}