suplib/src/IOWatchDog.i3


 Copyright 1996-2003 John D. Polstra.
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 *      This product includes software developed by John D. Polstra.
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 * $Id: IOWatchDog.i3.html,v 1.2 2009-06-26 16:35:46 wagner Exp $ 

INTERFACE IOWatchDog;

IMPORT Rd, Time, Wr;

TYPE
  T <: Public;

  Public = Private OBJECT METHODS
    init(timeout: Time.T;
	 pollInterval: Time.T := 60.0d0): T;
    alert();
  END;

  Private <: ROOT;
The init method primes the watchdog timer to call its alert method after the interval timeout expires. pollInterval is the number of seconds between polls conducted by the watchdog timer.

The default alert method calls Thread.Alert on the thread that initialized the watchdog timer.

PROCEDURE AddRd(wd: T;
                rd: Rd.T);
Adds the given reader to the set monitored by the watchdog timer.

PROCEDURE AddWr(wd: T;
                wr: Wr.T);
Adds the given writer to the set monitored by the watchdog timer.
 Both readers and writers are removed automatically when it is discovered
   that they are closed. 

PROCEDURE Cancel(wd: T);
Cancels the watchdog timer.

PROCEDURE Expired(wd: T): BOOLEAN;
Returns TRUE if the watchdog timer has expired and alerted the target thread.

END IOWatchDog.