1 #

     2 # Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 # All rights reserved.

     4 #

     5 # This program is free software: you can redistribute it and/or modify

     6 # it under the terms of the GNU Lesser General Public License as published by

     7 # the Free Software Foundation, either version 3 of the License, or

     8 # (at your option) any later version.

     9 #

    10 # This program is distributed in the hope that it will be useful,

    11 # but WITHOUT ANY WARRANTY; without even the implied warranty of

    12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    13 # GNU Lesser General Public License for more details.

    14 # 

    15 # You should have received a copy of the GNU Lesser General Public License

    16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

    17 

    18 # Implements a 'simple' watchdog built on top of the Timer class from

    19 # the Threading module.

    20 # After a specified interval a WatchDog will invoke a specified function.

    21 # At any point the WatchDog can be Reset, which means the countdown will start from scratch.

    22 # WatchDogs can also be Started and Stopped.

    23 # NB the WatchDog has no idea what the function it invokes will do.

    24 

    25 import threading

    26 

    27 class WatchDog(object):

    28     def __init__(self, interval, function):

    29         self.interval = interval

    30         self.function = function

    31         self.Watcher()

    32 

    33     def Watcher(self):

    34         self.timerThread = threading.Timer(self.interval, self.function)

    35 

    36     def Start(self):

    37         self.timerThread.start()

    38 

    39     def Stop(self):

    40         self.timerThread.cancel()

    41         

    42     def Reset(self):

    43         self.Stop()

    44         self.Watcher()

    45         self.Start()

    46