#

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

# All rights reserved.

#

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

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

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

# (at your option) any later version.

#

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

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

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Lesser General Public License for more details.

# 

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

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

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

# the Threading module.

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

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

# WatchDogs can also be Started and Stopped.

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

import threading

class WatchDog(object):

    def __init__(self, interval, function):

        self.interval = interval

        self.function = function

        self.Watcher()

    def Watcher(self):

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

    def Start(self):

        self.timerThread.start()

    def Stop(self):

        self.timerThread.cancel()

    def Reset(self):

        self.Stop()

        self.Watcher()

        self.Start()