Pause/Resume functions for timer

Question

I need to use a timer which can be paused and resumed. As far as I know there is only one timer in Python which is contained in the threading package, but I cannot pause or resume it, only cancel it.

This is a standard code to use the timer in Python:

from threading import Timer
import time

def timeout():
     print "Game over"

t = Timer(20 * 60, timeout)
t.start()

So what should I do to realize pause/resume functions with this timer?

Answer 1

import threading, time

class ResumableTimer:
    def __init__(self, timeout, callback):
        self.timeout = timeout
        self.callback = callback
        self.timer = threading.Timer(timeout, callback)
        self.startTime = time.time()

    def start(self):
        self.timer.start()

    def pause(self):
        self.timer.cancel()
        self.pauseTime = time.time()

    def resume(self):
        self.timer = threading.Timer(
            self.timeout - (self.pauseTime - self.startTime),
            self.callback)

        self.timer.start()

Your homework:

• Inheritance?
• Exceptions? Checks?
• Something better than a resumable timer