From: Robert Klemme <shortcutter@...>
Date: 2008-10-21T06:03:52+09:00
Subject: Re: timer

On 20.10.2008 22:28, angico wrote:
> [Note:  parts of this message were removed to make it a legal post.]
> 
> Hi, All.
> 
> Can anybody tell me how to implement kind of a timer in Ruby, similar to
> the following one from Java?
> 
> timer = new Timer( 200, handler ); // call handler each 200 milliseconds

Here's a simple one

#!/bin/env ruby

require 'monitor'

class Timer
   def initialize(interval, &handler)
     raise ArgumentError, "Illegal interval" if interval < 0
     extend MonitorMixin
     @run = true
     @th = Thread.new do
       t = Time.now
       while run?
	t += interval
	(sleep(t - Time.now) rescue nil) and
	  handler.call rescue nil
       end
     end
   end

   def stop
     synchronize do
       @run = false
     end
     @th.join
   end

   private

   def run?
     synchronize do
       @run
     end
   end
end

t = Timer.new(1) do
   puts "tick #{Time.now.to_f}"
   # random sleep to show slot stability
   sleep((5 + rand(10))/10.0)
end

sleep 10
t.stop