«

Hey guys,

I've been studying Ruby for some weeks now but when it comes to
threads, I know that I am totally unskilled.

I am trying to build a class which is able to keep updating itself every
X seconds after being initialized. In general terms it would work like
this:

----
class Threading_Test
attr_accessor :i
def initialize
@i = 0
@j = 0
neverstop = false

t1 = Thread.new do
while neverstop == false do
sleep 0.1 #here's the the problem.
@i = @i + 1
end
end

t1.run

puts "I am ready and I keep updating myself. Or not..."
end
end
----


The problem occurs when I try to add this "sleep 0.1" into the thread
block. The thread only seems to become active when I ask for the @i
value.

I know that there might be other ways to implement that, but i think
that it would fit my code better that setting up a Cron task to do so.

Thank you all for the help.
--
Posted via http://www.ruby-forum.com/.

Alex Zunega wrote:
> Hey guys,
>
> I've been studying Ruby for some weeks now but when it comes to
> threads, I know that I am totally unskilled.
>
> I am trying to build a class which is able to keep updating itself every
> X seconds after being initialized. In general terms it would work like
> this:
>
> ----
> class Threading_Test
> attr_accessor :i
> def initialize
> @i = 0
> @j = 0
> neverstop = false
>
> t1 = Thread.new do
> while neverstop == false do
> sleep 0.1 #here's the the problem.
> @i = @i + 1
> end
> end
>
> t1.run
>
> puts "I am ready and I keep updating myself. Or not..."
> end
> end
> ----
>
>
> The problem occurs when I try to add this "sleep 0.1" into the thread
> block. The thread only seems to become active when I ask for the @i
> value.
>

I'm not sure what you mean. Try this:

class Updater
attr_accessor :i

def initialize
@i = 0

Thread.new do
loop do
sleep(1)
@i += 1
puts "....#{@i}"
end
end

end

end


upd = Updater.new

5.times do
sleep(2)
puts upd.i
end

Here is my output:
....1
1
....2
....3
3
....4
....5
5
....6
....7
7
....8
....9
9

--
Posted via http://www.ruby-forum.com/.

Alex Zunega wrote:
> Hey guys,
>
> I've been studying Ruby for some weeks now but when it comes to
> threads, I know that I am totally unskilled.
>

Also, you should realize that the @i in the class and the @i in the
thread are the same variable.
Therefore, things like this can happen:

class Updater
attr_accessor :i

def initialize
@i = 0

Thread.new do
loop do
sleep(0.3)
@i += 1
puts "....#{@i}"
end
end

end

end


upd = Updater.new

3.times do
sleep(2)
puts upd.i

upd.i = 0 #<-----******
end

--output:--
....1
....2
....3
....4
....5
....6
6
....1
....2
....3
....4
....5
....6
....7
7
....1
....2
....3
....4
....5
....6
6


--
Posted via http://www.ruby-forum.com/.

7stud -- wrote:
> Alex Zunega wrote:
>> Hey guys,
>>
>> I've been studying Ruby for some weeks now but when it comes to
>> threads, I know that I am totally unskilled.
>>
>
> Also, you should realize that the @i in the class and the @i in the
> thread are the same variable.
> Therefore, things like this can happen:
>
> class Updater
> attr_accessor :i
>
> def initialize
> @i = 0
>
> Thread.new do
> loop do
> sleep(0.3)
> @i += 1
> puts "....#{@i}"
> end
> end
>
> end
>
> end
>
>
> upd = Updater.new
>
> 3.times do
> sleep(2)
> puts upd.i
>
> upd.i = 0 #<-----******
> end
>
> --output:--
> ....1
> ....2
> ....3
> ....4
> ....5
> ....6
> 6
> ....1
> ....2
> ....3
> ....4
> ....5
> ....6
> ....7
> 7
> ....1
> ....2
> ....3
> ....4
> ....5
> ....6
> 6


Hey 7stud,

Thanks for the very prompt answer. I couldn't make myself clear and I'll
try harder this time...

I've just removed two lines from the code you genially sent me. Removing
these two lines I got the behavior I would like to have. See the code
and results below:

>> class Updater
>> attr_accessor :i
>>
?> def initialize
>> @i = 0
>>
?> Thread.new do
?> loop do
?>
?> @i += 1
>>
?> end
>> end
>>
?> end
>>
?> end
=> nil
>> x.i
=> 213336
>> x.i
=> 237848
>>

I just want something to time these iteration (one per second, for
example), and everytime that I insert some "sleep" method, the Updater
would "sum 1" to @i only when I try to access @i attribute.

What I expect, in other words, is to have an @i very close to the number
of seconds of the object life, just to prove that it works...


--
Posted via http://www.ruby-forum.com/.

Alex Zunega wrote:
>
> I just want something to time these iteration (one per second, for
> example), and everytime that I insert some "sleep" method, the Updater
> would "sum 1" to @i only when I try to access @i attribute.
>
> What I expect, in other words, is to have an @i very close to the number
> of seconds of the object life, just to prove that it works...

You aren't making any sense. On the one hand, you say that you want @i
to tell you the number of seconds the object has been "alive". On the
other hand, you say you only want to add 1 to @i when you try to access
@i. Which is it?


--
Posted via http://www.ruby-forum.com/.

7stud -- wrote:
> Alex Zunega wrote:
>>
>> I just want something to time these iteration (one per second, for
>> example), and everytime that I insert some "sleep" method, the Updater
>> would "sum 1" to @i only when I try to access @i attribute.
>>
>> What I expect, in other words, is to have an @i very close to the number
>> of seconds of the object life, just to prove that it works...
>
> You aren't making any sense. On the one hand, you say that you want @i
> to tell you the number of seconds the object has been "alive". On the
> other hand, you say you only want to add 1 to @i when you try to access
> @i. Which is it?

Actually, you're right, I was not clear, but I meant the second one.
After initialized, 10 seconds later, when retrieving @i value I would
like to see @i as 10, meaning that for 10 times it updated itself.
--
Posted via http://www.ruby-forum.com/.

I give up.
--
Posted via http://www.ruby-forum.com/.

7stud's original Updater class seems to meet the requirements.=A0 Are
you trying to write a class that will perform some work and then sleep
1.0 seconds and keep a count of the number of iterations it performed?
Or are you trying to right a class that will perform some work
exactly once per second?=A0 In the first case, your work will not
generally fire once a second because the work itself will take a non
zero amount of time.=A0 The second case is trickier ... maybe this would
work:

class PeriodicWorker
=A0 def initialize(period =3D 1.0)
=A0=A0=A0 @period =3D period
=A0 end

=A0 def run
=A0=A0=A0 start =3D Time.now.to_f
=A0=A0=A0 while true
=A0=A0=A0=A0=A0 yield
=A0=A0=A0=A0=A0 sleep_time =3D (start + @period) - Time.now.to_f
=A0=A0=A0=A0=A0 sleep(sleep_time) rescue nil # Punt if the worker took long=
er
than @period seconds to run
=A0=A0=A0=A0=A0 start +=3D @period
=A0=A0=A0 end
=A0 end
end

worker =3D PeriodicWorker.new

worker.run do
=A0puts "Time: #{Time.now.to_f}"
=A0sleep 0.22
=A0puts "Finished my work: #{Time.now.to_f}"
end


The only issue with this class is if the work takes longer than the
period, you are creating a spinloop that will suck up 100% of your
CPU.

-Doug Seifert