Re: Keeping NSTimeInterval updated with current time
Re: Keeping NSTimeInterval updated with current time
- Subject: Re: Keeping NSTimeInterval updated with current time
- From: Graham Cox <email@hidden>
- Date: Tue, 3 Nov 2009 12:10:28 +1100
On 03/11/2009, at 10:10 AM, PCWiz wrote:
What I want to do is around every 5 minutes, update the timeInterval
to be consistent with the current time. The problem is that I need
to do this update for a large number of instances of the object. One
way I could think to do this would be to enumerate through the array
containing the objects every 5 minutes and just set the timeInterval
property. But is there a more efficient way to do this?
The simple answer is to use NSArray's -
makeObjectsPerformSelector:withObject: to rapidly pass a parameter to
the same method of a collection of objects.
But, maybe a better answer is to consider why you are doing this. If
you have a bunch of objects that need to know the current time (to the
nearest five minutes) why not just have them grab that time at the
moment when they need to know it. If they are just sitting there they
don't need to be updated - only when one of them is called into play
and needs to do some calculation with the time does that time need to
be updated, at which point it should grab it for itself. If rounding
off the time to the last 5-minute interval is a problem (e.g. every
object must have the exact same value), you could do that every 5
minutes and cache the result somewhere where all the other objects can
grab it as needed.
This type of lazy evaluation is by far the better way to code a
problem like this - do the minimum work necessary, and never push
state to objects that don't need it *NOW*.
--Graham
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