Re: KVO and the observeValueForKeyPath bottleneck

FROM : Scott Anguish
DATE : Fri Jul 21 23:01:12 2006

On Jul 21, 2006, at 11:46 AM, George Orthwein wrote:

> On Jul 21, 2006, at 4:11 AM, Scott Anguish wrote:

>> in my original reply, when I said controller I meant specifically 
>> NS*Controller

>
> So the only recommended application of "one way" bindings would be 
> between an NS*Controller and an NSView subclass, or also possibly 
> between an NS*Controller and a model class?


   I'm not sure what you mean by "one-way".  We have what are called 
"read-only" bindings (where the attribute that you've bound to an 
object will not cause any changes in the UI to be propagated back to 
the object).

>
> That's good to know and I don't think it's come up in past 
> discussions, or at least stated as plainly. The lack of any mention 
> of "one way" bindings is what I was referring to in the docs... 
> though it now seems that there is only a specific application for 
> them anyway. (Well, NS*Controller and a custom view should be 
> pretty common....)
>
> It's a good point for this discussion though, since we seemed to be 
> settling in on:
>

>> True. I guess if you want to avoid the KVO "bottleneck" you can 
>> just use "one way" bindings instead!


   just to ensure clarity. this is not my position and I didn't write 
that.

>
> A general statement like doesn't work, since KVO can be used in 
> situations where "one way" bindings aren't recommended (Matt's 
> position notwithstanding :) ).



   Regardless of matt's position, it isn't recommended.