Re: Re: KVO and the observeValueForKeyPath bottleneck

FROM : Michael Ash
DATE : Mon Jul 17 20:11:41 2006

On 7/17/06, Matt Neuburg <<email_removed>> wrote:
> On or about 7/17/06 7:57 AM, thus spake "Jakob Olesen" <<email_removed>>:
>
> > Seriously, is there any reason for checking respondsToSelector?
> > Wouldn't it be better to get an exception (or crash) if you mistype
> > the selector or somebody else registers you as an observer?
>
> No. That's not how notification (or, for that matter, delegation) behaves.
> Both those behaviors are considered perfectly acceptable. m.


Delegation and notifications actually behave completely oppositely in
this respect. If you fail to implement a delegate method then nothing
happens except the object uses the default behavior. If you fail to
implement a notification method (one you explicitly signed up for, not
one that you get "for free" as part of being a delegate) then you get
a nice runtime exception when the notification is sent.

Since this case is much more analogous to notifications than
delegation, getting the exception is probably the right approach.

Mike