Re: Categories
Re: Categories
- Subject: Re: Categories
- From: Shawn Erickson <email@hidden>
- Date: Sat, 4 May 2002 16:58:23 -0700
On Saturday, May 4, 2002, at 03:44 PM, Ondra Cada wrote:
On Sunday, May 5, 2002, at 12:33 , Shawn Erickson wrote:
I haven't looked into NSMutableData myself but it is most likely part
of a class cluster. In a nut shell this means that when you use init
an NSMutableData object you get back a different type of object that
supports the same public messages that NSMutableData defines. So you
category is against NSMutableData not NSConcreteMutableData which
appears to be what you are really operating on when you attempt to
send the bzip2 message.
Also, NSConcreteMutableData is a subclass of NSMutableData, and thus it
inherits all NSMutableData methods, including those of categories.
There is absolutely no problem with clusters and categories; you need
to be cautious only when subclassing.
Yeah, that is true.
I wasn't sure if NSConcreteMutableData was a sub-class of NSMutableData
or not (it doesn't have to be). I figure it should be but what Owen
listed, assuming his category is correctly "attached"[1] to
NSMutableData, points to that fact it may not be.
Anyway, if it is a sub-class of NSMutableData then something is wrong
with your category.
Owen, how about a code snippet?
-Shawn
[1] What is the generally accepted term for the applying of a category
to a class?
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