Re: What is NSConcreteMutableData?

FROM : Guy English
DATE : Fri Nov 26 21:11:33 2004

NSData is a class cluster. See the developer documentation or Google
for a detailed explanation.

Basically initing an NSData class will actually give you a class more
tailored for what you'd like to use it for. It's an under the hood
optimization. All the classes in a class cluster will behave the same
way but their implementations will be optimized depending one the
usage they expect. You're looking at NSConceteMutableData which means
that you've got the actual class (hence the Concrete bit) that'll
manage mutable data. NSString is implemented in the same way and
you're likely to see a number of different classes under the hood of
an NSString.

Hope that helps a little,
Guy


On Fri, 26 Nov 2004 11:17:31 -0800, Frederick C. Lee
<<email_removed>> wrote:
> Greetings:
>        I'm deciphering a NSArrayController example that has a NSTextView
> field mapped to the key 'xnotes'.    The example saves/reads data just
> fine.    So I go into the debugger to explore the data array the is
> read/write from disk.  The following is what I've found for the
> 'xnotes' data key for the NSTextView:
>
> (gdb) po [[[toDos objectAtIndex:1] objectForKey:@"xnotes"] class]
> NSConcreteMutableData
> (gdb)
>
> I tried to read the data using [xnotes string] but didn't work.  The
> object didn't recognize the method.  So I asked the gdb to reveal the
> class to be: 'NSConcreteMutableData' which appears to be an oxymoron.
>
> Any ideas?
>
> Ric.
>
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