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Bindings: Where/when should dependent keys be registered? (when class with dependent keys is subclassed)



The example at:

<http://developer.apple.com/documentation/Cocoa/Conceptual/ CurrencyConverterBindings/03creatingmodel/chapter_3_section_1.html>

registers them in the +initialize method.

Is this recommended practice?

The reason that I ask is that

<http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC/ LanguageOverview/chapter_3_section_4.html#//apple_ref/doc/uid/ 20001424-87244>

says:

The runtime system sends an initialize message to every class object
before the class receives any other messages and after its superclass
has received the initialize message. [...]


Because of inheritance, an initialize message sent to a class that
doesn’t implement the initialize method is forwarded to the superclass,
even though the superclass has already received the initialize message.
For example, assume class A implements the initialize method, and class
[...]


    To avoid performing initialization logic more than once [...]

But more importantly:

Note: Remember that the runtime system sends initialize to each class
individually. Therefore, in a class’s implementation of the initialize
method, you must not send the initialize message to its superclass.


This means if I have:

class Person
    name (key)
    uppercaseName (dependent key)

class Employee
    department

and I do as the example suggests, that dependent keys won't be registered for Employee if it implements +initialize, and per the runtime docs, doesn't call send initialize to the super class.

What is the recommended/clean solution to this problem?

Thanks,
Jim _______________________________________________
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