Differing implementations for a function in two interfaces

[BCS]

Chris Nicholson-Sauls wrote:
> Ryan Steen wrote:
> 
>> In article <e1vlnb$226i$1 at digitaldaemon.com>, Lionello Lunesu says...
>>
>>> IA might be an interface for the output/GUI and IB for the input.
>>
>>
>>
>> Yes, but what might cause the need to have the implementation in one 
>> class?
>>
>> And if there is really a need what hinders a virtual split of that 
>> implenting
>> class?
>>
>> IA --> CA <-- C --> CB <-- IB
>>
>> where --> and <-- denote inheretance?
> 
> Here you lose encapsulation, wherein you are basically having to create 
> a C, then ask it for its CA and later for its CB, and the CA/CB classes 
> (inner classes, maybe?) have to know their parent object and ask it for 
> the real data and behaviors.  Ew, ew, ew. 

I fully agree.

>(Although at least inner 
> classes won't need the parent pointer,

yes but only because its already hidden in there by the compiler

 > once we settle on some kind of
> 'parent' or 'outer' keyword.)
> 
> -- Chris Nicholson-Sauls