stoop ed-dual interface

Stéphane Ducasse 1

Stéphane Ducassestephane.ducasse@inria.frhttp://stephane.ducasse.free.fr/

Design Points - Dual Interfaces

Stéphane Ducasse --- 2005

S.Ducasse 2

Clients?• Clients• Subclasses

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What are the consequences?

A { private x ;void foo(){ ... x ...}}

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What can I do as a subclass?

I cannot access xI cannot replace xI cannot extend!

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The idiom is

Fields are private AND you provide protected accessors

Fields are protected

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Benefits

Your clients cannot access your fieldsBut your subclasses are empowered

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Two users

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Two Users

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Clients

A class has always two clients:its clients and its extenders

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