Re: is it possible to make superclass extend another class ?
krislioe@gmail.com wrote:
[Rearranged to avoid top posting confusion]
Patricia Shanahan wrote:
Andrew Thompson wrote:
krislioe@gmail.com wrote:
...
I have Class A as superclass.
I have Class B extend Class A
Then Class C extend Class B
Is it possible to make Class A Extend Class D ?
Sure. So long as D extends none of A, B or C.
BTW - are you sure this is the best design?
A lot of layers of 'extends' sometimes suggests 'no'.
(and those are silly class names - even for an abstraction)
Andrew T.
A couple of additional restrictions:
A must be a class you can change.
A's immediate superclass must also be a superclass of D, trivially true
if A is a direct subclass of Object.
I share Andrew's doubts about a design with that many layers.
Patricia
> Hi,
> Thank you for your response.
>
>> I share Andrew's doubts about a design with that many layers.
>
> As a rule of thumb, how many is indicating too many ?
>
I don't think there is any rule of thumb, but an increasing queasiness
as the number of inheritance levels increases. We have at least 5 levels
here (Object, D, A, B, C). Whether it makes sense to go that deep
depends on what the classes are about, but it is deep enough that I
would question it in my own code.
Patricia
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