Re: what is the RIGHT THING to make a constructor of a subclass, using super()

Daniel Pitts <>
Mon, 28 Jul 2008 14:29:18 -0700
Mark_Galeck wrote:

Hello, what is the RIGHT THING, to write a constructor for a
subclass, that needs to compute arguments to the super() call?? How
do experienced and elegant Java programmers do it?

The meaning of a subclass is that it adds more to its superclass, so
for example, it can have a constructor arguments types that the
superclass does not have. With these arguments, I have to first
compute the arguments to the superclass constructor (using the
arguments supplied to the subclass), and it is hard to do all these
computations inside the call to super(). I can do it, but it is, as
one of my first programming professors once put "your code is ugly and
miserable". Since Java is a well-designed language, I must be doing
the WRONG THING, what is it, how do I do it the right way??

Thank you for your insights


Perhaps the problem is that you're trying to use inheritance of
implementation when you should be using composition or some other design

If you really want your "subclass" to have the same interface (and be
polymorphic), then you should consider creating an interface for it.

That way, the "super(...)" call actually becomes a "new Delegate(...)"
call instead, and can occur anywhere in the constructor.

Hope this helps,

Daniel Pitts' Tech Blog: <>

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