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Re: Abstract Class versus an Interface, when no Members in Common

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On 11/3/2011 7:09 PM, KevinSimonson wrote:
> I have a method that needs to be able to return either of two very
> different types of data, in one case a class consisting of a two-
> dimensional array of<int>s accompanied by a single<byte>  value, and
> in the other case just a one-dimensional array of<int>s and that's
> all. So I created an abstract class called<SearchResult>  that has no
> members, not even any constructors, and made two classes extend
> <SearchResult>, the one class having the two-dimensional array and the
> <byte>  value, and the other having the one-dimensional array. Then I
> have my method return a value of<SearchResult>.
>
> My question is, in a situation like this where there are absolutely no
> variables or methods the two classes have in common, is it better to
> have an abstract class that both classes extend, or is it better to
> have an interface that both classes implement? Or is there any
> difference between the two approaches?

I don't like either approach. The calling code would need
to detect what type is actually returned and that would
most likely result in some very ugly code.

Two methods in the public API:

public Typ1 returnFoobarAsTyp1();
public Typ2 returnFoobarAsTyp2();

Arne

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Abstract Class versus an Interface, when no Members in Common KevinSimonson <kvnsmnsn@hotmail.com> - 2011-11-03 16:09 -0700
  Re: Abstract Class versus an Interface, when no Members in Common Arne Vajhøj <arne@vajhoej.dk> - 2011-11-03 19:32 -0400
  Re: Abstract Class versus an Interface, when no Members in Common markspace <-@.> - 2011-11-03 17:37 -0700
    Re: Abstract Class versus an Interface, when no Members in Common Lew <lewbloch@gmail.com> - 2011-11-03 18:10 -0700
      Re: Abstract Class versus an Interface, when no Members in Common markspace <-@.> - 2011-11-03 18:46 -0700
  Re: Abstract Class versus an Interface, when no Members in Common Roedy Green <see_website@mindprod.com.invalid> - 2011-11-03 22:06 -0700
  Re: Abstract Class versus an Interface, when no Members in Common Ian Pilcher <arequipeno@gmail.com> - 2011-11-04 00:06 -0500
  Re: Abstract Class versus an Interface, when no Members in Common Robert Klemme <shortcutter@googlemail.com> - 2011-11-04 17:57 +0100
  Re: Abstract Class versus an Interface, when no Members in Common Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-04 13:54 -0700
    Re: Abstract Class versus an Interface, when no Members in Common Wanja Gayk <brixomatic@yahoo.com> - 2011-11-08 23:15 +0100
      Re: Abstract Class versus an Interface, when no Members in Common Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-08 20:58 -0800
  Re: Abstract Class versus an Interface, when no Members in Common Roedy Green <see_website@mindprod.com.invalid> - 2011-11-04 15:17 -0700
  Re: Abstract Class versus an Interface, when no Members in Common Wanja Gayk <brixomatic@yahoo.com> - 2011-11-08 23:13 +0100

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