Re: Separate interface and implemenation problem..

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 5 Jun 2009 07:38:30 -0700 (PDT)
Message-ID:
<54e3b662-a423-4108-ad55-1c83dbaa7841@f16g2000vbf.googlegroups.com>
Mark Space wrote:

I like your syntax, although if an interface is only intended to be
used as a "static interface," it might be a good idea to explicitly
declare that fact.

// also not real code
public static interface MyRunnable {
  static void run(); // implicitly public
}


Steven Simpson wrote:

That first 'static' is already allowed, and has a meaning, though I


Only for nested types.

think it's redundant (right?). Nevertheless, I wouldn't like to claim =

a

new meaning for it at this stage.


JLS s. 8.5.2:

Member interfaces are always implicitly static. It is permitted but
not required for the declaration of a member interface to explicitly
list the static modifier.


Steven Simpson wrote:

But this marking seems unnecessary. Why does it matter that someone
implements MyRunnable non-statically? The user probably doesn't or
shouldn't (need to) care. If it matters to the implementation, let tha=

t

be it's [sic] own look-out.


If it were possible for a nested interface to be non-static, the
client code would care. Consider the case of member classes. Inner
classes and static nested classes differ with respect to the outer
'this' and related idioms.

--
Lew

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