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Chris Uppal <> wrote:
: Dale King wrote:

:> > That's a generic problem with using Java interfaces - if you
:> > implement them the world and his wife gets to use them - which
:> > is not necessarily what the programmer wants.
:>
:> Not strictly true. While all members of the interface are public, the
:> interface itself may not be.

: Agreed, and if that's not a clear indication that the spec is
: misconceived then I don't know what would be.

: IMO the condition *should* be that the members required by an interface
: must be at least as accessible as the interface itself.

That wouldn't help with the Cloneable problem. There
we want the inteface to be public - so anyone can use it.

However we don't want to place the burden of making their clone
method public on all the implementors of Cloneable.

So that seems like a case where the member(s) of the interface
ought to be /less/ accessible than the interface itself.
--
__________
|im |yler http://timtyler.org/

Tim Tyler wrote:

> > IMO the condition *should* be that the members required by an
> > interface must be at least as accessible as the interface itself.
>
> That wouldn't help with the Cloneable problem. There
> we want the inteface to be public - so anyone can use it.

Agreed. I was talking about the Java interfaces in general rather than this
specific case.

> However we don't want to place the burden of making their clone
> method public on all the implementors of Cloneable.

I don't see why not. Few objects *shouldn't* be cloned, so it seems to me that
the facility should be "opt out" not "opt in". E.g. Object.clone() could be
public and throw a CloneNotSupportedException if the class in question
didn't support/allow cloning.

-- chris

Chris Uppal <> wrote:
: Tim Tyler wrote:

:> However we don't want to place the burden of making their clone
:> method public on all the implementors of Cloneable.

: I don't see why not. [...]

That is the reason that was given as to why Java's designers didn't
put the clone method in the Cloneable interface:

``Putting the clone() method in the interface would force public
accessibility to that method, which is not an intended effect
of marking a class as Cloneable.''

I think that is a reasonable point - you might not want
the clone method exposed in your public API - you
might want to restrict who can make copies your objects.
--
__________
|im |yler http://timtyler.org/

In article <>, Tim Tyler <> wrote:
>
>I think that is a reasonable point - you might not want
>the clone method exposed in your public API - you
>might want to restrict who can make copies your objects.

While that is true, I still feel they could have had a PublicClonable
interface for those that _do_ want to expose cloning. This would make
sense for a large number of classes, and would enable people to make
copies of arbitrary clonable objects without serialization or
reflection hacks.

Cheers
Bent D
--
Bent Dalager - - http://www.pvv.org/~bcd
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