Re: light weight types

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 10 Oct 2009 23:17:40 -0700

Message-ID:

<47GdneDAtpYe5UzXnZ2dnUVZ_jmdnZ2d@earthlink.com>

Peter Duniho wrote:

Mike Schilling wrote:

Peter Duniho wrote:

Though, .NET illustrates that an alternative approach would have been
to simply create a new, parallel group of classes supporting
generics, rather than to insist that the old classes be reusable via
generics.

It's technically feasible, sure, but given the amount of existing Java
code when 1.5 was introduced, imagine the dumbfoundment with which a
new and incompatible set of, e.g. collections classes (and, far worse,
collection interfaces) would have been greeted.

....

I think in the short run, the big win was not having to reimplement all
those classes. And to be sure, I've no doubt it saved someone a fair
amount of time. But that cost is, in the long run, relatively small,
and the consequences are significant.

Would it have taken much time? Couldn't one do something like:

public interface Map extends GMap<Object,Object>()

public class HashMap extends GHashMap<Object,Object>()

etc.

The generic version would have needed a name or package change, as well
as the changes that had to be done anyway. The compatibility class would
be the generic class bound to Object.

Patricia