Re: light weight types

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 11 Oct 2009 05:57:31 -0700

Message-ID:

<CvWdnU2oJ-ikS0zXnZ2dnUVZ_gFi4p2d@earthlink.com>

Steven Simpson wrote:

Patricia Shanahan wrote:

Peter Duniho wrote:

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>()

If you could, wouldn't it alternatively be possible to get the compiler
to regard an unadorned Map as Map<Object,Object>, rather than warning
about it?

I assume that alternative was considered, and rejected. If they had kept
the non-generic interfaces and provided new ones for generics, it would
have been a good choice. Generally, when I change one of my classes to
use generics, I intend to make the corresponding changes in all uses,
and want to be warned of any failure to do so.

Patricia