On Mon, 21 Jan 2008 13:24:49 -0500 "John Siracusa" <[EMAIL PROTECTED]> wrote:
JS> On Jan 21, 2008 8:34 AM, Ted Zlatanov <[EMAIL PROTECTED]> wrote: >> I have some existing RDBO classes, all inheriting from a common >> BaseObject parent. If I want some of them to be selectively cached, >> currently I have to create a BaseObject::Cached that inherits from >> RDBO::Cached (I do this with a copy+edit, see below), and then each of >> my classes can inherit from the cached variation. The issue is that any >> functionality in BaseObject will not be in my cached variation unless I >> do a copy+edit. I considered making BaseObject::Cached inherit from >> BaseObject and RDBO::Cached but that seems like asking for trouble. JS> I do this, and so far the world has not ended :) JS> package MyCorp::DB::Object::Cached; JS> use base 'Rose::DB::Object::Cached'; JS> ... JS> package MyProj::DB::Object; JS> use base 'MyCorp::DB::Object'; JS> ... JS> package MyProj::DB::Object::Cached; JS> use base qw(MyCorp::DB::Object::Cached MyProj::DB::Object); JS> Obviously this doesn't allow methods in MyProj::DB::Object::Cached to JS> override methods in MyCorp::DB::Object::Cached, but every arrangement JS> has some tradeoff, thanks to Perl's left-most depth-first dispatch. JS> (To get a better arrangement, you can always use Class::C3 or JS> something...) Ideally I should say package My::DB::Thing::Cached; use base qw/Rose::DB::Object::Cached My::DB::BaseObject/; Otherwise I have to maintain two classes no matter what. With this approach, init_db() will be the default, which is not good. >> Is there an easier way? If a mixin could do it that would be great. I >> didn't see a way in the docs. If not, maybe there's a better approach >> I'm missing. JS> When I need a mix-in, I just "make one" by manually importing methods JS> as needed. Writing a helper for this isn't too hard. Look around JS> line 560 of this file for an example: JS> http://search.cpan.org/src/JSIRACUSA/Rose-HTML-Objects-0.552/lib/Rose/HTML/Object.pm That's a pretty nasty hack. Really, I think this should be a standard mixin, instead of forcing users to derive from a different class when all that's changing is one small piece of the overall behavior. What methods are different in RDBO::Cached (I can look it up myself, but let me know if there are any gotchas)? I'll write the mixin code myself and you can put it in RDBO::Helpers or I'll make a new CPAN module for it. JS> IMO, all such things are fair in super-wide-usage base classes. Do JS> the complicated stuff in a very few well-defined places and reap the JS> benefits broadly. Agreed. I'd like that place to be RDBO::Helpers, not My::DB::BaseObject :) Ted ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
