launchpad-dev team mailing list archive

["Francis J. Lacoste" <francis.lacoste@xxxxxxxxxxxxx>]

On December 2, 2009, Gary Poster wrote:
> On Dec 2, 2009, at 12:47 PM, Francis J. Lacoste wrote:
> > On December 2, 2009, Gary Poster wrote:
> >> On Dec 2, 2009, at 11:41 AM, Muharem Hrnjadovic wrote:
> >>> Gary Poster wrote:
> >>>> On Dec 2, 2009, at 10:41 AM, Muharem Hrnjadovic wrote:
> >>>>> Quick question:
> >>>>>
> >>>>> do we use the zope class registry anywhere?
> >>>>
> >>>> I doubt it.
> >>>>
> >>>>> Is it safe to use within
> >>>>> Launchpad?
> >>>>
> >>>> I'd prefer to use utility registration if that can work with your use
> >>>> case.
> >>>
> >>> Sorry for not being precise enough. In my particular case a number of
> >>> classes would implement the interface in question (IBuildFarmJob).
> >>>
> >>> I understood the utility registration mechanism requires that there is
> >>> exactly one class that implements a particular interface in which case
> >>> I could not use it for the interface/purpose at hand.
> >>
> >> The class registry you showed had keys and values.
> >>
> >> You can register different utilities for the same interface by providing
> >> a different name for each one (I think of this as a namespace).
> >>
> >> You can then get all of the utilities for that interface with
> >
> > getUtilitiesFor.  From docs:
> >>>>> sorted(components.getUtilitiesFor(tests.I2))
> >>
> >> [(u'', U12(2)), (u'three', U12(3))]
> >>
> >> In that example, ``components`` could be obtained as follows:
> >>
> >> from zope.component import getSiteManager
> >> components = getSiteManager()
> >
> > Another possibility is to use subscriptions. You can register components
> > for the IBuildFarmJob interface and get all the registered subscribers.
> 
> Absolutely.
> 
> FWIW, I don't like subscription adapters because their functionality can be
>  essentially duplicated in the way I described, with named utilities.  I'm
>  trying to reduce the number of things to learn about in Zope's Component
>  Architecture in zope-dev.  So I don't recommend them...but that's just me.
>  :-)

Then what Gary says :-) 


-- 
Francis J. Lacoste
francis.lacoste@xxxxxxxxxxxxx

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