Hi Radu

2014-08-23 17:43 GMT+02:00 Radu Cotescu <[email protected]>:

> Hi Carsten,
>
> You are right, the BVP with the highest service.ranking is called last. But
> shouldn't it be called first, in order to be consistent with the OSGi way
> of obtaining a reference? To me it's counter-intuitive to set the
> service.ranking value to a negative value if I want my BVP to be called
> before a another BVP with no service.ranking property set explicitly.
>
> In the end I think the answer revolves around the way we think a BVP is
> more powerful: if it's called last in the queue or first.
>
> Right, its more powerful if it runs last, as it can overwrite/change
values provided by earlier BVPs

Carsten


> Regards,
> Radu
>
>
> On Fri, Aug 22, 2014 at 6:44 PM, Carsten Ziegeler <[email protected]>
> wrote:
>
> > Hi Radu,
> >
> > I think the current order is giving the service with the highest ordering
> > the final call. If two providers provide a value for the same key, the
> one
> > with the highest wins as it is called last. So I think this matches the
> > other usages of service ranking.
> >
> > Regards
> > Carsten
> >
> >
> > 2014-08-22 17:17 GMT+02:00 Radu Cotescu <[email protected]>:
> >
> > > Hi,
> > >
> > > In SLING-3320 [0] we introduced some ordering in the BVPs maps, such
> that
> > > BVPs are called using the natural ordering of their ServiceReferences,
> > > which is based on the service.ranking value: the higher the
> > service.ranking
> > > is, the later in the call chain will a BVP be called to add its
> bindings.
> > >
> > > Given that in the OSGi world the service.ranking is used to determine
> > which
> > > implementation is returned for a certain service, the rule of thumb
> being
> > > that the higher the service.ranking is the most likely that
> > implementation
> > > will be provided, should't we actually reverse the sort order of the
> > BVPs?
> > >
> > > In theory this might introduce some subtle bugs in clients' code, but
> no
> > > one complained when we introduced the ordering in the first place.
> > >
> > > WDYT?
> > >
> > > Cheers,
> > > Radu
> > >
> > > [0] - https://issues.apache.org/jira/browse/SLING-3320
> > >
> >
> >
> >
> > --
> > Carsten Ziegeler
> > Adobe Research Switzerland
> > [email protected]
> >
>



-- 
Carsten Ziegeler
Adobe Research Switzerland
[email protected]

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