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From BJ Hargrave <hargr...@us.ibm.com>
Subject Re: ServiceTracker
Date Tue, 22 May 2007 19:24:29 GMT
Marcel Offermans <marcel.offermans@luminis.nl> wrote on 2007-05-22 
> On May 22, 2007, at 18:07 , Richard S. Hall wrote:
> > Since the overall response has been positive (even though I am 
> > mostly in the "excess cruft" camp with Eric), I have gone ahead and 
> > added it.
> I'm also in that camp, but I was at a conference (without internet) 
> today, so I missed out on the initial discussion.
> I'm wondering, if ServiceTracker was supposed to be part of the 
> framework, why didn't OSGi define it as such. 

Well, we weren't that bright in Release 1 :-) We learned shortly after 
Release 1 that the Service API is too hard to use correctly and thus added 
ServiceTracker in R2. Had we been smart enough up front, there may have 
only ever been ServiceTracker.

> Since it's not part of 
> the framework, I don't like including it in Felix by default. 

It is not part of the framework package, but it is a key class to use for 
services. Perhaps OSGi should consider moving it from Compendium to Core 

> It just 
> increases the size of the core.

14KB won't break the bank.

> So in my opinion we should not include it by default.
> > Of course, BND could solve this by having people just pull ST into 
> > their bundle. But if everyone were to do this, then the savings we 
> > see by not having ST in the framework JAR would be quickly 
> > outweighed by the multiple copies of ST embedded into all of the 
> > bundles that use it.
> If people don't need the whole compendium, they are free to create a 
> meaningful subset of it and use that. That's the other option they have.

Yes, but you raise the bar for people to use the framework correctly.

> If people are using another dependency manager (such as iPOJO) then 
> they don't need to use ST and you might actually want to discourage 
> people from using it at all by not providing it.

I don't think that is a good idea. iPOJO, DS, etc. cannot be used for all 
service needs. ST is a fundamental tool that should always be provided.



BJ Hargrave
Senior Technical Staff Member, IBM
OSGi Fellow and CTO of the OSGi Alliance

office: +1 386 848 1781
mobile: +1 386 848 3788

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