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From Jean-Baptiste Onofré ...@nanthrax.net>
Subject Re: Minimal karaf distro
Date Mon, 20 Jan 2014 11:52:16 GMT
I had the impression to read an e-mail from Peter Kriens ;)

I know DS interests. My point was more DS or Blueprint vs OSGi "native". 
It was not between DS and Blueprint.

I agree with your points, and they make sense. I have no problem to 
think about this for Karaf 4.0.0, but I would plan tests 
(usage/benchmark), etc as it may have an impact for users.

Regards
JB

On 01/20/2014 12:06 PM, Ioannis Canellos wrote:
>> @Ioannis: agree, but I wonder the value of using DS instead of Blueprint, or
>> the "overwork plumbing" to use pure OSGi insteand of DS or Blueprint ;)
>
> The value of using DS instead of Blueprint focuses around those areas:
> i) smaller footprint
> ii) proxy free
> iii) improved lifecycle management of components.
> iv) you get metatype metadata for free (less maintenance).
> v) increased control /  transparency -> way easier to diagnose issues
> (see scr commands and scr mbeans).
>
>  From my point of view the biggest problem with blueprint is that is
> the lacking lifecycle management features of DS.
> So in many cases, we currently register services, commands & mbeans,
> even if the core service required for all those is missing. Then we
> are using proxies or service trackers to wait or check if the service
> is actually there.
> Of course, this is no biggie (other than initializing and registering
> unusable objects) when we know that eventually everything is going to
> be there, but when you want to try to make things as decoupled as
> possible and go for the minimum this can be a problem. Why? because
> you can end up waiting forever on services that wait for a proxy and
> so on.
>
> An other really important point, is that when you are using DS, you
> are able to see and interact with the state of your components, see
> which components have unsatisfied dependencies and how your components
> are wired together. With blueprint everything is a black box.
>
> For these reasons I also feel that it doesn't worth going for a pure
> OSGi api solution, since you gain (i) & (ii) but still loose all the
> others and also have the burden of maintenance.
>

-- 
Jean-Baptiste Onofré
jbonofre@apache.org
http://blog.nanthrax.net
Talend - http://www.talend.com

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