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From Peter Donald <pe...@apache.org>
Subject RE: [Proposal] Avalon 5.0 directory
Date Mon, 10 Jun 2002 06:06:32 GMT
At 01:10 AM 6/10/2002 -0400, you wrote:
> > >That way we can have a look at and play with the interfaces until we
> > >like them.
> >
> >
> > Dont like the idea of hints and especially hate the idea that
> > hints be objects
>Pete, what's wrong with this?

Do I have to say it again? ;) Okay lets try it another way ...

Why is it needed?

Lets assume component A requires the GreasyBurger service. There is two 
types of GreasyBurder service "McChucks" and "GooberBurger".

When A looks up the service it does not care that there are two 
varitys/hints it just cares about the one that it has been assigned BY THE 
ASSEMBLER. So it does not need to worry about hints or anything like that.

So what type of component will use the hints? Any component that has to 
access multiple different types of same service. Component B is one such 
service - it uses one burger at breakfast and one at lunchtime. So it uses 
the hint "lunchtime" to access lunchtime GreasyBurger instance. Note it is 
UP TO THE ASSEMBLER to wire the correct components in. The ASSEMBLER could 
quite easily wire the McChucks in as breakfast or lunchtime with equal ease.

So why did the notion of hints ever infect the framework? It was introduced 
because people wanted a global namespace (erk) as they were treating the 
ComponentManager as a container (erk erk) and they wanted to have the 
component develoeprs mix concerns with assembler (erk erk erk).

>It is more clear to the user that what we are trying to get.  It
>follows a standard that is used to obtain i18n, JSSE, JCE, etc.
>objects.  You have the default no-arg lookup, and then one to
>fine tune it.

You cite that you want the ComponentManager to be a ServiceDirectory yet 
you site examples of ResourceManagers and Factorys as why you should have a 
feature. Can you site a ServiceDirectory that has similar features. As far 
as I am aware none of JNDI, LDAP, ActiveDirectory, NDIS, DNS or any other 
directory service that I know of has any such notion of hints.

>What do you see as being better?

Simple string lookup - no hints or any second parameter - like all the 
other directy apis except simpler.


Peter Donald
"Faced with the choice between changing one's mind,
and proving that there is no need to do so - almost
everyone gets busy on the proof."
              - John Kenneth Galbraith

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