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From Dain Sundstrom <d...@iq80.com>
Subject Re: Global JNDI effectively required for Jee5
Date Wed, 07 Feb 2007 17:54:51 GMT
On Feb 7, 2007, at 8:01 AM, David Jencks wrote:

>> The problem is our users' applications will make use of mapped  
>> name in other application servers, and since every application  
>> server that I know if is implementing these with Global JNDI, it  
>> becomes a defacto standard and requirement for Jee5.  Moreover, I  
>> believe that our GlobalJNDI names must be simple normal names  
>> (i.e, not encoded abstract names) you would see in other  
>> application servers, because users will annotate their code with  
>> the mapped names, effectively locking in the Global JNDI names  
>> that they expect to work in our application server.
>
> umm, that assumes that either every other app server has come up  
> with exactly the same scheme for global jndi names so they are in  
> fact interoperable or that we can imitate everyone elses naming  
> scheme at once.

um, I'm not making that assumption.  I'm assuming that other systems  
are using Global JNDI for resolving refs and that users will have  
"normal" JNDI names hardcoded into their apps.  By normal names I  
would say that they are simple words separated by a '/' character.


>> So do you agree that Global JNDI is the defacto required  
>> implementation for these and other similar entries?
>
> no.
>
> Since the beginning of geronimo we've carefully stayed away from  
> relying on global jndi for  resolving references since it imposes  
> global constraints on what you can deploy at once in the app  
> server, despite every other app server I know of relying on global  
> jndi for resolving references.  I'm extremely reluctant to abandon  
> the lack of conflicts between apps that we have now to run after an  
> alleged similarity with other app servers without thorough  
> investigation of compatibility between other app servers and  
> thinking about other choices that would preserve the lack of  
> conflicts.

I understand your reluctance and know the history, but reality is  
*everyone* uses Global JNDI.  I challenge you to find a single JEE  
server that doesn't.  Since everyone does, it is the defacto  
standard, and it is becoming more ingrained into the specs.  I think  
we need give up on our custom system, and simply implement it the way  
everyone else dose.

> Note that the use of any particular style of name in such  
> annotations does not imply that the target is actually bound in  
> jndi: all it requires is that we can find the resource somehow.
>
> Two alternatives that I would prefer to global jndi are:
>
> 1. We know the type of the thing we're looking for, so we can  
> simply treat the provided string as an (extended) ejb-link,  
> resource-link, etc and search the ancestor tree of the current app  
> for a unique match.  IMO this would be a lot simpler to implement  
> that relying on global jndi, because we already have the code  
> implemented and don't have to bind anything anywhere.
>
> 2. "scoped" global jndi.  Each application gets a "global" jndi  
> tree that only includes stuff from itself and its ancestor graph.   
> This avoids conflicts and should satisfy those with a jndi fetish.

There is nothing wrong with either proposal, and either would be a  
step forward.  I just think we shouldn't invent something new and  
just give users what they expect.

-dain

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