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From Jeff Genender <jgenen...@apache.org>
Subject Re: Spring integration...
Date Tue, 08 Feb 2005 23:50:37 GMT
I think Jules has a point on this.  What about the use of other open 
source projects that manage thier own private mbean lifecycles, such as 
Tomcat?

A significant portion of the Tomcat underbelly infrastructure is managed 
this way.

In the debugconsole, I can see the Tomcat created mbean objects.  But 
when I try to manage them (view, etc), the debugconsole throws an 
Exception that the object is not a gbean.  I don't know of this is 
directly related, but it would be nice for gernimo to allow the plugged 
in components to manage thier own mbean lifecycles, and to be exposed.

Jeff


Dain Sundstrom wrote:
> I am definitely against this change.  A fundamental assumption of the 
> current GBean code is it controls life-cycle, and I believe changing 
> this would have a massive impact on the entire GBean architecture.  I do 
> believe that you could get it to work for your small use case, but I 
> believe that the impact will be much larger then a small use case.  
> Further, I believe that you can use a delegation model to achieve this 
> today without a kernel patch.
> 
> I'm not saying that this should never change, but that this is not the 
> time.  After certification, I would like to spend time rethinking the 
> GBean architecture.  Specifically, I'd like to make it trivial to 
> integrate Spring, Avalon, Pico, etc. components, and I'd like to make it 
> easier to program with GBeans.  This means, taking a second look at the 
> info object, data object, xml configuration, persistence, dispatching 
> and life-cycle.  Anyway, this is something I believe can wait.
> 
> -dain
> 
> 
> On Feb 8, 2005, at 1:55 AM, Jules Gosnell wrote:
> 
>> So, Guys,
>>
>> I've given you a few days to look over the minimal kernel patch.
>>
>> As I understood it we left the thread with two real options :
>>
>> 1) extend the kernel to allow acceptance of an existing object for 
>> proxying via GBeanInstance, rather than always constructing such 
>> objects itself.
>>
>> 2) submit a dynamically crafted class and required instance (as 
>> constructor arg for said class). when class is instantiated and 
>> injected result will be a proxy that is [largely] semantically 
>> identical to (1). We must be able to proxy non-interfaces and final 
>> methods.
>>
>> To summarise the debate over the two options :
>>
>> against (1), for (2)
>> understandable reticence to change the kernel
>> concern over the kernel losing explicit ownership of the life-cycle of 
>> the object that it is managing
>>
>> for (1), against (2)
>> we are talking about an extension, not a backwardly incompatible 
>> change to the kernel
>> I have demonstrated that such an extension would have minimal 
>> footprint and implication
>> (2) does not restore lifecycle ownership to the kernel
>> (2) is complex, less efficient and will need to be repeated anywhere 
>> someone needs this fn-ality
>> (1) is simpler, more efficient and will only need to be done once
>>
>> Finding a resolution to this is, IMHO, critical to the Spring 
>> integration. Otherwise I would let it go.
>>
>> I had a very similar problem integrating two other well known pieces 
>> of open source some time ago. The host had a JMX kernel and the thing 
>> that I was embedding had internal MBeans with their own private 
>> lifecycles. I persuaded the powers-that-were to allow MBeans that were 
>> not managed by the kernel to be exposed via it. A change was made. The 
>> extension to the kernel was never rescinded. In fact, at least one 
>> other integration now makes use of it. It enabled embedded components 
>> to open themselves up to the services supplied by the kernel in a way 
>> that could not be done before...
>>
>> I humbly await your judgement :-)
>>
>>
>> Jules
>>
>>
>>
>> -- 
>> "Open Source is a self-assembling organism. You dangle a piece of
>> string into a super-saturated solution and a whole operating-system
>> crystallises out around it."
>>
>> /**********************************
>> * Jules Gosnell
>> * Partner
>> * Core Developers Network (Europe)
>> *
>> *    www.coredevelopers.net
>> *
>> * Open Source Training & Support.
>> **********************************/

-- 
Jeff Genender
http://geronimo.apache.org


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