[jboss-as7-dev] [jboss-as] Fix the default-stateful-access-timeout and default-singleton-access-timeout to be more consistent with the management model, by making them attributes (0b149ef)

[Heiko Braun]

Maybe this has been discussed elsewhere, but looking at the EJB description I can see that expressions are allowed basically anywhere.
This is an example how is should _not_ be done. I.e. the "default-mdb-instance-pool" is certainly not something you would like to configure by external means, do you?

Ike

On Oct 12, 2011, at 8:39 AM, Heiko Braun wrote:

> 
> 
> The question you should ask yourself is which parts should be configured externally?
> I.e. a typical scenario for expressions are configuration values that change depending on the environment (staging/production).
> 
> I would suggest to be _very_ conservative about allowing expressions in your model.
> It's definitely wrong to allow them anywhere, just because you are not sure if they make sense.
> As Brian said: We can add them anytime, but removing them is not an option.
> 
> Some further clarification what "adding expressions" actually means:
> 
> a) attribute meta data "expressions-allowed"
> b) expressions values that we provide out of the box
> 
> a) is a requirement for b). But you are not forced to provide b).
> 
> My advice: Support expressions when it makes real sense. But back your decision with some a use case.
> 
> Expressions are a powerful way to extend our default configuration means. 
> At the same time they lead to ambiguity and all kinds of error scenarios. So use them sparely.
> 
> 
> My 2 cents.
> 
> 
> Ike
> 
> On Oct 11, 2011, at 6:26 PM, Brian Stansberry wrote:
> 
>> But otherwise, go ahead and support 
>> it. Expressions will be very important in cloud use cases where 
>> customizing the config file on a per-server basis is a poor option.
> 
> 
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