[jboss-as7-dev] Web UI: Profile & host sections mutable?

[David M. Lloyd]

On 02/14/2011 11:27 AM, Brian Stansberry wrote:
> On 2/14/11 11:14 AM, David M. Lloyd wrote:
>> The way we've solved this in other subsystems is by introducing optional
>> dependencies at the service level.  For example if the transaction
>> subsystem is configured with an ORB present, we configure JTS, otherwise
>> we do not; if OSGi and Txn are both present, then OSGi exposes the Txn
>> service.
>>
>> I'm not 100% certain we can extend this technique to all cases, but I
>> think we should at least try to.  JCA for example would obviously be
>> quite crippled without JTA.  So I do not have an answer to that case;
>> maybe it suffices to print a warning message in this case.  We should at
>> least explore it before we throw out the idea though.
>
> Let's assume for the sake of argument that we want to expose dependency
> info via the management interface. I see here hard dependencies (e.g.
> presumably JCA and JTA) and optional. Extensions could register these
> dependencies when they initialize. It opens up a can of worms though, as
> we'd need a proper language to describe the dependencies.

Yeah the can of worms is what I seek to avoid, though it might be 
inevitable eventually.

> Thinking out loud here, could we use the module dependency information
> for this?  Nah, that would just say, e.g. that JCA needs the JTA APIs,
> but says nothing about the impl.

I don't think module deps would cut it for this use case.  The 
dependency exists at purely a subsystem level, not at a module level, 
and imposing a constraint between the two just for this reason really 
rubs me the wrong way; anyway module dependencies are not by any means 
static (we just use them that way, most of the time) and are definitely 
not suitable as management layer metainformation.

-- 
- DML