[wildfly-dev] EE level java:comp/DefaultDataSource for WildFly 8...

[David M. Lloyd]

On 09/24/2013 01:03 PM, Eduardo Martins wrote:
> +1
>
> There are two other concerns I have with 3):
>
> 1) EE binds are done at java:comp or java:module, depending on module/component. Generic blind binding in every instance of a namespace may not be an option for the EE default bindings.

I believe this statement to be patently false.  The only case this might 
be true is WARs - but in a WAR, java:comp is just an alias for 
java:module so the same logic will always work in either case.  Now it 
may in fact be possible to create a conflicting binding, but that's a 
different problem.

> 2) Overridden of defaults through jboss app and jboss component xml descriptors, something I have planned for EE Concurrency default binds, may be much more complex to achieve.

Let's just take one step at a time OK? :-)

> I still like the feature, but think it will not help that much for handling EE default bindings.
>
> --E
>
> On Sep 24, 2013, at 4:00 PM, Brian Stansberry <brian.stansberry at redhat.com> wrote:
>
>> Ok, so that's a generic feature.  Seems like a scary generic capability
>> to me, but I'm not as familiar as you guys are with how these namespaces
>> work.
>>
>> On 9/24/13 9:54 AM, David M. Lloyd wrote:
>>> I think it means the config will continue to work just as it does,
>>> except Jeff's error message won't happen anymore.  Bindings in
>>> non-global namespaces would materialize in every instance of that namespace.
>>>
>>> On 09/24/2013 09:50 AM, Brian Stansberry wrote:
>>>> 3) is confusing. If it's naming binding stuff, putting it in naming or
>>>> in the relevant subsystem seems more intuitive.
>>>>
>>>> What does 1) really mean in terms of config? Something generic? Or
>>>> something quite specific that results in the appropriate bindings?
>>>> Generic makes me nervous as it opens up a whole new broad feature with
>>>> many possible ways it could be broken.
>>>>
>>>> I like 1) better than 2) if my concern above can be addressed.
>>>>
>>>> On 9/24/13 9:12 AM, David M. Lloyd wrote:
>>>>> On 09/24/2013 05:14 AM, Eduardo Martins wrote:
>>>>>> Maybe we should create a doc with a reference design, since there are several default EE resources among our subsystems...
>>>>>>
>>>>>> IMHO default EE resources should be defined in the related subsystem configuration, otherwise the EE subsystem config will always be changing. In this case there should a configuration in the Datasources subsystem such as:
>>>>>>
>>>>>> <subsystem xmlns="urn:jboss:domain:datasources:2.0">
>>>>>>            <datasources>
>>>>>>            		<default-datasource jndi-name="java:jboss/datasources/ExampleDS" />
>>>>>> 		<datasource jndi-name="java:jboss/datasources/ExampleDS" pool-name="ExampleDS" enabled="true" use-java-context="true">
>>>>>> 			...
>>>>>> 	        </datasource>
>>>>>>             	...
>>>>>>            </datasources>
>>>>>> </subsystem>
>>>>>>
>>>>>> For an easier/faster logic to find the default resource, and since we don't officially support linkref on jndi, the subsystem management op that adds the default resource (in this case default-datasource) should create a binder service pointing to a *fixed* jndi name (let's says java:jboss/ee/default/datasource) and inject it with the target resource (in this case the jndi name java:jboss/datasources/ExampleDS).
>>>>>>
>>>>>> Then the subsystem should provide a DUP that for EE modules do the required default bindings, in this case java:comp/DefaultDataSource and/or java:module/DefaultDataSource
>>>>>>
>>>>>> The subsystem then also needs to take care of the default mapping to the *fixed* jndi name from @Resource injection, this can be accomplished by adding a EEResourceReferenceProcessor to the EEResourceReferenceProcessorRegistry present in DU attachment with key org.jboss.as.ee.component.Attachments.RESOURCE_REFERENCE_PROCESSOR_REGISTRY
>>>>>
>>>>> I don't know, I guess I'm running out of opinion on this.
>>>>>
>>>>> Here's a list of options:
>>>>>
>>>>> 1) Enhance naming subsystem to be able to bind java:comp, java:module,
>>>>> java:app names, and put config in that subsystem (modify JMS and other
>>>>> subsystems with implicit bindings to do the same)
>>>>> 2) Enhance datasources subsystem to include a default datasource
>>>>> attribute (== XML element) which, when present, will set up implicit
>>>>> bindings for java:comp (and make sure that the config looks/acts
>>>>> similarly between JMS, DS, and any other subsystem with implicit bindings)
>>>>> 3) Decide it's all the EE subsystem and put implicit bindings in there
>>>>>
>>>>> Decision time: GO!
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>> --
>> Brian Stansberry
>> Principal Software Engineer
>> JBoss by Red Hat
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>
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