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

[Brian Stansberry]

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