[seam-dev] Extending weld-extensions generic beans
After talking with Tihomir over the last few days about the seam-drools module I think
that there is base functionality that is missing that belongs in weld-extensions as it is
similar to the existing generic bean code.
I will use an example from the drools module to outline the problem:
The drools module has a DroolsConfiguration object that contains configuration, this can
be installed via XML and there can be multiple DroolsConfigrations per app. for every
DroolsConfiguration several object need to be produced e.g. KnowledgeBase,
StatefullKnowledgeSession and a KnowledgeRuntimeLogger.
currently we would need to do something like this:
< d:DroolsConfiguration>
<app:SomeQualifier>
...configuration
</d:DroolsConfiguration>
<d:KnowlegdeBaseProducer>
<d:producerMethod>
<app:SomeQualifier>
<s:parameters>
<d:DroolsConfiguration>
<s:Inject/>
<app:SomeQualifier/>
</d:DroolsConfiguration>
</s:parameters>
</d:producerMethod>
</d:KnowlegdeBaseProducer >
...same for StatefullKnowledgeSession, StatelessKnowledgeSession, KnowledgeRuntimeLogger
etc.
and wire up a producer like that for every object being created from the
DroolsConfiguration. This is not good. The user should be able to just wire up the
configuration and the rest of the beans should be created automatically. I think we should
be able to do something like this:
@Generic(DroolsConfiguration.class)
class KnowledgeBaseProducer
{
@Produces
@GenericQualifiers
public KnowledgeBase producerMethod(@Inject @GenericQualifiers DroolsConfiguration
config )
{
//do stuff
}
}
@Generic tell the extensions to register a new KnowledgeBaseProducer bean for every
DroolsConfiguration found.
@GenericQualifiers is replaced with the qualifiers on the DroolsConfiguration object when
the bean is added.
This means that all an end user has to do is wire up a single DroolsConfiguration object
and everything just works.
Does this sound like a good idea? Is there anything I have overlooked?
Stuart