[type-annos-observers] FYI, JSR 308 and the annotation processing discovery process

[Joe Darcy]

Hello,

FYI, as the JSR 269 maintenance lead, besides updating the 
javax.lang.model.* API to handle new-in-Java-SE-8 features, I'm not 
looking at updating the javax.annotation.processing API to deal with 
those new annotation-related features too.

To provide some context, here is an excerpt from the 
javax.annotation.processing.Processor interfaces which describes part of 
the tool <-> processor protocol:

"The tool uses a discovery process to find annotation processors and 
decide whether or not they should be run. [...] Which processors the 
tool asks to run is a function of what annotations are present on the 
root elements, what annotation types a processor processes, and whether 
or not a processor claims the annotations it processes. [...] For a 
given round, the tool computes the set of annotation types on the root 
elements. If there is at least one annotation type present, as 
processors claim annotation types, they are removed from the set of 
unmatched annotations."

To this, I plan to add a paragraph explaining how type annotations do 
not interact with the this discovery process; something like:

"<p>An annotation type is considered present if there is at least one
annotation of that type on a declaration enclosed within the root
elements of a round. For this purpose, a type parameter is considered
to be enclosed by its generic element. Annotations on type uses are
<em>not</em> considered as part of the computation.

An annotation is <em>present</em> on a declaration if it is present as
defined in {@link AnnotatedConstruct}. That is, the annotation may be
directly present or present via inheritance. An annotation indirectly
present by virtue of a repeatable annotation type is <em>not</em>
considered represent for the purposes of the discovery process.

[..]"

For the purposes of JSR 308:

* Declaration annotations on type parameters are included in discovery
* TYPE_USE annotations are *not* included as part of discovery

Comments?

Thanks,

-Joe