JDK 9 request for specification changes of JDK-8032230: Enhance javax.a.p.RoundEnvironment after repeating annotations

[joe darcy]

Hello,

Please review the patch below which proposes a new method to address

     JDK-8032230: Enhance javax.a.p.RoundEnvironment after repeating 
annotations

At present, this is just a review of the specification of the default 
method in the interface and *not* a more optimized implementation in the 
javac RoundEnvironemnt implementation (and not any tests that would be 
needed for the new functionality).

Note that the bug proposes adding two methods

     RoundEnvironment.getElementsAnnotatedWith(Set<Class<? extends 
Annotation>> s)
RoundEnvironment.getElementsAnnotatedWith(Set<AnnotationMirror> s)

but these methods would clash since their erasure is the same. *sad 
tromphone*

Therefore, I'm only proposing to add the Class-based variant since that 
one is the more commonly used of the two.

Thanks,

-Joe


+    /**
+     * Returns the elements annotated with any of the given annotation
+     * types.
+     *
+     * @apiNote This method may be useful when processing repeating
+     * annotations by looking for an annotation type and its
+     * containing annotation type at the same time.
+     *
+     * @implSpec The default implementation of this method creates an
+     * empty result set, iterates over the annotations in the argument
+     * set calling {@link #getElementsAnnotatedWith(TypeElement)} on
+     * each annotation and adding those results to the result
+     * set. Finally, the contents of the result set are returned as an
+     * unmodifiable set.
+     *
+     * @param annotations  annotation type being requested
+     * @return the elements annotated with the given annotation types,
+     * or an empty set if there are none
+     * @throws IllegalArgumentException if the any elements of the
+     * argument set do not represent an annotation type
+     * @since 9
+     */
+    default Set<? extends Element> getElementsAnnotatedWith(Set<Class<? 
extends Annotation>> annotations){
+        HashSet<Element> result = new HashSet<>();
+        for (Class<? extends Annotation> annotation : annotations) {
+            result.addAll(getElementsAnnotatedWith(annotation));
+        }
+        return Collections.unmodifiableSet(result);
+    }