public boolean errorRaised()
Returns {@code true} if an error was raised in the prior round
of processing; returns {@code false} otherwise.

 public Set<Element> getElementsAnnotatedWith(TypeElement a)
Returns the elements annotated with the given annotation type.
The annotation may appear directly or be inherited.  Only
package elements and type elements included in this
round of annotation processing, or declarations of members,
constructors, parameters, or type parameters declared within
those, are returned.  Included type elements are {@linkplain
#getRootElements root types} and any member types nested within
them.  Elements in a package are not considered included simply
because a {@code package-info} file for that package was
created.

 public Set<Element> getElementsAnnotatedWith(Class<Annotation> a)
Returns the elements annotated with the given annotation type.
The annotation may appear directly or be inherited.  Only
package elements and type elements included in this
round of annotation processing, or declarations of members,
constructors, parameters, or type parameters declared within
those, are returned.  Included type elements are {@linkplain
#getRootElements root types} and any member types nested within
them.  Elements in a package are not considered included simply
because a {@code package-info} file for that package was
created.

 public Set<Element> getRootElements()
Returns the root elements for annotation processing generated
by the prior round.

 public boolean processingOver()
Returns {@code true} if types generated by this round will not
be subject to a subsequent round of annotation processing;
returns {@code false} otherwise.