code: static Optional<AnnotationMirror> getAnnotationMirror(Element element,
        Class<? extends Annotation> annotationType) {
      String annotationName = annotationType.getName();
      for (AnnotationMirror annotationMirror : element.getAnnotationMirrors()) {
        if (getQualifiedName(annotationMirror.getAnnotationType()).contentEquals(annotationName)) {
          return Optional.of(annotationMirror);
        }
      }
      return Optional.absent();
    }
docs: Get the {@link AnnotationMirror} for the type {@code annotationType} present on the given
  {@link Element} if it exists.