code: protected AnnotationAttributes getAttributes(AnnotationMetadata metadata) {
  		String name = getAnnotationClass().getName();
  		AnnotationAttributes attributes = AnnotationAttributes
  				.fromMap(metadata.getAnnotationAttributes(name, true));
  		Assert.notNull(attributes,
  				() -> "No auto-configuration attributes found. Is "
  						+ metadata.getClassName() + " annotated with "
  						+ ClassUtils.getShortName(name) + "?");
  		return attributes;
  	}
docs: Return the appropriate {@link AnnotationAttributes} from the
  {@link AnnotationMetadata}. By default this method will return attributes for
  {@link #getAnnotationClass()}.
  @param metadata the annotation metadata
  @return annotation attributes