code: public static <FACETTYPE extends Facet<?>> Set<Class<FACETTYPE>> getAllRequiredFacets(final Class<?> inspectedType)
     {
        Set<Class<FACETTYPE>> seen = new LinkedHashSet<Class<FACETTYPE>>();
        return getAllRelatedFacets(seen, inspectedType, FacetConstraintType.REQUIRED);
     }
docs: Inspect the given {@link Class} for all {@link FacetConstraintType#REQUIRED} dependency {@link Facet} types. This
  method inspects the entire constraint tree.