code: public static <ITEM extends Item> Predicate<ITEM> isBuildable() {
          return new Predicate<ITEM>() {
              public boolean apply(ITEM item) {
                  return item instanceof Job ? ((Job<?, ?>) item).isBuildable() : item instanceof BuildableItem;
              }
          };
      }
docs: Can be useful to ignore disabled jobs on reregistering hooks
  
  @return predicate with true on apply if item is buildable