public int hashCode() {
        return locale.hashCode() +
               strength.hashCode() +
               function.hashCode() +
               (isDescending() ? 13 : 0);
    }
A search-time document attribute sort specification(per-document in-memory value).
This belongs to the attribute or field(implicitt attribute).

@author baldersheim
config-model/src/main/java/com/yahoo/schema/document/Sorting.java