@Override
    public int compare(Hit h1,Hit h2) {
        int primaryOrder=sourceOrderCompare(h1,h2);
        if (primaryOrder!=0) return primaryOrder;

        return super.compare(h1,h2);
    }
Creates a source order comparator, with an optional secondary comparator.

@param sourceOrder the sort order of list names. This list gets owned by this and must not be modified
@param secondaryComparator the comparator to use as secondary, or null to use the intrinsic hit order
container-search/src/main/java/com/yahoo/search/pagetemplates/engine/SourceOrderComparator.java