public GroupMerger(Sort groupSort) {groupComp = new GroupComparator<>(groupSort);queue = new TreeSet<>(groupComp);groupsSeen = new HashMap<>();}

public GroupMerger(Sort groupSort){groupComp = new GroupComparer<T>(groupSort);queue = new JCG.SortedSet<MergedGroup<T>>(groupComp);groupsSeen = new JCG.Dictionary<T, MergedGroup<T>>();}
