public Comparator<? super K> comparator() { return getDelegate().comparator(); }
public K firstKey() { return getDelegate().firstKey(); }
public K lastKey() { return getDelegate().lastKey(); }
public SortedMap<K, V> subMap(final K fromKey, final K toKey) { return Collections.unmodifiableSortedMap(getDelegate().subMap(fromKey, toKey)); };
public SortedMap<K, V> headMap(final K toKey) { return Collections.unmodifiableSortedMap(getDelegate().headMap(toKey)); };
public SortedMap<K, V> tailMap(final K fromKey) { return Collections.unmodifiableSortedMap(getDelegate().tailMap(fromKey)); };