public final void refresh() {
final Map<K, V> mTemp = new TreeMap<K, V>();
final Map<V, List<K>> mRevTemp = new TreeMap<V, List<K>>();
final DBFunctions db = getDB();
while (db.moveNext()){
final K key = readKey(db);
final V val = readValue(db);
mTemp.put(key, val);