@Override
  public boolean reseek(ExtendedCell seekCell) {
    while (iter.hasNext()) {
      ExtendedCell next = iter.next();
      int ret = comparator.compare(next, seekCell);
      if (ret >= 0) {
        current = next;
        return true;
      }
    }
    return false;
  }
Utility scanner that wraps a sortable collection and serves as a KeyValueScanner.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java