public IStoredListIterator<T> establishListScan(boolean randomScan){
  if (!randomScan && !_supportFifoPerSegment && getNumSegments() > 1)   throw new RuntimeException("establishListScan non-random scans not supported");
  SegmentedListIterator<T> slh=_SLHolderPool.get();
  SegmentedListIterator<T> res=establishPos(slh,randomScan);
  if (res == null)   slh.release();
  return res;
}

public IStoredListIterator < T > establishListScan ( boolean randomScan ) { if ( ! randomScan && ! _supportFifoPerSegment && getNumSegments ( ) > 1 ) throw new RuntimeException ( "establishListScan non-random scans not supported" ) ; SegmentedListIterator < T > slh = _SLHolderPool . get ( ) ; SegmentedListIterator < T > res = establishPos ( slh , randomScan ) ; if ( res == null ) slh . release ( ) ; return res ; }
establish a scan position . we select a random segment to start from
