code: public QuadTreeIterator getIterator(boolean bSorted) {
  		if (!bSorted) {
  			QuadTreeImpl.QuadTreeIteratorImpl iterator = m_impl.getIterator();
  			return new QuadTreeIterator(iterator, false);
  		} else {
  			QuadTreeImpl.QuadTreeSortedIteratorImpl iterator = m_impl.getSortedIterator();
  			return new QuadTreeIterator(iterator, true);
  		}
  	}
docs: Gets an iterator on the QuadTree.
  \param bSorted Put true to iterate the quad tree in the order of the Element_types.