saveNullRowsBetween( lastRowIndex, currIndex );
	private void saveExprOfCurrRow( int lastRowIndex, int currIndex )			throws IOException	{		saveNullRowsBetween( lastRowIndex, currIndex );				Set keySet = exprValueMap.keySet( );		String[] exprIDs = (String[]) keySet.toArray( new String[0] );				int size = exprIDs.length;		IOUtil.writeInt( dos, size );		for ( int i = 0; i < size; i++ )		{			String exprID = exprIDs[i];			Object exprValue = exprValueMap.get( exprID );			IOUtil.writeString( dos, exprID );			IOUtil.writeObject( dos, exprValue );		}	}