if ( left == null || right == null ) { throw new DataException( ResourceConstants.UNEXPECTED_ERROR ); }
	private JointResultMetadata getJointResultMetadata( IResultMetaData left,			IResultMetaData right ) throws DataException	{		try		{			String leftPrefix = dataSet.getLeftDataSetDesignName( );			String rightPrefix = dataSet.getRightDataSetDesignName( );			if ( leftPrefix.equals( rightPrefix ) )			{				leftPrefix = leftPrefix + "1";				rightPrefix = rightPrefix + "2";			}			leftPrefix = leftPrefix + COLUMN_NAME_SPLITTER;			rightPrefix = rightPrefix + COLUMN_NAME_SPLITTER;			JointResultMetadata meta = populatorJointResultMetadata( left,					leftPrefix,					right,					rightPrefix );			return meta;		}		catch ( BirtException be )		{			throw DataException.wrap( be );		}	}