return null;
return this.currentDataIterator;
	public IDataIterator nextResultIterator( ) throws BirtException	{		if( resultIter == null )			return null;		if (currentDataIterator == null || currentDataIterator.isAdvanced() == false)		{			currentDataIterator = new DataIterator( this, resultIter, selectedColumns, expressions );			return currentDataIterator;		}				return null;	}