question: @ Override public Range findRangeBounds ( XYDataset dataset ) { if ( dataset == null ) { return null ; } double min = Double . POSITIVE_INFINITY ; double max = Double . NEGATIVE_INFINITY ; TableXYDataset d = ( TableXYDataset ) dataset ; int itemCount = d . getItemCount ( ) ; for ( int i = 0 ; i < itemCount ; i ++ ) { double [ ] stackValues = getStackValues ( ( TableXYDataset ) dataset , d . getSeriesCount ( ) , i ) ; min = Math . min ( min , stackValues [ 0 ] ) ; max = Math . max ( max , stackValues [ 1 ] ) ; } if ( min == Double . POSITIVE_INFINITY ) { return null ; } return new Range ( min , max ) ; }
target:  Returns the range of values the renderer requires to display all the items from the specified dataset.