question: public static Range findCumulativeRangeBounds ( CategoryDataset dataset ) { ParamChecks . nullNotPermitted ( dataset , "dataset" ) ; boolean allItemsNull = true ; double minimum = 0.0 ; double maximum = 0.0 ; for ( int row = 0 ; row < dataset . getRowCount ( ) ; row ++ ) { double runningTotal = 0.0 ; for ( int column = 0 ; column <= dataset . getColumnCount ( ) - 1 ; column ++ ) { Number n = dataset . getValue ( row , column ) ; if ( n != null ) { allItemsNull = false ; double value = n . doubleValue ( ) ; if ( ! Double . isNaN ( value ) ) { runningTotal = runningTotal + value ; minimum = Math . min ( minimum , runningTotal ) ; maximum = Math . max ( maximum , runningTotal ) ; } } } } if ( ! allItemsNull ) { return new Range ( minimum , maximum ) ; } else { return null ; } }
target:  Calculates the range of values for a dataset where each item is the running total of the items for the current series.