Retrieving values from JFreeChart pie dataset

Question

I am reading from a csv file formatted with a student name, date they are absent, and an integer value of 1. The file looks like this:

Jim,8/19/2016,1
Jim,8/20/2016,1

I am plotting this data on a piechart using JFreeChart, and I can set labels to show the sum of absences for each student or the percentage, but I want to store the sum and percentage as variables and use them later in my code. How do I do this? My next step would be seeing if Jim missed more than 25% of the days in the school year.

Answer 1

DatasetUtilities.calculatePieDatasetTotal "Calculates the total of all the values in a PieDataset." The corresponding source shows a typical iteration scheme.

List keys = dataset.getKeys();
while (iterator.hasNext()) {
    Comparable current = (Comparable) iterator.next();
    Number value = dataset.getValue(current);
    …
}

You can change the displayed percentage labels as shown here.

In your next step, the number of days in the school year is particular to a given school system. the number of days should be supplied as a parameter to the method that iterates through the PieDataset.