// create data
Date d = dtf.parse("2010-08-23");
int n = 1000; // number of datapoints
for (int i = 0; i < n; i++) {
data.addRow();
data.setValue(i, 0, new Date(d.getTime()));
data.setValue(i, 1, customFunction(i) / 100);
data.setValue(i, 2, customFunction2(i) / 100);
d.setTime(d.getTime() + 1000 * 60); // steps of one minute
}