Multiple aggregate functions in Java 8 Stream API

Question

I have a class defined like

public class TimePeriodCalc {
    private double occupancy;
    private double efficiency;
    private String atDate;
}

Answer 1

You can chain multiple attributes like this:

Collection collector = result.stream().collect(Collectors.groupingBy(p -> p.getAtDate(), Collectors.averagingInt(p -> p.getOccupancy())));

If you want more, you get the idea.