Assuming I have the simple POJO Meal:
public class Meal
{
LocalDate mealtime;
int calories;
}
which is then collected in a List:
List<Meals> meals;
How I can use streams to get a list that totals the calories consumed on a monthly basis over several years. It's very easy to tabulate based on the month alone but I want to create a bar chart spread over several years to compare the consumption of calories over time and NOT just by month.
How can this be done? Do I have to create some complex structure of Instant objects with months and Years using HashMaps of years and months or is there a better way?