Recently started using the lambda in Java.
Map<Category, Double> lMap = rptData.stream().collect(Collectors.groupingBy(Expense::getCategory,
Collectors.summingDouble(j -> j.getFltAmt().doubleValue())));
The above code returns map, which returns out put of rest service as JSON.
{"Category(intCatId=10013, strCatName=Home Maint)":4134.99,"Category(intCatId=10019, strCatName=Lease Breakage)":2600.0,"Category(intCatId=10011, strCatName=Utility Bill)":2067.76,"Category(intCatId=10010, strCatName=Fuel)":1018.77,"Category(intCatId=10012, strCatName=Entertainment)":192.4,"Category(intCatId=6, strCatName=Shopping)":1528.25,"Category(intCatId=4, strCatName=Medicine)":128.55,"Category(intCatId=10021, strCatName=Interest)":24.61,"Category(intCatId=3, strCatName=Phone)":539.09,"Category(intCatId=10020, strCatName=Movers)":1350.0,"Category(intCatId=5, strCatName=Grocery)":3519.83,"Category(intCatId=8, strCatName=School)":311.0,"Category(intCatId=10009, strCatName=Insurance)":1117.75,"Category(intCatId=7, strCatName=Eating Out)":614.22,"Category(intCatId=1, strCatName=Vehicle)":2843.58,"Category(intCatId=10018, strCatName=Courier)":22.65,"Category(intCatId=2, strCatName=Rent)":16506.95,"TotCount":13.0,"Category(intCatId=10017, strCatName=Travel)":800.42,"Category(intCatId=10015, strCatName=Donation)":326.0}
In the above JSON I have whole Category as key in map, instead I am looking for just the intCatId. So the output will be like
{"10013":4134.99,"10019":...}
Is there any way?
Example:
Domain
Expense{ Double fltAmt Date dtDate (formula "month(dtDate) - year(dtDate)") String monthYear (joinedby intCatId) Category category ... }
Category{ int intCatId String CatName ... }
I want to get average of (sum of all expense amounts by category and monthYear) by monthYear.
In above example, rptData is List with sum(fltAmt), monthYear and Category.
Edited as per Shamseer comments
You almost did it.
All you need is change the Map<Category, Double> to Map<Integer, Double> and then, in the grouping function, substitute Expense::getCategory for another lambda e -> e.getCategory().getIntCatId() (there is a getter for intCatId, right?)
This will produce the following output:
{10013:4134.99,10019:...}