In java, How to fill the missing date range with data ?

Question

Im having two files one with date range and another file with (date range , values)
We need to write an output with matching date range and values, default value is given for missing date ranges

1/1/2022 to 4/30/2022 - red
6/30/2022 to 10/31/2022 - blue
For the missing date range i need to fill with value green
Expected OUTPUT:
1/1/2022 -4/30/2022 = red
5/1/2022 -5/31/2022 = green
6/30/2022 -10/31/2022= blue
11/1/2022 -12/31/2022 = green

Answer 1

Use java.time.LocalDate.datesUntil() method to define a range of consecutive days, which are represented as Stream<LocalDate>

You can compare dates with LocalDate.isBefore, isEqual, isAfter methods.

https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/time/LocalDate.html#datesUntil(java.time.LocalDate)