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JSR 310 Date and Time - Choices - Calendar internal storage
This choice is about how to store data inside calendars.
Option 1 - year / month / day / hour / min / sec
This option would store data using the basic 6 fields.
Unusual calendar systems would choose their own most important fields.
Advantages:
- get/set to any of these specific fields is very quick
- resolving invalid dates is obvious, as the leapyear/month/day combination is easy to check
- add of small amounts within stored fields is easy
Disadvantages:
- get/set to any other field is slow
- difficult to represent an object like YearWeek (weekyear + week of year) as it doesn't fit
- add requires complex calculation
Option 2 - duration from epoch in seconds
This option would store data using seconds.
Advantages:
- get/set to all fields is calculated, those below day are quick
- add is quick for all fields except month/year
- able to represent any calendar, including ones like YearWeek (weekyear + week of year)
- compareTo/equals/hashcode are quick
- conversion to an instant is quick
Disadvantages:
- get/set to all fields requires calculation
- resolving invalid dates requires calculation of each of year/month/day
- get/set day/month/year requires complex calculation
- add month/year requires complex calculation
Option 3 - duration from epoch in seconds and months
This option would store data using the 2 durations - seconds and months.
Unusual calendar systems would choose their own fields (the ones with discontinuities).
Advantages:
- get/set to all fields is calculated, most calculations (esp. day/month/year) are quick
- add is quick for all fields (unless an unusual field is not based on a standard field)
- able to represent any calendar, including ones like YearWeek (weekyear + week of year), eg. by storing 1 duration in weeks
- add month/year is quick
Disadvantages:
- get/set to all fields requires calculation, but this is quick
- resolving invalid dates requires calculation of each of year/month/day, but this is quick
- add fields below month requires potentially complex calculation if they go over 28 days
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