I have two ZonedDateTime instances:
final ZonedDateTime a = ...;
final ZonedDateTime b = ...;
I want to get the maximum of those two values. I want to avoid having to write custom ad-hoc code.
What is the best way to do this in Java 8? I am currently doing it as following:
final ZonedDateTime c = Stream.of(a, b).max(ChronoZonedDateTime::compareTo).get();
Are there better approaches?
You can simply call isAfter:
ZonedDateTime max = a.isAfter(b) ? a : b;
or since the class implements Comparable:
a.compareTo(b);
As pointed out by OleV.V. in the comments it's a difference between the two methods for comparing times. So they might produce different results for the same values
DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE_TIME;
ZonedDateTime time1 = ZonedDateTime.from(formatter.parse("2019-10-31T02:00+01:00"));
ZonedDateTime time2 = ZonedDateTime.from(formatter.parse("2019-10-31T01:00Z"));
System.out.println(time1.isAfter(time2) + " - " + time1.isBefore(time1) + " - " + time1.isEqual(time2));
System.out.println(time1.compareTo(time2));
Generates
false - false - true
1
ZonedDateTime implements Comparable interface so you can simple use Collections.max
Collections.max(Arrays.asList(a,b));