Dates and Times - Beginning Java 8 Fundamentals - page 419

Human-Scale Time
In the previous section, I discussed the use of Instant and Duration classes whose instances are more suited to
dealing with machine-scale time. Humans deal with time in terms of fields such as year, month, day, hour, minute,
and second. Recall the following format for specifying date and time in ISO-8601 format:

[date]T[time][zone offset]

The Date-Time API provides several classes, listed in Table 12-2 , to represent all fields and their combinations of
human-scale time. A Yes or No in the component column for a class indicates whether an instance of the class stores
that component or not. I will discuss all of these classes in detail shortly.

Table 12-2. Human-Scale Date and Time Classes and their Components

Class Name Date Time Zone Offset Zone Rule

LocalDate

Yes No No No

LocalTime

No Yes No No

LocalDateTime

Yes Yes No No

OffsetTime

No Yes Yes No

OffsetDateTime

Yes Yes Yes No

ZonedDateTime Yes Yes Yes Yes

ZoneOffset No No Yes No

ZoneId No No Yes Yes

The ZoneOffset Class
An instance of the ZoneOffset class represents a fixed zone offset from UTC time zone, for example, +05:30, -06:00, etc.
It is a period of time that a time zone differs from the UTC.
A ZoneOffset is not aware of the changes in zone offset because of the observed Daylight Saving Time.
The ZoneOffset class declares three constants:

• UTC

MAX •

MIN
UTC is the time zone offset constant for UTC. MAX and MIN are the maximum and minimum supported zone offsets.

•

■ Tip Z, not +00:00 or -00:00, is used as the zone offset designator for UtC time zone.

The ZoneOffset class provides methods to create its instances using a combination of hour, minute, and second.
Listing 12-3 demonstrates how to create instances of the ZoneOffset class.