The java.time.Clock.withZone(ZoneId zone) method is a method of Clock class which returns a clock copy of clock object on which this method is applied, with a different time-zone. If there is a clock and it is required to change the zone of clock but not other properties, then withZone() method is used. This method takes zone as parameter which is the time-zone in which it is required to change. It returns the clock with zone, same as passed zone in parameter.
Syntax:
public abstract Clock withZone(ZoneId zone)
Parameter: This method takes a mandatory parameter zone of type ZoneId, in which it is required to change the time-zone.
Returns: This method returns a clock copy of clock object on which this method is applied, with a different time-zone passed as parameter.
Example:
Code:
//Clock with default zone
Clock clock1=Clock.systemUTC();
ZoneId zone = ZoneId.of("Asia/Calcutta");
Clock clock2 = clock1.withZone(zone);
System.out.println(clock2.toString());
Output::
SystemClock[Asia/Calcutta]
Explanation::
when withZone() is called for Clock object clock1 with zoneId "Asia/Calcutta",
then the withZone() method will return a Clock whose Zone is "Asia/Calcutta".
Below programs illustrates withZone() method of java.time.Clock class:
Program 1: To create a clock with similar properties as First Clock but zoneId equal to “Asia/Calcutta” with the help of withZone().
// Java program to demonstrate// withZone() method of Clock class import java.time.*; // create classpublic class withZoneMethodDemo { // Main method public static void main(String[] args) { // create a base Clock with systemUTC() method Clock baseclock = Clock.systemUTC(); // get ZonedDateTime object from baseclock // clock instant to get date time ZonedDateTime baseTime = baseclock .instant() .atZone(baseclock.getZone()); // print details of ZonedDateTime System.out.println("ZonedDateTime of baseclock " + baseTime.toString()); // create ZoneId object with Zone Asia/Calcutta ZoneId zone = ZoneId.of("Asia/Calcutta"); // apply withZone() to change zone from utc to Asia/Calcutta Clock clockWithOtherZone = baseclock.withZone(zone); // get ZonedDateTime object from clockWithOtherZone // clock instant to get date time ZonedDateTime calcuttaTime = clockWithOtherZone .instant() .atZone(clockWithOtherZone.getZone()); // print details of ZonedDateTime System.out.println("ZonedDateTime of clockWithOtherZone " + calcuttaTime.toString()); }} |
ZonedDateTime of baseclock 2018-08-24T08:09:17.354Z ZonedDateTime of clockWithOtherZone 2018-08-24T13:39:17.539+05:30[Asia/Calcutta]
Program 2: Print the zoneId using getZone() for clock created by withZone().
// Java program to demonstrate// withZone() method of Clock class import java.time.*; // create classpublic class withZoneMethodDemo { // Main method public static void main(String[] args) { // create a base Clock with systemDefaultZone() method Clock baseclock = Clock.systemDefaultZone(); // print details of ZonedDateTime System.out.println("baseclock Zone:" + baseclock.getZone()); // create ZoneId object with Zone Asia/Calcutta ZoneId zone = ZoneId.of("Asia/Calcutta"); // apply withZone() to change zone // of baseclock to Asia/Calcutta Clock clockWithOtherZone = baseclock.withZone(zone); // print details of ZonedDateTime System.out.println("clockWithOtherZone Zone:" + clockWithOtherZone.getZone()); }} |
baseclock Zone:Etc/UTC clockWithOtherZone Zone:Asia/Calcutta
Reference:
https://docs.oracle.com/javase/8/docs/api/java/time/Clock.html#withZone-java.time.ZoneId-
