Class ZoneOffset

java.lang.Object
javax.time.calendar.ZoneOffset
All Implemented Interfaces:
Serializable, Comparable<ZoneOffset>, Calendrical
public final class ZoneOffset extends Object implements Calendrical, Comparable<ZoneOffset>, Serializable
A time-zone offset from UTC, such as +02:00.

A time-zone offset is the period of time that a time-zone differs from UTC. This is usually a fixed number of hours and minutes.

Different parts of the world have different time-zone offsets. The rules for how offsets vary by place and time of year are captured in the TimeZone class.

For example, Paris is one hours ahead of UTC in winter and two hours ahead in summer. The TimeZone instance for Paris will reference two ZoneOffset instances - a +01:00 instance for winter, and a +02:00 instance for summer.

In 2008, time-zone offsets around the world extended from -12:00 to +14:00. To prevent any problems with that range being extended, yet still provide validation, the range of offsets is restricted to -18:00 to 18:00 inclusive.

This class is designed primarily for use with the ISOChronology. The fields of hours, minutes and seconds make assumptions that are valid for the standard ISO definitions of those fields. This class may be used with other calendar systems providing the definition of the time fields matches those of the ISO calendar system.

Instances of ZoneOffset must be compared using equals(Object). Implementations may choose to cache certain common offsets, however applications must not rely on such caching.

ZoneOffset is immutable and thread-safe.

Author:
Stephen Colebourne
See Also:

  • Field Details

    • UTC

      public static final ZoneOffset UTC
      The time-zone offset for UTC, with an id of 'Z'.

  • Method Details

    • of

      public static ZoneOffset of(String offsetID)
      Obtains an instance of ZoneOffset using the id.

      This method parses the string id of a ZoneOffset to return an instance. The parsing accepts all the formats generated by getID(), plus some additional formats:

      • Z - for UTC
      • +hh:mm
      • -hh:mm
      • +hhmm
      • -hhmm
      • +hh:mm:ss
      • -hh:mm:ss
      • +hhmmss
      • -hhmmss
      Note that ± means either the plus or minus symbol.

      The ID of the returned offset will be normalized to one of the formats described by getID().

      The maximum supported range is from +18:00 to -18:00 inclusive.

      Parameters:
      offsetID - the offset id, not null
      Returns:
      the ZoneOffset, never null
      Throws:
      IllegalArgumentException - if the offset id is invalid

    • ofHours

      public static ZoneOffset ofHours(int hours)
      Obtains an instance of ZoneOffset using an offset in hours.
      Parameters:
      hours - the time-zone offset in hours, from -18 to +18
      Returns:
      the ZoneOffset, never null
      Throws:
      IllegalArgumentException - if the offset is not in the required range

    • ofHoursMinutes

      public static ZoneOffset ofHoursMinutes(int hours, int minutes)
      Obtains an instance of ZoneOffset using an offset in hours and minutes.

      The sign of the hours and minutes components must match. Thus, if the hours is negative, the minutes must be negative or zero. If the hours is zero, the minutes may be positive, negative or zero.

      Parameters:
      hours - the time-zone offset in hours, from -18 to +18
      minutes - the time-zone offset in minutes, from 0 to ±59, sign matches hours
      Returns:
      the ZoneOffset, never null
      Throws:
      IllegalArgumentException - if the offset is not in the required range

    • ofHoursMinutesSeconds

      public static ZoneOffset ofHoursMinutesSeconds(int hours, int minutes, int seconds)
      Obtains an instance of ZoneOffset using an offset in hours, minutes and seconds.

      The sign of the hours, minutes and seconds components must match. Thus, if the hours is negative, the minutes and seconds must be negative or zero.

      Parameters:
      hours - the time-zone offset in hours, from -18 to +18
      minutes - the time-zone offset in minutes, from 0 to ±59, sign matches hours and seconds
      seconds - the time-zone offset in seconds, from 0 to ±59, sign matches hours and minutes
      Returns:
      the ZoneOffset, never null
      Throws:
      IllegalArgumentException - if the offset is not in the required range

    • of

      public static ZoneOffset of(PeriodProvider periodProvider)
      Obtains an instance of ZoneOffset from a period.

      This creates an offset from the specified period, converting using Period.of(PeriodProvider). Only the hour, minute and second fields from the period are used - other fields are ignored. The sign of the hours, minutes and seconds components must match. Thus, if the hours is negative, the minutes and seconds must be negative or zero.

      Parameters:
      periodProvider - the period to use, not null
      Returns:
      the ZoneOffset, never null
      Throws:
      CalendricalException - if the specified period cannot be converted to a Period
      IllegalArgumentException - if the offset is not in the required range

    • ofTotalSeconds

      public static ZoneOffset ofTotalSeconds(int totalSeconds)
      Obtains an instance of ZoneOffset specifying the total offset in seconds

      The offset must be in the range -18:00 to +18:00, which corresponds to -64800 to +64800.

      Parameters:
      totalSeconds - the total time-zone offset in seconds, from -64800 to +64800
      Returns:
      the ZoneOffset, never null
      Throws:
      IllegalArgumentException - if the offset is not in the required range

    • getAmountSeconds

      public int getAmountSeconds()
      Gets the total zone offset in seconds.

      This is the primary way to access the offset amount. It returns the total of the hours, minutes and seconds fields as a single offset that can be added to a time.

      Returns:
      the total zone offset amount in seconds

    • getID

      public String getID()
      Gets the normalized zone offset id.

      The id is minor variation to the standard ISO-8601 formatted string for the offset. There are three formats:

      • Z - for UTC (ISO-8601)
      • +hh:mm or -hh:mm - if the seconds are zero (ISO-8601)
      • +hh:mm:ss or -hh:mm:ss - if the seconds are non-zero (not ISO-8601)
      Returns:
      the zone offset ID, never null

    • getHoursField

      public int getHoursField()
      Gets the hours field of the zone offset.

      This method only has meaning when considered with the minutes and seconds fields. Most applications are advised to use toPeriod() or getAmountSeconds().

      The zone offset is divided into three fields - hours, minutes and seconds. This method returns the value of the hours field. The sign of the value returned by this method will match that of the minutes and seconds fields.

      Returns:
      the hours field of the zone offset amount, from -18 to 18

    • getMinutesField

      public int getMinutesField()
      Gets the minutes field of the zone offset.

      This method only has meaning when considered with the hours and minutes fields. Most applications are advised to use toPeriod() or getAmountSeconds().

      The zone offset is divided into three fields - hours, minutes and seconds. This method returns the value of the minutes field. The sign of the value returned by this method will match that of the hours and seconds fields.

      Returns:
      the minutes field of the zone offset amount, from -59 to 59 where the sign matches the hours and seconds

    • getSecondsField

      public int getSecondsField()
      Gets the seconds field of the zone offset.

      This method only has meaning when considered with the hours and minutes fields. Most applications are advised to use toPeriod() or getAmountSeconds().

      The zone offset is divided into three fields - hours, minutes and seconds. This method returns the value of the seconds field. The sign of the value returned by this method will match that of the hours and minutes fields.

      Returns:
      the seconds field of the zone offset amount, from -59 to 59 where the sign matches the hours and minutes

    • plus

      public ZoneOffset plus(PeriodProvider periodProvider)
      Returns a copy of this offset with the specified period added.

      This adds the amount in hours, minutes and seconds from the specified period to this offset. This converts the period using Period.of(PeriodProvider). Only the hour, minute and second fields from the period are used - other fields are ignored.

      This instance is immutable and unaffected by this method call.

      Parameters:
      periodProvider - the period to add, not null
      Returns:
      a ZoneOffset based on this offset with the period added, never null
      Throws:
      CalendricalException - if the specified period cannot be converted to a Period
      IllegalArgumentException - if the offset is not in the required range

    • toPeriod

      public Period toPeriod()
      Converts this offset to a period.

      The period returned will have fields for hour, minute and second. For negative offsets, the values in the period will all be negative.

      For example, +02:45 will be converted to P2H45M, while -01:15 will be converted to P-1H-15M.

      Returns:
      the period equivalent to the zone offset amount, never null

    • toTimeZone

      public TimeZone toTimeZone()
      Converts this offset to a time-zone.

      The returned time-zone will use this offset for all instants.

      Returns:
      the time-zone, never null

    • compareTo

      public int compareTo(ZoneOffset other)
      Compares this offset to another offset in descending order.

      The offsets are compared in the order that they occur for the same time of day around the world. Thus, an offset of +10:00 comes before an offset of +09:00 and so on down to -18:00.

      Specified by:
      compareTo in interface Comparable<ZoneOffset>
      Parameters:
      other - the other date to compare to, not null
      Returns:
      the comparator value, negative if less, postive if greater
      Throws:
      NullPointerException - if other is null

    • equals

      public boolean equals(Object other)
      Checks if this instance is equal to the specified offset, comparing the amount of the offset in seconds.
      Overrides:
      equals in class Object
      Parameters:
      other - the other zone offset, null returns false
      Returns:
      true if this offset is the same as that specified

    • hashCode

      public int hashCode()
      A hash code for the zone offset.
      Overrides:
      hashCode in class Object
      Returns:
      a suitable hash code

    • toString

      public String toString()
      Returns a string representation of the zone offset, which is the same as the normalized id.
      Overrides:
      toString in class Object
      Returns:
      the id

    • get

      public <T> T get(CalendricalRule<T> rule)
      Gets the value of the specified calendrical rule.

      This method queries the value of the specified calendrical rule. If the value cannot be returned for the rule from this offset then null will be returned.

      Specified by:
      get in interface Calendrical
      Parameters:
      rule - the rule to use, not null
      Returns:
      the value for the rule, null if the value cannot be returned

    • rule

      public static CalendricalRule<ZoneOffset> rule()
      Gets the rule for the zone-offset.
      Returns:
      the rule for the zone-offset, never null