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(java.lang.Object). Implementations may choose to cache certain common offsets, however applications must not rely on such caching.

ZoneOffset is immutable and thread-safe.

See Also:
  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    (package private) static final class 
    Rule implementation.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final int
    The offset in seconds.
    private static final ReadWriteLock
    Cache of time-zone offset by offset in seconds.
    private final String
    The string form of the time-zone offset.
    private static final Map<String,ZoneOffset>
    Cache of time-zone offset by id.
    private static final int
    The number of minutes per hour.
    private static final Map<Integer,ZoneOffset>
    Cache of time-zone offset by offset in seconds.
    private static final int
    The number of seconds per hour.
    private static final int
    The number of seconds per minute.
    private static final long
    A serialization identifier for this class.
    static final ZoneOffset
    The time-zone offset for UTC, with an id of 'Z'.
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    private
    ZoneOffset(int totalSeconds)
    Constructor.
  • Method Summary

    Modifier and Type
    Method
    Description
    int
    Compares this offset to another offset in descending order.
    boolean
    equals(Object other)
    Checks if this instance is equal to the specified offset, comparing the amount of the offset in seconds.
    <T> T
    Gets the value of the specified calendrical rule.
    int
    Gets the total zone offset in seconds.
    int
    Gets the hours field of the zone offset.
    Gets the normalized zone offset id.
    int
    Gets the minutes field of the zone offset.
    int
    Gets the seconds field of the zone offset.
    int
    A hash code for the zone offset.
    static ZoneOffset
    of(String offsetID)
    Obtains an instance of ZoneOffset using the id.
    static ZoneOffset
    of(PeriodProvider periodProvider)
    Obtains an instance of ZoneOffset from a period.
    static ZoneOffset
    ofHours(int hours)
    Obtains an instance of ZoneOffset using an offset in hours.
    static ZoneOffset
    ofHoursMinutes(int hours, int minutes)
    Obtains an instance of ZoneOffset using an offset in hours and minutes.
    static ZoneOffset
    ofHoursMinutesSeconds(int hours, int minutes, int seconds)
    Obtains an instance of ZoneOffset using an offset in hours, minutes and seconds.
    static ZoneOffset
    ofTotalSeconds(int totalSeconds)
    Obtains an instance of ZoneOffset specifying the total offset in seconds
    private static int
    parseNumber(String offsetID, int pos, boolean precededByColon)
    Parse a two digit zero-prefixed number.
    plus(PeriodProvider periodProvider)
    Returns a copy of this offset with the specified period added.
    private Object
    Resolves singletons.
    Gets the rule for the zone-offset.
    Converts this offset to a period.
    Returns a string representation of the zone offset, which is the same as the normalized id.
    private static int
    totalSeconds(int hours, int minutes, int seconds)
    Calculates the total offset in seconds.
    Converts this offset to a time-zone.
    private static void
    validate(int hours, int minutes, int seconds)
    Validates the offset fields.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait
  • Field Details

    • CACHE_LOCK

      private static final ReadWriteLock CACHE_LOCK
      Cache of time-zone offset by offset in seconds.
    • SECONDS_CACHE

      private static final Map<Integer,ZoneOffset> SECONDS_CACHE
      Cache of time-zone offset by offset in seconds.
    • ID_CACHE

      private static final Map<String,ZoneOffset> ID_CACHE
      Cache of time-zone offset by id.
    • UTC

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

      private static final int SECONDS_PER_HOUR
      The number of seconds per hour.
      See Also:
    • SECONDS_PER_MINUTE

      private static final int SECONDS_PER_MINUTE
      The number of seconds per minute.
      See Also:
    • MINUTES_PER_HOUR

      private static final int MINUTES_PER_HOUR
      The number of minutes per hour.
      See Also:
    • serialVersionUID

      private static final long serialVersionUID
      A serialization identifier for this class.
      See Also:
    • amountSeconds

      private final int amountSeconds
      The offset in seconds.
    • id

      private final transient String id
      The string form of the time-zone offset.
  • Constructor Details

    • ZoneOffset

      private ZoneOffset(int totalSeconds)
      Constructor.
      Parameters:
      totalSeconds - the total time-zone offset in seconds, from -64800 to +64800
  • 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
    • parseNumber

      private static int parseNumber(String offsetID, int pos, boolean precededByColon)
      Parse a two digit zero-prefixed number.
      Parameters:
      offsetID - the offset id, not null
      pos - the position to parse, valid
      precededByColon - should this number be prefixed by a precededByColon
      Returns:
      the parsed number, from 0 to 99
    • 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
    • validate

      private static void validate(int hours, int minutes, int seconds)
      Validates the offset fields.
      Parameters:
      hours - the time-zone offset in hours, from -18 to +18
      minutes - the time-zone offset in minutes, from 0 to ±59
      seconds - the time-zone offset in seconds, from 0 to ±59
      Throws:
      IllegalArgumentException - if the offset is not in the required range
    • totalSeconds

      private static int totalSeconds(int hours, int minutes, int seconds)
      Calculates the total offset in seconds.
      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 total in seconds
    • 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
    • readResolve

      private Object readResolve()
      Resolves singletons.
      Returns:
      the singleton instance
    • 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