Module java.base
Package java.time.zone

Class ZoneOffsetTransitionRule

java.lang.Object
java.time.zone.ZoneOffsetTransitionRule
All Implemented Interfaces:
Serializable
public final class ZoneOffsetTransitionRule extends Object implements Serializable
A rule expressing how to create a transition.

This class allows rules for identifying future transitions to be expressed. A rule might be written in many forms:

  • the 16th March
  • the Sunday on or after the 16th March
  • the Sunday on or before the 16th March
  • the last Sunday in February
These different rule types can be expressed and queried.
Implementation Requirements:
This class is immutable and thread-safe.
Since:
1.8
See Also:
Serialized Form

  • Method Details

    • of

      public static ZoneOffsetTransitionRule of​(Month month, int dayOfMonthIndicator, DayOfWeek dayOfWeek, LocalTime time, boolean timeEndOfDay, ZoneOffsetTransitionRule.TimeDefinition timeDefinition, ZoneOffset standardOffset, ZoneOffset offsetBefore, ZoneOffset offsetAfter)
      Obtains an instance defining the yearly rule to create transitions between two offsets.

      Applications should normally obtain an instance from ZoneRules. This factory is only intended for use when creating ZoneRules.

      Parameters:
      month - the month of the month-day of the first day of the cutover week, not null
      dayOfMonthIndicator - the day of the month-day of the cutover week, positive if the week is that day or later, negative if the week is that day or earlier, counting from the last day of the month, from -28 to 31 excluding 0
      dayOfWeek - the required day-of-week, null if the month-day should not be changed
      time - the cutover time in the 'before' offset, not null
      timeEndOfDay - whether the time is midnight at the end of day
      timeDefinition - how to interpret the cutover
      standardOffset - the standard offset in force at the cutover, not null
      offsetBefore - the offset before the cutover, not null
      offsetAfter - the offset after the cutover, not null
      Returns:
      the rule, not null
      Throws:
      IllegalArgumentException - if the day of month indicator is invalid
      IllegalArgumentException - if the end of day flag is true when the time is not midnight
      IllegalArgumentException - if time.getNano() returns non-zero value

    • getMonth

      public Month getMonth()
      Gets the month of the transition.

      If the rule defines an exact date then the month is the month of that date.

      If the rule defines a week where the transition might occur, then the month if the month of either the earliest or latest possible date of the cutover.

      Returns:
      the month of the transition, not null

    • getDayOfMonthIndicator

      public int getDayOfMonthIndicator()
      Gets the indicator of the day-of-month of the transition.

      If the rule defines an exact date then the day is the month of that date.

      If the rule defines a week where the transition might occur, then the day defines either the start of the end of the transition week.

      If the value is positive, then it represents a normal day-of-month, and is the earliest possible date that the transition can be. The date may refer to 29th February which should be treated as 1st March in non-leap years.

      If the value is negative, then it represents the number of days back from the end of the month where -1 is the last day of the month. In this case, the day identified is the latest possible date that the transition can be.

      Returns:
      the day-of-month indicator, from -28 to 31 excluding 0

    • getDayOfWeek

      public DayOfWeek getDayOfWeek()
      Gets the day-of-week of the transition.

      If the rule defines an exact date then this returns null.

      If the rule defines a week where the cutover might occur, then this method returns the day-of-week that the month-day will be adjusted to. If the day is positive then the adjustment is later. If the day is negative then the adjustment is earlier.

      Returns:
      the day-of-week that the transition occurs, null if the rule defines an exact date

    • getLocalTime

      public LocalTime getLocalTime()
      Gets the local time of day of the transition which must be checked with isMidnightEndOfDay().

      The time is converted into an instant using the time definition.

      Returns:
      the local time of day of the transition, not null

    • isMidnightEndOfDay

      public boolean isMidnightEndOfDay()
      Is the transition local time midnight at the end of day.

      The transition may be represented as occurring at 24:00.

      Returns:
      whether a local time of midnight is at the start or end of the day

    • getTimeDefinition

      public ZoneOffsetTransitionRule.TimeDefinition getTimeDefinition()
      Gets the time definition, specifying how to convert the time to an instant.

      The local time can be converted to an instant using the standard offset, the wall offset or UTC.

      Returns:
      the time definition, not null

    • getStandardOffset

      public ZoneOffset getStandardOffset()
      Gets the standard offset in force at the transition.
      Returns:
      the standard offset, not null

    • getOffsetBefore

      public ZoneOffset getOffsetBefore()
      Gets the offset before the transition.
      Returns:
      the offset before, not null

    • getOffsetAfter

      public ZoneOffset getOffsetAfter()
      Gets the offset after the transition.
      Returns:
      the offset after, not null

    • createTransition

      public ZoneOffsetTransition createTransition​(int year)
      Creates a transition instance for the specified year.

      Calculations are performed using the ISO-8601 chronology.

      Parameters:
      year - the year to create a transition for, not null
      Returns:
      the transition instance, not null

    • equals

      public boolean equals​(Object otherRule)
      Checks if this object equals another.

      The entire state of the object is compared.

      Overrides:
      equals in class Object
      Parameters:
      otherRule - the other object to compare to, null returns false
      Returns:
      true if equal
      See Also:
      Object.hashCode(), HashMap

    • hashCode

      public int hashCode()
      Returns a suitable hash code.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code
      See Also:
      Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

    • toString

      public String toString()
      Returns a string describing this object.
      Overrides:
      toString in class Object
      Returns:
      a string for debugging, not null