Class StandardZoneRules

  • All Implemented Interfaces:
    java.io.Serializable

    final class StandardZoneRules
    extends ZoneRules
    implements java.io.Serializable
    The rules describing how the zone offset varies through the year and historically.

    ZoneRules is immutable and thread-safe.

    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        A serialization identifier for this class.
        See Also:
        Constant Field Values
      • LAST_CACHED_YEAR

        private static final int LAST_CACHED_YEAR
        The last year to have its transitions cached.
        See Also:
        Constant Field Values
      • standardTransitions

        private final long[] standardTransitions
        The transitions between standard offsets (epoch seconds), sorted.
      • standardOffsets

        private final ZoneOffset[] standardOffsets
        The standard offsets.
      • savingsInstantTransitions

        private final long[] savingsInstantTransitions
        The transitions between instants (epoch seconds), sorted.
      • savingsLocalTransitions

        private final LocalDateTime[] savingsLocalTransitions
        The transitions between local date-times, sorted. This is a paired array, where the first entry is the start of the transition and the second entry is the end of the transition.
      • wallOffsets

        private final ZoneOffset[] wallOffsets
        The wall offsets.
      • lastRulesCache

        private final java.util.concurrent.ConcurrentMap<Year,​ZoneOffsetTransition[]> lastRulesCache
        The map of recent transitions.
    • Constructor Detail

      • StandardZoneRules

        StandardZoneRules​(ZoneOffset baseStandardOffset,
                          ZoneOffset baseWallOffset,
                          java.util.List<OffsetDateTime> standardOffsetTransitionList,
                          java.util.List<ZoneOffsetTransition> transitionList,
                          java.util.List<ZoneOffsetTransitionRule> lastRules)
        Constructor.
        Parameters:
        baseStandardOffset - the standard offset to use before legal rules were set, not null
        baseWallOffset - the wall offset to use before legal rules were set, not null
        standardOffsetTransitionList - the list of changes to the standard offset, not null
        transitionList - the list of transitions, not null
        lastRules - the recurring last rules, size 15 or less, not null
      • StandardZoneRules

        private StandardZoneRules​(long[] standardTransitions,
                                  ZoneOffset[] standardOffsets,
                                  long[] savingsInstantTransitions,
                                  ZoneOffset[] wallOffsets,
                                  ZoneOffsetTransitionRule[] lastRules)
        Constructor.
        Parameters:
        standardTransitions - the standard transitions, not null
        standardOffsets - the standard offsets, not null
        savingsLocalTransitions - the standard transitions, not null
        wallOffsets - the wall offsets, not null
        lastRules - the recurring last rules, size 15 or less, not null
    • Method Detail

      • writeReplace

        private java.lang.Object writeReplace()
        Uses a serialization delegate.
        Returns:
        the replacing object, never null
      • writeExternal

        void writeExternal​(java.io.DataOutput out)
                    throws java.io.IOException
        Writes the state to the stream.
        Parameters:
        out - the output stream, not null
        Throws:
        java.io.IOException - if an error occurs
      • readExternal

        static StandardZoneRules readExternal​(java.io.DataInput in)
                                       throws java.io.IOException,
                                              java.lang.ClassNotFoundException
        Reads the state from the stream.
        Parameters:
        in - the input stream, not null
        Returns:
        the created object, never null
        Throws:
        java.io.IOException - if an error occurs
        java.lang.ClassNotFoundException
      • getOffset

        public ZoneOffset getOffset​(InstantProvider instantProvider)
        Gets the offset applicable at the specified instant in this zone.

        For any given instant there can only ever be one valid offset, which is returned by this method. To access more detailed information about the offset at and around the instant use ZoneRules.getOffsetInfo(Instant).

        Specified by:
        getOffset in class ZoneRules
        Parameters:
        instantProvider - the instant to find the offset for, ignored for fixed offset rules, otherwise not null
        Returns:
        the offset, never null
      • getOffsetInfo

        public ZoneOffsetInfo getOffsetInfo​(LocalDateTime dt)
        Gets the offset information for a local date-time in this zone.

        This provides access to full details as to the offset or offsets applicable for the local date-time. The mapping from a local date-time to an offset is not straightforward. There are three cases:

        • Normal. Where there is a single offset for the local date-time.
        • Gap. Where there is a gap in the local time-line normally caused by the spring cutover to daylight savings. There are no valid offsets within the gap
        • Overlap. Where there is a gap in the local time-line normally caused by the autumn cutover from daylight savings. There are two valid offsets during the overlap.
        The returned object provides this information and it is vital to check ZoneOffsetInfo.isTransition() to handle the gap or overlap.
        Specified by:
        getOffsetInfo in class ZoneRules
        Parameters:
        dt - the date-time to find the offset information for, not null
        Returns:
        the offset information, never null
      • findOffsetInfo

        private ZoneOffsetInfo findOffsetInfo​(LocalDateTime dt,
                                              ZoneOffsetTransition trans)
        Finds the offset info for a local date-time and transition.
        Parameters:
        dt - the date-time, not null
        trans - the transition, not null
        Returns:
        the offset info, never null
      • findTransitionArray

        private ZoneOffsetTransition[] findTransitionArray​(int year)
        Finds the appropriate transition array for the given year.
        Parameters:
        year - the year, not null
        Returns:
        the transition array, never null
      • getStandardOffset

        public ZoneOffset getStandardOffset​(InstantProvider instantProvider)
        Gets the standard offset for the specified instant in this zone.

        This provides access to historic information on how the standard offset has changed over time. The standard offset is the offset before any daylight savings time is applied. This is typically the offset applicable during winter.

        Specified by:
        getStandardOffset in class ZoneRules
        Parameters:
        instantProvider - the instant to find the offset information for, not null
        Returns:
        the standard offset, never null
      • nextTransition

        public ZoneOffsetTransition nextTransition​(InstantProvider instantProvider)
        Gets the next transition after the specified transition.
        Specified by:
        nextTransition in class ZoneRules
        Parameters:
        instantProvider - the instant to get the next transition after, not null
        Returns:
        the next transition after the specified instant, null if this is after the last transition
      • previousTransition

        public ZoneOffsetTransition previousTransition​(InstantProvider instantProvider)
        Gets the previous transition after the specified transition.
        Specified by:
        previousTransition in class ZoneRules
        Parameters:
        instantProvider - the instant to get the previous transition after, not null
        Returns:
        the previous transition after the specified instant, null if this is before the first transition
      • getTransitions

        public java.util.List<ZoneOffsetTransition> getTransitions()
        Gets the complete list of transitions.

        This list normally contains a complete historical set of transitions that have occurred. Some transitions may be in the future, although generally the transition rules handle future years.

        Specified by:
        getTransitions in class ZoneRules
        Returns:
        independent, modifiable copy of the list of transitions, never null
      • getTransitionRules

        public java.util.List<ZoneOffsetTransitionRule> getTransitionRules()
        Gets the list of transition rules for years beyond those defined in the transition list.

        The list represents all the transitions that are expected in each year beyond those in the transition list. Normally, there are two transitions per year - into and out of daylight savings time. If daylight savings time does not occur then the list will be empty.

        Specified by:
        getTransitionRules in class ZoneRules
        Returns:
        independent, modifiable copy of the list of transition rules, never null
      • equals

        public boolean equals​(java.lang.Object otherRules)
        Checks if this object equals another, comparing the complete set of rules.

        The entire state of the object is compared.

        Specified by:
        equals in class ZoneRules
        Parameters:
        other - the other object to compare to, null returns false
        Returns:
        true if equal
      • hashCode

        public int hashCode()
        Returns a suitable hash code.
        Specified by:
        hashCode in class ZoneRules
        Returns:
        the hash code
      • toString

        public java.lang.String toString()
        Returns a string describing this object.
        Overrides:
        toString in class java.lang.Object
        Returns:
        a string for debugging, never null