ZoneOffsetTransition

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public final class ZoneOffsetTransition extends Object
implements Comparable<ZoneOffsetTransition> Serializable

A transition between two offsets caused by a discontinuity in the local time-line.

A transition between two offsets is normally the result of a daylight savings cutover. The discontinuity is normally a gap in spring and an overlap in autumn. ZoneOffsetTransition models the transition between the two offsets.

Gaps occur where there are local date-times that simply do not exist. An example would be when the offset changes from +03:00 to +04:00. This might be described as 'the clocks will move forward one hour tonight at 1am'.

Overlaps occur where there are local date-times that exist twice. An example would be when the offset changes from +04:00 to +03:00. This might be described as 'the clocks will move back one hour tonight at 2am'.

Public Method Summary

int
compareTo(ZoneOffsetTransition transition)
Compares this transition to another based on the transition instant.
boolean
equals(Object other)
Checks if this object equals another.
LocalDateTime
getDateTimeAfter()
Gets the local transition date-time, as would be expressed with the 'after' offset.
LocalDateTime
getDateTimeBefore()
Gets the local transition date-time, as would be expressed with the 'before' offset.
Duration
getDuration()
Gets the duration of the transition.
Instant
getInstant()
Gets the transition instant.
ZoneOffset
getOffsetAfter()
Gets the offset after the transition.
ZoneOffset
getOffsetBefore()
Gets the offset before the transition.
int
hashCode()
Returns a suitable hash code.
boolean
isGap()
Does this transition represent a gap in the local time-line.
boolean
isOverlap()
Does this transition represent an overlap in the local time-line.
boolean
isValidOffset(ZoneOffset offset)
Checks if the specified offset is valid during this transition.
static ZoneOffsetTransition
of(LocalDateTime transition, ZoneOffset offsetBefore, ZoneOffset offsetAfter)
Obtains an instance defining a transition between two offsets.
long
toEpochSecond()
Gets the transition instant as an epoch second.
String
toString()
Returns a string describing this object.

Inherited Method Summary

Public Methods

public int compareTo (ZoneOffsetTransition transition)

Compares this transition to another based on the transition instant.

This compares the instants of each transition. The offsets are ignored, making this order inconsistent with equals.

Parameters
transition the transition to compare to, not null
Returns
  • the comparator value, negative if less, positive if greater

public boolean equals (Object other)

Checks if this object equals another.

The entire state of the object is compared.

Parameters
other the other object to compare to, null returns false
Returns
  • true if equal

public LocalDateTime getDateTimeAfter ()

Gets the local transition date-time, as would be expressed with the 'after' offset.

This is the first date-time after the discontinuity, when the new offset applies.

The combination of the 'before' date-time and offset represents the same instant as the 'after' date-time and offset.

Returns
  • the transition date-time expressed with the after offset, not null

public LocalDateTime getDateTimeBefore ()

Gets the local transition date-time, as would be expressed with the 'before' offset.

This is the date-time where the discontinuity begins expressed with the 'before' offset. At this instant, the 'after' offset is actually used, therefore the combination of this date-time and the 'before' offset will never occur.

The combination of the 'before' date-time and offset represents the same instant as the 'after' date-time and offset.

Returns
  • the transition date-time expressed with the before offset, not null

public Duration getDuration ()

Gets the duration of the transition.

In most cases, the transition duration is one hour, however this is not always the case. The duration will be positive for a gap and negative for an overlap. Time-zones are second-based, so the nanosecond part of the duration will be zero.

Returns
  • the duration of the transition, positive for gaps, negative for overlaps

public Instant getInstant ()

Gets the transition instant.

This is the instant of the discontinuity, which is defined as the first instant that the 'after' offset applies.

The methods getInstant(), getDateTimeBefore() and getDateTimeAfter() all represent the same instant.

Returns
  • the transition instant, not null

public ZoneOffset getOffsetAfter ()

Gets the offset after the transition.

This is the offset in use on and after the instant of the transition.

Returns
  • the offset after the transition, not null

public ZoneOffset getOffsetBefore ()

Gets the offset before the transition.

This is the offset in use before the instant of the transition.

Returns
  • the offset before the transition, not null

public int hashCode ()

Returns a suitable hash code.

Returns
  • the hash code

public boolean isGap ()

Does this transition represent a gap in the local time-line.

Gaps occur where there are local date-times that simply do not exist. An example would be when the offset changes from +01:00 to +02:00. This might be described as 'the clocks will move forward one hour tonight at 1am'.

Returns
  • true if this transition is a gap, false if it is an overlap

public boolean isOverlap ()

Does this transition represent an overlap in the local time-line.

Overlaps occur where there are local date-times that exist twice. An example would be when the offset changes from +02:00 to +01:00. This might be described as 'the clocks will move back one hour tonight at 2am'.

Returns
  • true if this transition is an overlap, false if it is a gap

public boolean isValidOffset (ZoneOffset offset)

Checks if the specified offset is valid during this transition.

This checks to see if the given offset will be valid at some point in the transition. A gap will always return false. An overlap will return true if the offset is either the before or after offset.

Parameters
offset the offset to check, null returns false
Returns
  • true if the offset is valid during the transition

public static ZoneOffsetTransition of (LocalDateTime transition, ZoneOffset offsetBefore, ZoneOffset offsetAfter)

Obtains an instance defining a transition between two offsets.

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

Parameters
transition the transition date-time at the transition, which never actually occurs, expressed local to the before offset, not null
offsetBefore the offset before the transition, not null
offsetAfter the offset at and after the transition, not null
Returns
  • the transition, not null
Throws
IllegalArgumentException if offsetBefore and offsetAfter are equal, or transition.getNano() returns non-zero value

public long toEpochSecond ()

Gets the transition instant as an epoch second.

Returns
  • the transition epoch second

public String toString ()

Returns a string describing this object.

Returns
  • a string for debugging, not null