TimeAxis (Time4J-Core 4.33 API)

java.lang.Object
- net.time4j.engine.Chronology<T>
- - net.time4j.engine.TimeAxis<U,T>

Type Parameters:

U - generic type of time units

T - generic type of time context compatible to TimePoint

All Implemented Interfaces:

Comparator<T>, ChronoMerger<T>, TimeLine<T>
```
public final class TimeAxis<U,T extends TimePoint<U,T>>
extends Chronology<T>
implements TimeLine<T>
```
A time axis is a dynamic view on a chronology where a system of registered time units is used to define a time arithmetic for any time points belonging to this time axis respective chronology.

Author:

Meno Hochschild

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`TimeAxis.Builder<U,T extends TimePoint<U,T>>` Creates a builder for a new time axis respective chronology and will only be used during loading a class of type `TimePoint (T)` in a static initializer.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`int`	`compare(T first, T second)` Compares points in time by their temporal position on the timeline.
`T`	`createFrom(ChronoEntity<?> entity, AttributeQuery attributes, boolean preparsing)` Deprecated.
`T`	`createFrom(ChronoEntity<?> entity, AttributeQuery attributes, boolean lenient, boolean preparsing)` Creates a new entity of type T based on given chronological data.
`ChronoElement<T>`	`element()` Yields this time axis as chronological self-referencing element.
`U`	`getBaseUnit(ChronoElement<?> element)` Returns the base unit of given element if available.
`CalendarSystem<T>`	`getCalendarSystem()` Returns the associated calendar system if available.
`CalendarSystem<T>`	`getCalendarSystem(String variant)` Returns the calendar system for given calendar variant if available.
`double`	`getLength(U unit)` Returns the length of given time unit in seconds as it is usual or estimated on this time axis.
`T`	`getMaximum()` Yields the maximum of this time axis.
`T`	`getMinimum()` Yields the minimum of this time axis.
`Set<U>`	`getRegisteredUnits()` Returns all registered time units.
`Class<U>`	`getUnitType()` Returns the type of supported time units.
`boolean`	`hasBaseUnit(ChronoElement<?> element)` Queries if given element has a base unit.
`boolean`	`hasCalendarSystem()` Queries if this chronology has a calendar system.
`boolean`	`isCalendrical()` Determines if this timeline is calendrical or not.
`boolean`	`isConvertible(U unit1, U unit2)` Queries if given time units are convertible.
`boolean`	`isRegistered(U unit)` Queries if given time unit is registered.
`boolean`	`isSupported(U unit)` Queries if given time unit is supported.
`T`	`stepBackwards(T timepoint)` Move given point in time backwards by one step.
`T`	`stepForward(T timepoint)` Move given point in time forward by one step.
`Comparator<? super U>`	`unitComparator()` Compares time units by ascending precision (that is descending length).

Methods inherited from class net.time4j.engine.Chronology
createFrom, createFrom, getChronoType, getDefaultPivotYear, getDefaultStartOfDay, getExtensions, getFormatPattern, getRegisteredElements, isRegistered, isSupported, lookup, preformat, preparser

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator
comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

- Method Detail
  - getUnitType
```
public Class<U> getUnitType()
```
    Returns the type of supported time units.
    
    Returns:
    
    reified type of time unit
  - getRegisteredUnits
```
public Set<U> getRegisteredUnits()
```
    Returns all registered time units.
    
    Returns:
    
    unmodifiable set of registered units without duplicates
  - isRegistered
```
public boolean isRegistered(U unit)
```
    Queries if given time unit is registered.
    
    Parameters:
    
    unit - time unit (optional)
    
    Returns:
    
    true if registered else false
  - isSupported
```
public boolean isSupported(U unit)
```
    Queries if given time unit is supported.
    
    A time unit is supported if it is either registered or if it defines a suitable rule.
    
    Parameters:
    
    unit - time unit (optional)
    
    Returns:
    
    true if supported else false
    
    See Also:
    
    BasicUnit.derive(Chronology)
  - getLength
```
public double getLength(U unit)
```
    Returns the length of given time unit in seconds as it is usual or estimated on this time axis.
    
    Example: In ISO-systems the year has 365.2425 * 86400 seconds by default (mean average), in a julian calender 365.25 * 86400 seconds however. Daylight-saving-transitions or UTC-leapseconds are not counted here.
    
    Note: If given time unit is not registered then Time4J tries to interprete the unit as ChronoUnit. If this fails, too, then the length is not calculatable.
    
    Parameters:
    
    unit - time unit
    
    Returns:
    
    estimated standard length in seconds or Double.NaN if not calculatable
    
    See Also:
    
    ChronoUnit
  - isConvertible
```
public boolean isConvertible(U unit1,
                             U unit2)
```
    Queries if given time units are convertible.
    
    Convertibility means that there exists a fixed integer factor for conversion between the units. Examples for convertible units are weeks/days (factor 7) or years/months (factor 12) in ISO-systems. Otherwise minutes and seconds will only be convertible with factor 60 if there is no UTC-context with possible leap seconds.
    
    If two time units are convertible then the length of a time unit (getLength()) can be used to convert time units by applying the rounded quotient of lengths of units.
    
    Parameters:
    
    unit1 - first time unit
    
    unit2 - second time unit
    
    Returns:
    
    true if convertible else false
    
    See Also:
    
    getLength(U)
  - hasBaseUnit
```
public boolean hasBaseUnit(ChronoElement<?> element)
```
    Queries if given element has a base unit.
    
    Parameters:
    
    element - chronological element (optional)
    
    Returns:
    
    true if given element has a base unit else false
    
    See Also:
    
    getBaseUnit(ChronoElement)
  - getBaseUnit
```
public U getBaseUnit(ChronoElement<?> element)
```
    Returns the base unit of given element if available.
    
    Only registred elements can have a base unit unless the element is a BasicElement and refers another registered element with a base unit.
    
    Parameters:
    
    element - chronological element
    
    Returns:
    
    found base unit
    
    Throws:
    
    ChronoException - if there is no base unit
    
    See Also:
    
    hasBaseUnit(ChronoElement), BasicElement.getParent()
  - unitComparator
```
public Comparator<? super U> unitComparator()
```
    Compares time units by ascending precision (that is descending length).
    
    Note: Before release v4.21, the time axis implemented Comparator<U>, not Comparator<T>. This new method serves as the replacement for the old comparator method.
    
    Returns:
    
    Comparator
    
    Since:
    
    3.25/4.21
    
    See Also:
    
    compare(TimePoint, TimePoint)
  - compare
```
public int compare(T first,
                   T second)
```
    Compares points in time by their temporal position on the timeline.
    
    Specified by:
    
    compare in interface Comparator<T extends TimePoint<U,T>>
    
    Parameters:
    
    first - the first point in comparison
    
    second - the second point in comparison
    
    Returns:
    
    positive, zero or negative number if first is later, simultaneous or earlier than second
    
    Since:
    
    3.25/4.21
  - getMinimum
```
public T getMinimum()
```
    Yields the minimum of this time axis.
    
    Specified by:
    
    getMinimum in interface TimeLine<T extends TimePoint<U,T>>
    
    Returns:
    
    earliest possible time point
  - getMaximum
```
public T getMaximum()
```
    Yields the maximum of this time axis.
    
    Specified by:
    
    getMaximum in interface TimeLine<T extends TimePoint<U,T>>
    
    Returns:
    
    latest possible time point
  - isCalendrical
```
public boolean isCalendrical()
```
    Description copied from interface: TimeLine
    
    Determines if this timeline is calendrical or not.
    
    Specified by:
    
    isCalendrical in interface TimeLine<T extends TimePoint<U,T>>
    
    Returns:
    
    boolean
    
    See Also:
    
    CalendarDate
  - hasCalendarSystem
```
public boolean hasCalendarSystem()
```
    Description copied from class: Chronology
    
    Queries if this chronology has a calendar system.
    
    Overrides:
    
    hasCalendarSystem in class Chronology<T extends TimePoint<U,T>>
    
    Returns:
    
    true if this chronology has a calendar system else false
    
    See Also:
    
    Chronology.getCalendarSystem()
  - getCalendarSystem
```
public CalendarSystem<T> getCalendarSystem()
```
    Description copied from class: Chronology
    
    Returns the associated calendar system if available.
    
    Overrides:
    
    getCalendarSystem in class Chronology<T extends TimePoint<U,T>>
    
    Returns:
    
    calendar system, not null
    
    See Also:
    
    Chronology.hasCalendarSystem()
  - getCalendarSystem
```
public CalendarSystem<T> getCalendarSystem(String variant)
```
    Description copied from class: Chronology
    
    Returns the calendar system for given calendar variant if available.
    
    Overrides:
    
    getCalendarSystem in class Chronology<T extends TimePoint<U,T>>
    
    Parameters:
    
    variant - name of calendar variant
    
    Returns:
    
    calendar system, not null
    
    See Also:
    
    CalendarVariant.getVariant()
  - createFrom
```
@Deprecated
public T createFrom(ChronoEntity<?> entity,
                                 AttributeQuery attributes,
                                 boolean preparsing)
```
    Deprecated.
    
    Description copied from interface: ChronoMerger
    
    Creates a new entity of type T based on given chronological data.
    
    Typically the method will query the given entity with different priorities for elements which can compose a new chronological entity (per group). For example a calendar date can be composed either by epoch days or the group (year)-(month)-(day-of-month) or the group (year)-(day-of-year) etc.
    
    A text parser will call this method after having resolved a text into single chronological elements and values. Implementations should always validate the parsed values. In case of error, they are free to either throw an IllegalArgumentException or to generate and to save an error message by mean of the expression entity.with(ValidationElement.ERROR_MESSAGE, message.
    
    Specified by:
    
    createFrom in interface ChronoMerger<T extends TimePoint<U,T>>
    
    Overrides:
    
    createFrom in class Chronology<T extends TimePoint<U,T>>
    
    Parameters:
    
    entity - any chronological entity like parsed elements with their values
    
    attributes - configuration attributes given by parser
    
    preparsing - preparsing phase active?
    
    Returns:
    
    new time context or null if given data are insufficient
    
    See Also:
    
    ValidationElement.ERROR_MESSAGE
  - createFrom
```
public T createFrom(ChronoEntity<?> entity,
                    AttributeQuery attributes,
                    boolean lenient,
                    boolean preparsing)
```
    Description copied from interface: ChronoMerger
    
    Creates a new entity of type T based on given chronological data.
    
    Typically the method will query the given entity with different priorities for elements which can compose a new chronological entity (per group). For example a calendar date can be composed either by epoch days or the group (year)-(month)-(day-of-month) or the group (year)-(day-of-year) etc.
    
    A text parser will call this method after having resolved a text into single chronological elements and values. Implementations should always validate the parsed values. In case of error, they are free to either throw an IllegalArgumentException or to generate and to save an error message by mean of the expression entity.with(ValidationElement.ERROR_MESSAGE, message.
    
    Specified by:
    
    createFrom in interface ChronoMerger<T extends TimePoint<U,T>>
    
    Overrides:
    
    createFrom in class Chronology<T extends TimePoint<U,T>>
    
    Parameters:
    
    entity - any chronological entity like parsed elements with their values
    
    attributes - configuration attributes given by parser
    
    lenient - controls the leniency how to interprete invalid values
    
    preparsing - preparsing phase active?
    
    Returns:
    
    new time context or null if given data are insufficient
    
    See Also:
    
    ValidationElement.ERROR_MESSAGE
  - element
```
public ChronoElement<T> element()
```
    Yields this time axis as chronological self-referencing element.
    
    Returns:
    
    self-referencing element
  - stepForward
```
public T stepForward(T timepoint)
```
    Description copied from interface: TimeLine
    
    Move given point in time forward by one step.
    
    Specified by:
    
    stepForward in interface TimeLine<T extends TimePoint<U,T>>
    
    Parameters:
    
    timepoint - point in time to be moved forward
    
    Returns:
    
    new point in time one step after given argument or null if applied on the maximum of timeline
  - stepBackwards
```
public T stepBackwards(T timepoint)
```
    Description copied from interface: TimeLine
    
    Move given point in time backwards by one step.
    
    Specified by:
    
    stepBackwards in interface TimeLine<T extends TimePoint<U,T>>
    
    Parameters:
    
    timepoint - point in time to be moved backwards
    
    Returns:
    
    new point in time one step before given argument or null if applied on the minimum of timeline

Class TimeAxis<U,T extends TimePoint<U,T>>

Nested Class Summary

Method Summary

Methods inherited from class net.time4j.engine.Chronology

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Comparator

Method Detail

getUnitType

getRegisteredUnits

isRegistered

isSupported

getLength

isConvertible

hasBaseUnit

getBaseUnit

unitComparator

compare

getMinimum

getMaximum

isCalendrical

hasCalendarSystem

getCalendarSystem

getCalendarSystem

createFrom

createFrom

element

stepForward

stepBackwards