org.joda.time
Interface ReadableInstant

All Superinterfaces:

Comparable

All Known Subinterfaces:

ReadableDateTime, ReadWritableDateTime, ReadWritableInstant

All Known Implementing Classes:

AbstractDateTime, AbstractInstant, BaseDateTime, DateMidnight, DateTime, Instant, MutableDateTime

public interface ReadableInstant

extends Comparable

Defines an instant in the datetime continuum. This interface expresses the datetime as milliseconds from 1970-01-01T00:00:00Z.

The implementation of this interface may be mutable or immutable. This interface only gives access to retrieve data, never to change it.

Methods in your application should be defined using ReadableInstant as a parameter if the method only wants to read the instant without needing to know the specific datetime fields.

Since:

1.0

Author:

Stephen Colebourne

Method Summary

int	compareTo(Object readableInstant) Compares this object with the specified object for ascending millisecond instant order.
boolean	equals(Object readableInstant) Compares this object with the specified object for equality based on the millisecond instant and the Chronology.
int	get(DateTimeFieldType type) Get the value of one of the fields of a datetime.
Chronology	getChronology() Gets the chronology of the instant.
long	getMillis() Get the value as the number of milliseconds since the epoch, 1970-01-01T00:00:00Z.
DateTimeZone	getZone() Gets the time zone of the instant from the chronology.
int	hashCode() Gets a hash code for the instant that is compatible with the equals method.
boolean	isAfter(ReadableInstant instant) Is this instant after the instant passed in comparing solely by millisecond.
boolean	isBefore(ReadableInstant instant) Is this instant before the instant passed in comparing solely by millisecond.
boolean	isEqual(ReadableInstant instant) Is this instant equal to the instant passed in comparing solely by millisecond.
boolean	isSupported(DateTimeFieldType field) Checks whether the field type specified is supported by this implementation.
Instant	toInstant() Get the value as a simple immutable Instant object.
String	toString() Get the value as a String in a recognisable ISO8601 format.

Method Detail

getMillis

public long getMillis()

Get the value as the number of milliseconds since the epoch, 1970-01-01T00:00:00Z.

Returns:

the value as milliseconds

getChronology

public Chronology getChronology()

Gets the chronology of the instant.

The Chronology provides conversion from the millisecond value to meaningful fields in a particular calendar system.

Returns:

the Chronology, never null

getZone

public DateTimeZone getZone()

Gets the time zone of the instant from the chronology.

Returns:

the DateTimeZone that the instant is using, never null

get

public int get(DateTimeFieldType type)

Get the value of one of the fields of a datetime.

This method uses the chronology of the instant to obtain the value.

Parameters:

type - a field type, usually obtained from DateTimeFieldType, not null

Returns:

the value of that field

Throws:

IllegalArgumentException - if the field type is null

isSupported

public boolean isSupported(DateTimeFieldType field)

Checks whether the field type specified is supported by this implementation.

Parameters:

field - the field type to check, may be null which returns false

Returns:

true if the field is supported

toInstant

public Instant toInstant()

Get the value as a simple immutable Instant object.

This can be useful if you don't trust the implementation of the interface to be well-behaved, or to get a guaranteed immutable object.

Returns:

the value as an Instant object

compareTo

public int compareTo(Object readableInstant)

Compares this object with the specified object for ascending millisecond instant order. This ordering is inconsistent with equals, as it ignores the Chronology.

All ReadableInstant instances are accepted.

Specified by:

compareTo in interface Comparable

Parameters:

readableInstant - a readable instant to check against

Returns:

negative value if this is less, 0 if equal, or positive value if greater

Throws:

NullPointerException - if the object is null

ClassCastException - if the object type is not supported

isEqual

public boolean isEqual(ReadableInstant instant)

Is this instant equal to the instant passed in comparing solely by millisecond.

Parameters:

instant - an instant to check against, null means now

Returns:

true if the instant is equal to the instant passed in

isAfter

public boolean isAfter(ReadableInstant instant)

Is this instant after the instant passed in comparing solely by millisecond.

Parameters:

instant - an instant to check against, null means now

Returns:

true if the instant is after the instant passed in

isBefore

public boolean isBefore(ReadableInstant instant)

Is this instant before the instant passed in comparing solely by millisecond.

Parameters:

instant - an instant to check against, null means now

Returns:

true if the instant is before the instant passed in

equals

public boolean equals(Object readableInstant)

Compares this object with the specified object for equality based on the millisecond instant and the Chronology. All ReadableInstant instances are accepted.

To compare two instants for absolute time (ie. UTC milliseconds ignoring the chronology), use isEqual(ReadableInstant) or compareTo(Object).

Parameters:

readableInstant - a readable instant to check against

Returns:

true if millisecond and chronology are equal, false if not or the instant is null or of an incorrect type

hashCode

public int hashCode()

Gets a hash code for the instant that is compatible with the equals method.

The formula used must be as follows:

 ((int) (getMillis() ^ (getMillis() >>> 32))) +
 (getChronology().hashCode())
 

Returns:

a hash code as defined above

toString

public String toString()

Get the value as a String in a recognisable ISO8601 format.

The string output is in ISO8601 format to enable the String constructor to correctly parse it.

Returns:

the value as an ISO8601 string