org.goda.time

Class DurationField

java.lang.Object

org.goda.time.Field

org.goda.time.DurationField

All Implemented Interfaces:

Comparable

Direct Known Subclasses:

BaseDurationField, DelegatedDurationField, MillisDurationField, UnsupportedDurationField

public abstract class DurationField
extends Field
implements Comparable

Defines the calculation engine for duration fields. The interface defines a set of methods that manipulate a millisecond duration with regards to a single field, such as months or seconds.

This design is extensible so, if you wish, you can extract a different field from the millisecond duration. A number of standard implementations are provided to assist.

Since:

1.0

Author:

Stephen Colebourne, Brian S O'Neill

Constructor Summary

Constructors

Constructor and Description
DurationField()

Method Summary

Methods

Modifier and Type	Method and Description
abstract long	add(long instant, int value) Adds a duration value (which may be negative) to the instant.
abstract long	add(long instant, long value) Adds a duration value (which may be negative) to the instant.
abstract int	compareTo(Object durationField) Compares this duration field with another duration field for ascending unit millisecond order.
abstract long	getMillis(int value) Get the millisecond duration of this field from its value, which is approximate if this field is imprecise.
abstract long	getMillis(int value, long instant) Get the millisecond duration of this field from its value relative to an instant.
abstract long	getMillis(long value) Get the millisecond duration of this field from its value, which is approximate if this field is imprecise.
abstract long	getMillis(long value, long instant) Get the millisecond duration of this field from its value relative to an instant.
abstract DurationFieldType	getType() Get the type of the field.
abstract long	getUnitMillis() Returns the amount of milliseconds per unit value of this field.
abstract int	getValue(long duration) Get the value of this field from the milliseconds, which is approximate if this field is imprecise.
abstract int	getValue(long duration, long instant) Get the value of this field from the milliseconds relative to an instant.
abstract long	getValueAsLong(long duration) Get the value of this field from the milliseconds, which is approximate if this field is imprecise.
abstract long	getValueAsLong(long duration, long instant) Get the value of this field from the milliseconds relative to an instant.
abstract boolean	isPrecise() Is this field precise.
long	subtract(long instant, int value) Subtracts a duration value (which may be negative) from the instant.
long	subtract(long instant, long value) Subtracts a duration value (which may be negative) from the instant.
abstract String	toString() Get a suitable debug string.

Methods inherited from class org.goda.time.Field

getDifference, getDifferenceAsLong, getName, isSupported

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DurationField

public DurationField()

Method Detail

getType

public abstract DurationFieldType getType()

Get the type of the field.

Returns:

field type

isPrecise

public abstract boolean isPrecise()

Is this field precise. A precise field can calculate its value from milliseconds without needing a reference date. Put another way, a precise field's unit size is not variable.

Returns:

true if precise

See Also:

getUnitMillis()

getUnitMillis

public abstract long getUnitMillis()

Returns the amount of milliseconds per unit value of this field. For example, if this field represents "seconds", then this returns the milliseconds in one second.

For imprecise fields, the unit size is variable, and so this method returns a suitable average value.

Returns:

the unit size of this field, in milliseconds

See Also:

isPrecise()

getValue

public abstract int getValue(long duration)

Get the value of this field from the milliseconds, which is approximate if this field is imprecise.

Parameters:

duration - the milliseconds to query, which may be negative

Returns:

the value of the field, in the units of the field, which may be negative

Throws:

ArithmeticException - if the value is too large for an int

getValueAsLong

public abstract long getValueAsLong(long duration)

Get the value of this field from the milliseconds, which is approximate if this field is imprecise.

Parameters:

duration - the milliseconds to query, which may be negative

Returns:

the value of the field, in the units of the field, which may be negative

getValue

public abstract int getValue(long duration,
           long instant)

Get the value of this field from the milliseconds relative to an instant. For precise fields this method produces the same result as for the single argument get method.

If the millisecond duration is positive, then the instant is treated as a "start instant". If negative, the instant is treated as an "end instant".

Parameters:

duration - the milliseconds to query, which may be negative

instant - the start instant to calculate relative to

Returns:

the value of the field, in the units of the field, which may be negative

Throws:

ArithmeticException - if the value is too large for an int

getValueAsLong

public abstract long getValueAsLong(long duration,
                  long instant)

Get the value of this field from the milliseconds relative to an instant. For precise fields this method produces the same result as for the single argument get method.

If the millisecond duration is positive, then the instant is treated as a "start instant". If negative, the instant is treated as an "end instant".

Parameters:

duration - the milliseconds to query, which may be negative

instant - the start instant to calculate relative to

Returns:

the value of the field, in the units of the field, which may be negative

getMillis

public abstract long getMillis(int value)

Get the millisecond duration of this field from its value, which is approximate if this field is imprecise.

Parameters:

value - the value of the field, which may be negative

Returns:

the milliseconds that the field represents, which may be negative

getMillis

public abstract long getMillis(long value)

Get the millisecond duration of this field from its value, which is approximate if this field is imprecise.

Parameters:

value - the value of the field, which may be negative

Returns:

the milliseconds that the field represents, which may be negative

getMillis

public abstract long getMillis(int value,
             long instant)

Get the millisecond duration of this field from its value relative to an instant. For precise fields this method produces the same result as for the single argument getMillis method.

If the value is positive, then the instant is treated as a "start instant". If negative, the instant is treated as an "end instant".

Parameters:

value - the value of the field, which may be negative

instant - the instant to calculate relative to

Returns:

the millisecond duration that the field represents, which may be negative

getMillis

public abstract long getMillis(long value,
             long instant)

Get the millisecond duration of this field from its value relative to an instant. For precise fields this method produces the same result as for the single argument getMillis method.

If the value is positive, then the instant is treated as a "start instant". If negative, the instant is treated as an "end instant".

Parameters:

value - the value of the field, which may be negative

instant - the instant to calculate relative to

Returns:

the millisecond duration that the field represents, which may be negative

add

public abstract long add(long instant,
       int value)

Adds a duration value (which may be negative) to the instant.

Specified by:

add in class Field

Parameters:

instant - the milliseconds from 1970-01-01T00:00:00Z to add to

value - the value to add, in the units of the field

Returns:

the updated milliseconds

add

public abstract long add(long instant,
       long value)

Adds a duration value (which may be negative) to the instant.

Specified by:

add in class Field

Parameters:

instant - the milliseconds from 1970-01-01T00:00:00Z to add to

value - the value to add, in the units of the field

Returns:

the updated milliseconds

subtract

public long subtract(long instant,
            int value)

Subtracts a duration value (which may be negative) from the instant.

Parameters:

instant - the milliseconds from 1970-01-01T00:00:00Z to subtract from

value - the value to subtract, in the units of the field

Returns:

the updated milliseconds

Since:

1.1

subtract

public long subtract(long instant,
            long value)

Subtracts a duration value (which may be negative) from the instant.

Parameters:

instant - the milliseconds from 1970-01-01T00:00:00Z to subtract from

value - the value to subtract, in the units of the field

Returns:

the updated milliseconds

Since:

1.1

compareTo

public abstract int compareTo(Object durationField)

Compares this duration field with another duration field for ascending unit millisecond order. This ordering is inconsistent with equals, as it ignores name and precision.

Specified by:

compareTo in interface Comparable

Parameters:

durationField - a duration field 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

toString

public abstract String toString()

Get a suitable debug string.

Specified by:

toString in class Field

Returns:

debug string