org.joda.time.field
Class DecoratedDurationField

java.lang.Object
  org.joda.time.DurationField
      org.joda.time.field.BaseDurationField
          org.joda.time.field.DecoratedDurationField

All Implemented Interfaces:

Serializable, Comparable<DurationField>

Direct Known Subclasses:

ScaledDurationField

public class DecoratedDurationField
extends BaseDurationField

DecoratedDurationField extends BaseDurationField, implementing only the minimum required set of methods. These implemented methods delegate to a wrapped field.

This design allows new DurationField types to be defined that piggyback on top of another, inheriting all the safe method implementations from BaseDurationField. Should any method require pure delegation to the wrapped field, simply override and use the provided getWrappedField method.

DecoratedDurationField is thread-safe and immutable, and its subclasses must be as well.

Since:

1.0

Author:

Brian S O'Neill

See Also:

DelegatedDurationField, Serialized Form

Constructor Summary

DecoratedDurationField(DurationField field, DurationFieldType type)
Constructor.

Method Summary

long	add(long instant, int value) Adds a duration value (which may be negative) to the instant.
long	add(long instant, long value) Adds a duration value (which may be negative) to the instant.
long	getDifferenceAsLong(long minuendInstant, long subtrahendInstant) Computes the difference between two instants, as measured in the units of this field.
long	getMillis(int value, long instant) Get the millisecond duration of this field from its value relative to an instant.
long	getMillis(long value, long instant) Get the millisecond duration of this field from its value relative to an instant.
long	getUnitMillis() Returns the amount of milliseconds per unit value of this field.
long	getValueAsLong(long duration, long instant) Get the value of this field from the milliseconds relative to an instant.
DurationField	getWrappedField() Gets the wrapped duration field.
boolean	isPrecise() Is this field precise.

Methods inherited from class org.joda.time.field.BaseDurationField

compareTo, getDifference, getMillis, getMillis, getName, getType, getValue, getValue, getValueAsLong, isSupported, toString

Methods inherited from class org.joda.time.DurationField

subtract, subtract

Methods inherited from class java.lang.Object

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

Constructor Detail

DecoratedDurationField

public DecoratedDurationField(DurationField field,
                              DurationFieldType type)

Constructor.

Parameters:

field - the base field

type - the type to actually use

Method Detail

getWrappedField

public final DurationField getWrappedField()

Gets the wrapped duration field.

Returns:

the wrapped DurationField

isPrecise

public boolean isPrecise()

Description copied from class: DurationField

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.

Specified by:

isPrecise in class DurationField

Returns:

true if precise

See Also:

DurationField.getUnitMillis()

getValueAsLong

public long getValueAsLong(long duration,
                           long instant)

Description copied from class: DurationField

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".

Specified by:

getValueAsLong in class DurationField

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 long getMillis(int value,
                      long instant)

Description copied from class: DurationField

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".

Specified by:

getMillis in class DurationField

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 long getMillis(long value,
                      long instant)

Description copied from class: DurationField

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".

Specified by:

getMillis in class DurationField

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 long add(long instant,
                int value)

Description copied from class: DurationField

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

Specified by:

add in class DurationField

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 long add(long instant,
                long value)

Description copied from class: DurationField

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

Specified by:

add in class DurationField

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

getDifferenceAsLong

public long getDifferenceAsLong(long minuendInstant,
                                long subtrahendInstant)

Description copied from class: DurationField

Computes the difference between two instants, as measured in the units of this field. Any fractional units are dropped from the result. Calling getDifference reverses the effect of calling add. In the following code:

 long instant = ...
 long v = ...
 long age = getDifferenceAsLong(add(instant, v), instant);
 

The value 'age' is the same as the value 'v'.

Specified by:

getDifferenceAsLong in class DurationField

Parameters:

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

subtrahendInstant - the milliseconds from 1970-01-01T00:00:00Z to subtract off the minuend

Returns:

the difference in the units of this field

getUnitMillis

public long getUnitMillis()

Description copied from class: DurationField

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.

Specified by:

getUnitMillis in class DurationField

Returns:

the unit size of this field, in milliseconds

See Also:

DurationField.isPrecise()