Class DurationField
 java.lang.Object

 org.joda.time.DurationField

 All Implemented Interfaces:
java.lang.Comparable<DurationField>
 Direct Known Subclasses:
BaseDurationField
,DelegatedDurationField
,MillisDurationField
,UnsupportedDurationField
public abstract class DurationField extends java.lang.Object implements java.lang.Comparable<DurationField>
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


Constructor Summary
Constructors Constructor Description DurationField()

Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method 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
getDifference(long minuendInstant, long subtrahendInstant)
Computes the difference between two instants, as measured in the units of this field.abstract long
getDifferenceAsLong(long minuendInstant, long subtrahendInstant)
Computes the difference between two instants, as measured in the units of this field.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 java.lang.String
getName()
Get the name of the field.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.abstract boolean
isSupported()
Returns true if this field is supported.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 java.lang.String
toString()
Get a suitable debug string.



Method Detail

getType
public abstract DurationFieldType getType()
Get the type of the field. Returns:
 field type

getName
public abstract java.lang.String getName()
Get the name of the field.By convention, names are plural.
 Returns:
 field name

isSupported
public abstract boolean isSupported()
Returns true if this field is supported. Returns:
 true if this field is supported

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:
java.lang.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 negativeinstant
 the start instant to calculate relative to Returns:
 the value of the field, in the units of the field, which may be negative
 Throws:
java.lang.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 negativeinstant
 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 negativeinstant
 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 negativeinstant
 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. Parameters:
instant
 the milliseconds from 19700101T00:00:00Z to add tovalue
 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. Parameters:
instant
 the milliseconds from 19700101T00:00:00Z to add tovalue
 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 19700101T00:00:00Z to subtract fromvalue
 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 19700101T00:00:00Z to subtract fromvalue
 the value to subtract, in the units of the field Returns:
 the updated milliseconds
 Since:
 1.1

getDifference
public abstract int getDifference(long minuendInstant, long subtrahendInstant)
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 = ... int v = ... int age = getDifference(add(instant, v), instant);
The value 'age' is the same as the value 'v'. Parameters:
minuendInstant
 the milliseconds from 19700101T00:00:00Z to subtract fromsubtrahendInstant
 the milliseconds from 19700101T00:00:00Z to subtract off the minuend Returns:
 the difference in the units of this field

getDifferenceAsLong
public abstract long getDifferenceAsLong(long minuendInstant, long subtrahendInstant)
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'. Parameters:
minuendInstant
 the milliseconds from 19700101T00:00:00Z to subtract fromsubtrahendInstant
 the milliseconds from 19700101T00:00:00Z to subtract off the minuend Returns:
 the difference in the units of this field

toString
public abstract java.lang.String toString()
Get a suitable debug string. Overrides:
toString
in classjava.lang.Object
 Returns:
 debug string

