Immutable representation of a time span as defined in the W3C XML Schema 1.0 specification.
A Duration object represents a period of Gregorian time, which consists of six fields (years, months, days, hours, minutes, and seconds) plus a sign (+/) field.
The first five fields have nonnegative (>=0) integers or null (which represents that the field is not set), and the seconds field has a nonnegative decimal or null. A negative sign indicates a negative duration.
This class provides a number of methods that make it easy to use for the duration datatype of XML Schema 1.0 with the errata.
Order relationship
Duration objects only have partial order, where two values A and B maybe either:
 A<B (A is shorter than B)
 A>B (A is longer than B)
 A==B (A and B are of the same duration)
 A<>B (Comparison between A and B is indeterminate)
For example, 30 days cannot be meaningfully compared to one month.
The compare(Duration duration)
method implements this
relationship.
See the isLongerThan(Duration)
method for details about
the order relationship among Duration
objects.
Operations over Duration
This class provides a set of basic arithmetic operations, such as addition, subtraction and multiplication. Because durations don't have total order, an operation could fail for some combinations of operations. For example, you cannot subtract 15 days from 1 month. See the javadoc of those methods for detailed conditions where this could happen.
Also, division of a duration by a number is not provided because
the Duration
class can only deal with finite precision
decimal numbers. For example, one cannot represent 1 sec divided by 3.
However, you could substitute a division by 3 with multiplying by numbers such as 0.3 or 0.333.
Range of allowed values
Because some operations of Duration
rely on Calendar
even though Duration
can hold very large or very small values,
some of the methods may not work correctly on such Duration
s.
The impacted methods document their dependency on Calendar
.
 Since:
 1.5
 See Also:

Constructor Summary

Method Summary
Modifier and TypeMethodDescriptionabstract Duration
Computes a new duration whose value isthis+rhs
.abstract void
Adds this duration to aCalendar
object.void
Adds this duration to aDate
object.abstract int
Partial order relation comparison with thisDuration
instance.boolean
Checks if this duration object has the same duration as anotherDuration
object.int
getDays()
Obtains the value of the DAYS field as an integer value, or 0 if not present.abstract Number
getField
(DatatypeConstants.Field field) Gets the value of a field.int
getHours()
Obtains the value of the HOURS field as an integer value, or 0 if not present.int
Obtains the value of the MINUTES field as an integer value, or 0 if not present.int
Obtains the value of the MONTHS field as an integer value, or 0 if not present.int
Obtains the value of the SECONDS field as an integer value, or 0 if not present.abstract int
getSign()
Returns the sign of this duration in 1,0, or 1.long
getTimeInMillis
(Calendar startInstant) Returns the length of the duration in milliseconds.long
getTimeInMillis
(Date startInstant) Returns the length of the duration in milliseconds.Return the name of the XML Schema date/time type that this instance maps to.int
getYears()
Get the years value of thisDuration
as anint
or0
if not present.abstract int
hashCode()
Returns a hash code consistent with the definition of the equals method.boolean
isLongerThan
(Duration duration) Checks if this duration object is strictly longer than anotherDuration
object.abstract boolean
isSet
(DatatypeConstants.Field field) Checks if a field is set.boolean
isShorterThan
(Duration duration) Checks if this duration object is strictly shorter than anotherDuration
object.multiply
(int factor) Computes a new duration whose value isfactor
times longer than the value of this duration.abstract Duration
multiply
(BigDecimal factor) Computes a new duration whose value isfactor
times longer than the value of this duration.abstract Duration
negate()
Returns a newDuration
object whose value isthis
.abstract Duration
normalizeWith
(Calendar startTimeInstant) Converts the years and months fields into the days field by using a specific time instant as the reference point.Computes a new duration whose value isthisrhs
.toString()
Returns aString
representation of thisDuration Object
.

Constructor Details

Duration
public Duration()Default noarg constructor.Note: Always use the
DatatypeFactory
to construct an instance ofDuration
. The constructor on this class cannot be guaranteed to produce an object with a consistent state and may be removed in the future.


Method Details

getXMLSchemaType
Return the name of the XML Schema date/time type that this instance maps to. Type is computed based on fields that are set, i.e.isSet(DatatypeConstants.Field field)
==true
.Required fields for XML Schema 1.0 Date/Time Datatypes.
(timezone is optional for all date/time datatypes)Datatype year month day hour minute second DatatypeConstants.DURATION
X X X X X X DatatypeConstants.DURATION_DAYTIME
X X X X DatatypeConstants.DURATION_YEARMONTH
X X  Returns:
 one of the following constants:
DatatypeConstants.DURATION
,DatatypeConstants.DURATION_DAYTIME
orDatatypeConstants.DURATION_YEARMONTH
.  Throws:
IllegalStateException
 If the combination of set fields does not match one of the XML Schema date/time datatypes.

getSign
public abstract int getSign()Returns the sign of this duration in 1,0, or 1. Returns:
 1 if this duration is negative, 0 if the duration is zero, and 1 if the duration is positive.

getYears
public int getYears()Get the years value of thisDuration
as anint
or0
if not present.getYears()
is a convenience method forgetField(DatatypeConstants.YEARS)
.As the return value is an
int
, an incorrect value will be returned forDuration
s with years that go beyond the range of anint
. UsegetField(DatatypeConstants.YEARS)
to avoid possible loss of precision. Returns:
 If the years field is present, return its value as an
int
, else return0
.

getMonths
public int getMonths()Obtains the value of the MONTHS field as an integer value, or 0 if not present. This method works just likegetYears()
except that this method works on the MONTHS field. Returns:
 Months of this
Duration
.

getDays
public int getDays()Obtains the value of the DAYS field as an integer value, or 0 if not present. This method works just likegetYears()
except that this method works on the DAYS field. Returns:
 Days of this
Duration
.

getHours
public int getHours()Obtains the value of the HOURS field as an integer value, or 0 if not present. This method works just likegetYears()
except that this method works on the HOURS field. Returns:
 Hours of this
Duration
.

getMinutes
public int getMinutes()Obtains the value of the MINUTES field as an integer value, or 0 if not present. This method works just likegetYears()
except that this method works on the MINUTES field. Returns:
 Minutes of this
Duration
.

getSeconds
public int getSeconds()Obtains the value of the SECONDS field as an integer value, or 0 if not present. This method works just likegetYears()
except that this method works on the SECONDS field. Returns:
 seconds in the integer value. The fraction of seconds will be discarded (for example, if the actual value is 2.5, this method returns 2)

getTimeInMillis
Returns the length of the duration in milliseconds.If the seconds field carries more digits than millisecond order, those will be simply discarded (or in other words, rounded to zero.) For example, for any Calendar value
x
,new Duration("PT10.00099S").getTimeInMills(x) == 10000
new Duration("PT10.00099S").getTimeInMills(x) == 10000
Note that this method uses the
addTo(Calendar)
method, which may work incorrectly withDuration
objects with very large values in its fields. See theaddTo(Calendar)
method for details. Parameters:
startInstant
 The length of a month/year varies. ThestartInstant
is used to disambiguate this variance. Specifically, this method returns the difference betweenstartInstant
andstartInstant+duration
 Returns:
 milliseconds between
startInstant
andstartInstant
plus thisDuration
 Throws:
NullPointerException
 ifstartInstant
parameter is null.

getTimeInMillis
Returns the length of the duration in milliseconds.If the seconds field carries more digits than millisecond order, those will be simply discarded (or in other words, rounded to zero.) For example, for any
Date
valuex
,new Duration("PT10.00099S").getTimeInMills(x) == 10000
new Duration("PT10.00099S").getTimeInMills(x) == 10000
Note that this method uses the
addTo(Date)
method, which may work incorrectly withDuration
objects with very large values in its fields. See theaddTo(Date)
method for details. Parameters:
startInstant
 The length of a month/year varies. ThestartInstant
is used to disambiguate this variance. Specifically, this method returns the difference betweenstartInstant
andstartInstant+duration
. Returns:
 milliseconds between
startInstant
andstartInstant
plus thisDuration
 Throws:
NullPointerException
 If the startInstant parameter is null. See Also:

getField
Gets the value of a field. Fields of a duration object may contain arbitrary large value. Therefore this method is designed to return aNumber
object. In case of YEARS, MONTHS, DAYS, HOURS, and MINUTES, the returned number will be a nonnegative integer. In case of seconds, the returned number may be a nonnegative decimal value. Parameters:
field
 one of the six Field constants (YEARS,MONTHS,DAYS,HOURS, MINUTES, or SECONDS.) Returns:
 If the specified field is present, this method returns
a nonnull nonnegative
Number
object that represents its value. If it is not present, return null. For YEARS, MONTHS, DAYS, HOURS, and MINUTES, this method returns aBigInteger
object. For SECONDS, this method returns aBigDecimal
.  Throws:
NullPointerException
 If thefield
isnull
.

isSet
Checks if a field is set. A field of a duration object may or may not be present. This method can be used to test if a field is present. Parameters:
field
 one of the six Field constants (YEARS,MONTHS,DAYS,HOURS, MINUTES, or SECONDS.) Returns:
 true if the field is present. false if not.
 Throws:
NullPointerException
 If the field parameter is null.

add
Computes a new duration whose value isthis+rhs
.For example,
"1 day" + "3 days" = "2 days" "1 year" + "1 day" = "1 year and 1 day" "(1 hour,50 minutes)" + "20 minutes" = "(1 hours,70 minutes)" "15 hours" + "3 days" = "(2 days,9 hours)" "1 year" + "1 day" = IllegalStateException
Since there's no way to meaningfully subtract 1 day from 1 month, there are cases where the operation fails in
IllegalStateException
.Formally, the computation is defined as follows.
Firstly, we can assume that two
Duration
s to be added are both positive without losing generality (i.e.,(X)+Y=YX
,X+(Y)=XY
,(X)+(Y)=(X+Y)
)Addition of two positive
Duration
s are simply defined as field by field addition where missing fields are treated as 0.A field of the resulting
Duration
will be unset if and only if respective fields of two inputDuration
s are unset.Note that
lhs.add(rhs)
will be always successful iflhs.signum()*rhs.signum()!=1
or both of them are normalized. Parameters:
rhs
Duration
to add to thisDuration
 Returns:
 nonnull valid Duration object.
 Throws:
NullPointerException
 If the rhs parameter is null.IllegalStateException
 If two durations cannot be meaningfully added. For example, adding negative one day to one month causes this exception. See Also:

addTo
Adds this duration to aCalendar
object.Calls
Calendar.add(int,int)
in the order of YEARS, MONTHS, DAYS, HOURS, MINUTES, SECONDS, and MILLISECONDS if those fields are present. Because theCalendar
class uses int to hold values, there are cases where this method won't work correctly (for example if values of fields exceed the range of int.)Also, since this duration class is a Gregorian duration, this method will not work correctly if the given
Calendar
object is based on some other calendar systems.Any fractional parts of this
Duration
object beyond milliseconds will be simply ignored. For example, if this duration is "P1.23456S", then 1 is added to SECONDS, 234 is added to MILLISECONDS, and the rest will be unused.Note that because
Calendar.add(int, int)
is usingint
,Duration
with values beyond the range ofint
in its fields will cause overflow/underflow to the givenCalendar
.XMLGregorianCalendar.add(Duration)
provides the same basic operation as this method while avoiding the overflow/underflow issues. Parameters:
calendar
 A calendar object whose value will be modified. Throws:
NullPointerException
 if the calendar parameter is null.

addTo
Adds this duration to aDate
object.The given date is first converted into a
GregorianCalendar
, then the duration is added exactly like theaddTo(Calendar)
method.The updated time instant is then converted back into a
Date
object and used to update the givenDate
object.This somewhat redundant computation is necessary to unambiguously determine the duration of months and years.
 Parameters:
date
 A date object whose value will be modified. Throws:
NullPointerException
 if the date parameter is null.

subtract
Computes a new duration whose value isthisrhs
.For example:
"1 day"  "3 days" = "4 days" "1 year"  "1 day" = IllegalStateException "(1 hour,50 minutes)"  "20 minutes" = "(1hours,30 minutes)" "15 hours"  "3 days" = "3 days and 15 hours" "1 year"  "1 day" = "1 year and 1 day"
Since there's no way to meaningfully subtract 1 day from 1 month, there are cases where the operation fails in
IllegalStateException
.Formally the computation is defined as follows. First, we can assume that two
Duration
s are both positive without losing generality. (i.e.,(X)Y=(X+Y)
,X(Y)=X+Y
,(X)(Y)=(XY)
)Then two durations are subtracted field by field. If the sign of any nonzero field
F
is different from the sign of the most significant field, 1 (ifF
is negative) or 1 (otherwise) will be borrowed from the next bigger unit ofF
.This process is repeated until all the nonzero fields have the same sign.
If a borrow occurs in the days field (in other words, if the computation needs to borrow 1 or 1 month to compensate days), then the computation fails by throwing an
IllegalStateException
. Parameters:
rhs
Duration
to subtract from thisDuration
. Returns:
 New
Duration
created from subtractingrhs
from thisDuration
.  Throws:
IllegalStateException
 If two durations cannot be meaningfully subtracted. For example, subtracting one day from one month causes this exception.NullPointerException
 If the rhs parameter is null. See Also:

multiply
Computes a new duration whose value isfactor
times longer than the value of this duration.This method is provided for the convenience. It is functionally equivalent to the following code:
multiply(new BigDecimal(String.valueOf(factor)))
 Parameters:
factor
 Factor times longer of newDuration
to create. Returns:
 New
Duration
that isfactor
times longer than thisDuration
.  See Also:

multiply
Computes a new duration whose value isfactor
times longer than the value of this duration.For example,
"P1M" (1 month) * "12" = "P12M" (12 months) "PT1M" (1 min) * "0.3" = "PT18S" (18 seconds) "P1M" (1 month) * "1.5" = IllegalStateException
Since the
Duration
class is immutable, this method doesn't change the value of this object. It simply computes a new Duration object and returns it.The operation will be performed field by field with the precision of
BigDecimal
. Since all the fields except seconds are restricted to hold integers, any fraction produced by the computation will be carried down toward the next lower unit. For example, if you multiply "P1D" (1 day) with "0.5", then it will be 0.5 day, which will be carried down to "PT12H" (12 hours). When fractions of month cannot be meaningfully carried down to days, or year to months, this will cause anIllegalStateException
to be thrown. For example if you multiple one month by 0.5.To avoid
IllegalStateException
, use thenormalizeWith(Calendar)
method to remove the years and months fields. Parameters:
factor
 to multiply by Returns:
 returns a nonnull valid
Duration
object  Throws:
IllegalStateException
 if operation produces fraction in the months field.NullPointerException
 if thefactor
parameter isnull
.

negate
Returns a newDuration
object whose value isthis
.Since the
Duration
class is immutable, this method doesn't change the value of this object. It simply computes a new Duration object and returns it. Returns:
 always return a nonnull valid
Duration
object.

normalizeWith
Converts the years and months fields into the days field by using a specific time instant as the reference point.For example, duration of one month normalizes to 31 days given the start time instance "July 8th 2003, 17:40:32".
Formally, the computation is done as follows:
 the given Calendar object is cloned
 the years, months and days fields will be added to the
Calendar
object by using theCalendar.add(int,int)
method  the difference between the two Calendars in computed in milliseconds and converted to days, if a remainder occurs due to Daylight Savings Time, it is discarded
 the computed days, along with the hours, minutes and seconds fields of this duration object is used to construct a new Duration object.
Note that since the Calendar class uses
int
to hold the value of year and month, this method may produce an unexpected result if this duration object holds a very large value in the years or months fields. Parameters:
startTimeInstant
Calendar
reference point. Returns:
Duration
of years and months of thisDuration
as days. Throws:
NullPointerException
 If the startTimeInstant parameter is null.

compare
Partial order relation comparison with thisDuration
instance.Comparison result must be in accordance with W3C XML Schema 1.0 Part 2, Section 3.2.7.6.2, Order relation on duration.
Return:
DatatypeConstants.LESSER
if thisDuration
is shorter thanduration
parameterDatatypeConstants.EQUAL
if thisDuration
is equal toduration
parameterDatatypeConstants.GREATER
if thisDuration
is longer thanduration
parameterDatatypeConstants.INDETERMINATE
if a conclusive partial order relation cannot be determined
 Parameters:
duration
 to compare Returns:
 the relationship between
this Duration
andduration
parameter asDatatypeConstants.LESSER
,DatatypeConstants.EQUAL
,DatatypeConstants.GREATER
orDatatypeConstants.INDETERMINATE
.  Throws:
UnsupportedOperationException
 If the underlying implementation cannot reasonably process the request, e.g. W3C XML Schema allows for arbitrarily large/small/precise values, the request may be beyond the implementations capability.NullPointerException
 ifduration
isnull
. See Also:

isLongerThan
Checks if this duration object is strictly longer than anotherDuration
object.Duration X is "longer" than Y if and only if X > Y as defined in the section 3.2.6.2 of the XML Schema 1.0 specification.
For example, "P1D" (one day) > "PT12H" (12 hours) and "P2Y" (two years) > "P23M" (23 months).
 Parameters:
duration
Duration
to test thisDuration
against. Returns:
 true if the duration represented by this object is longer than the given duration. false otherwise.
 Throws:
UnsupportedOperationException
 If the underlying implementation cannot reasonably process the request, e.g. W3C XML Schema allows for arbitrarily large/small/precise values, the request may be beyond the implementations capability.NullPointerException
 Ifduration
is null. See Also:

isShorterThan
Checks if this duration object is strictly shorter than anotherDuration
object. Parameters:
duration
Duration
to test thisDuration
against. Returns:
true
ifduration
parameter is shorter than thisDuration
, elsefalse
. Throws:
UnsupportedOperationException
 If the underlying implementation cannot reasonably process the request, e.g. W3C XML Schema allows for arbitrarily large/small/precise values, the request may be beyond the implementations capability.NullPointerException
 ifduration
is null. See Also:

equals
Checks if this duration object has the same duration as anotherDuration
object.For example, "P1D" (1 day) is equal to "PT24H" (24 hours).
Duration X is equal to Y if and only if time instant t+X and t+Y are the same for all the test time instants specified in the section 3.2.6.2 of the XML Schema 1.0 specification.
Note that there are cases where two
Duration
s are "incomparable" to each other, like one month and 30 days. For example,!new Duration("P1M").isShorterThan(new Duration("P30D")) !new Duration("P1M").isLongerThan(new Duration("P30D")) !new Duration("P1M").equals(new Duration("P30D"))
 Overrides:
equals
in classObject
 Parameters:
duration
 The object to compare thisDuration
against. Returns:
true
if this duration is the same length asduration
.false
ifduration
isnull
, is not aDuration
object, or its length is different from this duration. Throws:
UnsupportedOperationException
 If the underlying implementation cannot reasonably process the request, e.g. W3C XML Schema allows for arbitrarily large/small/precise values, the request may be beyond the implementations capability. See Also:

hashCode
public abstract int hashCode()Returns a hash code consistent with the definition of the equals method. 
toString
Returns aString
representation of thisDuration Object
.The result is formatted according to the XML Schema 1.0 spec and can be always parsed back later into the equivalent
Duration Object
byDatatypeFactory.newDuration(String lexicalRepresentation)
.Formally, the following holds for any
Duration
Object
x:new Duration(x.toString()).equals(x)
