public final class MonthDay extends Object implements TemporalAccessor, TemporalAdjuster, Comparable<MonthDay>, Serializable
--12-03
.
MonthDay
is an immutable date-time object that represents the combination
of a month and day-of-month. Any field that can be derived from a month and day,
such as quarter-of-year, can be obtained.
This class does not store or represent a year, time or time-zone.
For example, the value "December 3rd" can be stored in a MonthDay
.
Since a MonthDay
does not possess a year, the leap day of
February 29th is considered valid.
This class implements TemporalAccessor
rather than Temporal
.
This is because it is not possible to define whether February 29th is valid or not
without external information, preventing the implementation of plus/minus.
Related to this, MonthDay
only provides access to query and set the fields
MONTH_OF_YEAR
and DAY_OF_MONTH
.
The ISO-8601 calendar system is the modern civil calendar system used today in most of the world. It is equivalent to the proleptic Gregorian calendar system, in which today's rules for leap years are applied for all time. For most applications written today, the ISO-8601 rules are entirely suitable. However, any application that makes use of historical dates, and requires them to be accurate will find the ISO-8601 approach unsuitable.
This is a value-based
class; use of identity-sensitive operations (including reference equality
(==
), identity hash code, or synchronization) on instances of
MonthDay
may have unpredictable results and should be avoided.
The equals
method should be used for comparisons.
Modifier and Type | Method and Description |
---|---|
Temporal |
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this month-day.
|
LocalDate |
atYear(int year)
Combines this month-day with a year to create a
LocalDate . |
int |
compareTo(MonthDay other)
Compares this month-day to another month-day.
|
boolean |
equals(Object obj)
Checks if this month-day is equal to another month-day.
|
String |
format(DateTimeFormatter formatter)
Formats this month-day using the specified formatter.
|
static MonthDay |
from(TemporalAccessor temporal)
Obtains an instance of
MonthDay from a temporal object. |
int |
get(TemporalField field)
Gets the value of the specified field from this month-day as an
int . |
int |
getDayOfMonth()
Gets the day-of-month field.
|
long |
getLong(TemporalField field)
Gets the value of the specified field from this month-day as a
long . |
Month |
getMonth()
Gets the month-of-year field using the
Month enum. |
int |
getMonthValue()
Gets the month-of-year field from 1 to 12.
|
int |
hashCode()
A hash code for this month-day.
|
boolean |
isAfter(MonthDay other)
Checks if this month-day is after the specified month-day.
|
boolean |
isBefore(MonthDay other)
Checks if this month-day is before the specified month-day.
|
boolean |
isSupported(TemporalField field)
Checks if the specified field is supported.
|
boolean |
isValidYear(int year)
Checks if the year is valid for this month-day.
|
static MonthDay |
now()
Obtains the current month-day from the system clock in the default time-zone.
|
static MonthDay |
now(Clock clock)
Obtains the current month-day from the specified clock.
|
static MonthDay |
now(ZoneId zone)
Obtains the current month-day from the system clock in the specified time-zone.
|
static MonthDay |
of(int month,
int dayOfMonth)
Obtains an instance of
MonthDay . |
static MonthDay |
of(Month month,
int dayOfMonth)
Obtains an instance of
MonthDay . |
static MonthDay |
parse(CharSequence text)
Obtains an instance of
MonthDay from a text string such as --12-03 . |
static MonthDay |
parse(CharSequence text,
DateTimeFormatter formatter)
Obtains an instance of
MonthDay from a text string using a specific formatter. |
<R> R |
query(TemporalQuery<R> query)
Queries this month-day using the specified query.
|
ValueRange |
range(TemporalField field)
Gets the range of valid values for the specified field.
|
String |
toString()
Outputs this month-day as a
String , such as --12-03 . |
MonthDay |
with(Month month)
Returns a copy of this
MonthDay with the month-of-year altered. |
MonthDay |
withDayOfMonth(int dayOfMonth)
Returns a copy of this
MonthDay with the day-of-month altered. |
MonthDay |
withMonth(int month)
Returns a copy of this
MonthDay with the month-of-year altered. |
public static MonthDay now()
This will query the system clock
in the default
time-zone to obtain the current month-day.
Using this method will prevent the ability to use an alternate clock for testing because the clock is hard-coded.
public static MonthDay now(ZoneId zone)
This will query the system clock
to obtain the current month-day.
Specifying the time-zone avoids dependence on the default time-zone.
Using this method will prevent the ability to use an alternate clock for testing because the clock is hard-coded.
zone
- the zone ID to use, not nullpublic static MonthDay now(Clock clock)
This will query the specified clock to obtain the current month-day.
Using this method allows the use of an alternate clock for testing.
The alternate clock may be introduced using dependency injection
.
clock
- the clock to use, not nullpublic static MonthDay of(Month month, int dayOfMonth)
MonthDay
.
The day-of-month must be valid for the month within a leap year. Hence, for February, day 29 is valid.
For example, passing in April and day 31 will throw an exception, as there can never be April 31st in any year. By contrast, passing in February 29th is permitted, as that month-day can sometimes be valid.
month
- the month-of-year to represent, not nulldayOfMonth
- the day-of-month to represent, from 1 to 31DateTimeException
- if the value of any field is out of range,
or if the day-of-month is invalid for the monthpublic static MonthDay of(int month, int dayOfMonth)
MonthDay
.
The day-of-month must be valid for the month within a leap year. Hence, for month 2 (February), day 29 is valid.
For example, passing in month 4 (April) and day 31 will throw an exception, as there can never be April 31st in any year. By contrast, passing in February 29th is permitted, as that month-day can sometimes be valid.
month
- the month-of-year to represent, from 1 (January) to 12 (December)dayOfMonth
- the day-of-month to represent, from 1 to 31DateTimeException
- if the value of any field is out of range,
or if the day-of-month is invalid for the monthpublic static MonthDay from(TemporalAccessor temporal)
MonthDay
from a temporal object.
This obtains a month-day based on the specified temporal.
A TemporalAccessor
represents an arbitrary set of date and time information,
which this factory converts to an instance of MonthDay
.
The conversion extracts the MONTH_OF_YEAR
and
DAY_OF_MONTH
fields.
The extraction is only permitted if the temporal object has an ISO
chronology, or can be converted to a LocalDate
.
This method matches the signature of the functional interface TemporalQuery
allowing it to be used as a query via method reference, MonthDay::from
.
temporal
- the temporal object to convert, not nullDateTimeException
- if unable to convert to a MonthDay
public static MonthDay parse(CharSequence text)
MonthDay
from a text string such as --12-03
.
The string must represent a valid month-day.
The format is --MM-dd
.
text
- the text to parse such as "--12-03", not nullDateTimeParseException
- if the text cannot be parsedpublic static MonthDay parse(CharSequence text, DateTimeFormatter formatter)
MonthDay
from a text string using a specific formatter.
The text is parsed using the formatter, returning a month-day.
text
- the text to parse, not nullformatter
- the formatter to use, not nullDateTimeParseException
- if the text cannot be parsedpublic boolean isSupported(TemporalField field)
This checks if this month-day can be queried for the specified field.
If false, then calling the range
and
get
methods will throw an exception.
If the field is a ChronoField
then the query is implemented here.
The supported fields are:
MONTH_OF_YEAR
YEAR
ChronoField
instances will return false.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.isSupportedBy(TemporalAccessor)
passing this
as the argument.
Whether the field is supported is determined by the field.
isSupported
in interface TemporalAccessor
field
- the field to check, null returns falsepublic ValueRange range(TemporalField field)
The range object expresses the minimum and maximum valid values for a field. This month-day is used to enhance the accuracy of the returned range. If it is not possible to return the range, because the field is not supported or for some other reason, an exception is thrown.
If the field is a ChronoField
then the query is implemented here.
The supported fields
will return
appropriate range instances.
All other ChronoField
instances will throw an UnsupportedTemporalTypeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.rangeRefinedBy(TemporalAccessor)
passing this
as the argument.
Whether the range can be obtained is determined by the field.
range
in interface TemporalAccessor
field
- the field to query the range for, not nullDateTimeException
- if the range for the field cannot be obtainedUnsupportedTemporalTypeException
- if the field is not supportedpublic int get(TemporalField field)
int
.
This queries this month-day for the value of the specified field. The returned value will always be within the valid range of values for the field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.
If the field is a ChronoField
then the query is implemented here.
The supported fields
will return valid
values based on this month-day.
All other ChronoField
instances will throw an UnsupportedTemporalTypeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.getFrom(TemporalAccessor)
passing this
as the argument. Whether the value can be obtained,
and what the value represents, is determined by the field.
get
in interface TemporalAccessor
field
- the field to get, not nullDateTimeException
- if a value for the field cannot be obtained or
the value is outside the range of valid values for the fieldUnsupportedTemporalTypeException
- if the field is not supported or
the range of values exceeds an int
ArithmeticException
- if numeric overflow occurspublic long getLong(TemporalField field)
long
.
This queries this month-day for the value of the specified field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.
If the field is a ChronoField
then the query is implemented here.
The supported fields
will return valid
values based on this month-day.
All other ChronoField
instances will throw an UnsupportedTemporalTypeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.getFrom(TemporalAccessor)
passing this
as the argument. Whether the value can be obtained,
and what the value represents, is determined by the field.
getLong
in interface TemporalAccessor
field
- the field to get, not nullDateTimeException
- if a value for the field cannot be obtainedUnsupportedTemporalTypeException
- if the field is not supportedArithmeticException
- if numeric overflow occurspublic int getMonthValue()
This method returns the month as an int
from 1 to 12.
Application code is frequently clearer if the enum Month
is used by calling getMonth()
.
getMonth()
public Month getMonth()
Month
enum.
This method returns the enum Month
for the month.
This avoids confusion as to what int
values mean.
If you need access to the primitive int
value then the enum
provides the int value
.
getMonthValue()
public int getDayOfMonth()
This method returns the primitive int
value for the day-of-month.
public boolean isValidYear(int year)
This method checks whether this month and day and the input year form a valid date. This can only return false for February 29th.
year
- the year to validateYear.isValidMonthDay(MonthDay)
public MonthDay withMonth(int month)
MonthDay
with the month-of-year altered.
This returns a month-day with the specified month. If the day-of-month is invalid for the specified month, the day will be adjusted to the last valid day-of-month.
This instance is immutable and unaffected by this method call.
month
- the month-of-year to set in the returned month-day, from 1 (January) to 12 (December)MonthDay
based on this month-day with the requested month, not nullDateTimeException
- if the month-of-year value is invalidpublic MonthDay with(Month month)
MonthDay
with the month-of-year altered.
This returns a month-day with the specified month. If the day-of-month is invalid for the specified month, the day will be adjusted to the last valid day-of-month.
This instance is immutable and unaffected by this method call.
month
- the month-of-year to set in the returned month-day, not nullMonthDay
based on this month-day with the requested month, not nullpublic MonthDay withDayOfMonth(int dayOfMonth)
MonthDay
with the day-of-month altered.
This returns a month-day with the specified day-of-month. If the day-of-month is invalid for the month, an exception is thrown.
This instance is immutable and unaffected by this method call.
dayOfMonth
- the day-of-month to set in the return month-day, from 1 to 31MonthDay
based on this month-day with the requested day, not nullDateTimeException
- if the day-of-month value is invalid,
or if the day-of-month is invalid for the monthpublic <R> R query(TemporalQuery<R> query)
This queries this month-day using the specified query strategy object.
The TemporalQuery
object defines the logic to be used to
obtain the result. Read the documentation of the query to understand
what the result of this method will be.
The result of this method is obtained by invoking the
TemporalQuery.queryFrom(TemporalAccessor)
method on the
specified query passing this
as the argument.
query
in interface TemporalAccessor
R
- the type of the resultquery
- the query to invoke, not nullDateTimeException
- if unable to query (defined by the query)ArithmeticException
- if numeric overflow occurs (defined by the query)public Temporal adjustInto(Temporal temporal)
This returns a temporal object of the same observable type as the input with the month and day-of-month changed to be the same as this.
The adjustment is equivalent to using Temporal.with(TemporalField, long)
twice, passing ChronoField.MONTH_OF_YEAR
and
ChronoField.DAY_OF_MONTH
as the fields.
If the specified temporal object does not use the ISO calendar system then
a DateTimeException
is thrown.
In most cases, it is clearer to reverse the calling pattern by using
Temporal.with(TemporalAdjuster)
:
// these two lines are equivalent, but the second approach is recommended temporal = thisMonthDay.adjustInto(temporal); temporal = temporal.with(thisMonthDay);
This instance is immutable and unaffected by this method call.
adjustInto
in interface TemporalAdjuster
temporal
- the target object to be adjusted, not nullDateTimeException
- if unable to make the adjustmentArithmeticException
- if numeric overflow occurspublic String format(DateTimeFormatter formatter)
This month-day will be passed to the formatter to produce a string.
formatter
- the formatter to use, not nullDateTimeException
- if an error occurs during printingpublic LocalDate atYear(int year)
LocalDate
.
This returns a LocalDate
formed from this month-day and the specified year.
A month-day of February 29th will be adjusted to February 28th in the resulting date if the year is not a leap year.
This instance is immutable and unaffected by this method call.
year
- the year to use, from MIN_YEAR to MAX_YEARDateTimeException
- if the year is outside the valid range of yearspublic int compareTo(MonthDay other)
The comparison is based first on value of the month, then on the value of the day.
It is "consistent with equals", as defined by Comparable
.
compareTo
in interface Comparable<MonthDay>
other
- the other month-day to compare to, not nullpublic boolean isAfter(MonthDay other)
other
- the other month-day to compare to, not nullpublic boolean isBefore(MonthDay other)
other
- the other month-day to compare to, not nullpublic boolean equals(Object obj)
The comparison is based on the time-line position of the month-day within a year.
equals
in class Object
obj
- the object to check, null returns falseObject.hashCode()
,
HashMap
public int hashCode()
hashCode
in class Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
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