- All Implemented Interfaces:
Serializable,Comparable<MonthDay>,TemporalAccessor,TemporalAdjuster
--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; programmers should treat instances that are
equal as interchangeable and should not
use instances for synchronization, or unpredictable behavior may
occur. For example, in a future release, synchronization may fail.
The equals method should be used for comparisons.
- Implementation Requirements:
- This class is immutable and thread-safe.
- Since:
- 1.8
- See Also:
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Method Summary
Modifier and TypeMethodDescriptionadjustInto(Temporal temporal) Adjusts the specified temporal object to have this month-day.atYear(int year) Combines this month-day with a year to create aLocalDate.intCompares this month-day to another month-day.booleanChecks if this month-day is equal to another month-day.format(DateTimeFormatter formatter) Formats this month-day using the specified formatter.static MonthDayfrom(TemporalAccessor temporal) Obtains an instance ofMonthDayfrom a temporal object.intget(TemporalField field) Gets the value of the specified field from this month-day as anint.intGets the day-of-month field.longgetLong(TemporalField field) Gets the value of the specified field from this month-day as along.getMonth()Gets the month-of-year field using theMonthenum.intGets the month-of-year field from 1 to 12.inthashCode()A hash code for this month-day.booleanChecks if this month-day is after the specified month-day.booleanChecks if this month-day is before the specified month-day.booleanisSupported(TemporalField field) Checks if the specified field is supported.booleanisValidYear(int year) Checks if the year is valid for this month-day.static MonthDaynow()Obtains the current month-day from the system clock in the default time-zone.static MonthDayObtains the current month-day from the specified clock.static MonthDayObtains the current month-day from the system clock in the specified time-zone.static MonthDayof(int month, int dayOfMonth) Obtains an instance ofMonthDay.static MonthDayObtains an instance ofMonthDay.static MonthDayparse(CharSequence text) Obtains an instance ofMonthDayfrom a text string such as--12-03.static MonthDayparse(CharSequence text, DateTimeFormatter formatter) Obtains an instance ofMonthDayfrom a text string using a specific formatter.<R> Rquery(TemporalQuery<R> query) Queries this month-day using the specified query.range(TemporalField field) Gets the range of valid values for the specified field.toString()Outputs this month-day as aString, such as--12-03.Returns a copy of thisMonthDaywith the month-of-year altered.withDayOfMonth(int dayOfMonth) Returns a copy of thisMonthDaywith the day-of-month altered.withMonth(int month) Returns a copy of thisMonthDaywith the month-of-year altered.
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Method Details
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now
Obtains the current month-day from the system clock in the default time-zone.This will query the
system clockin 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.
- Returns:
- the current month-day using the system clock and default time-zone, not null
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now
Obtains the current month-day from the system clock in the specified time-zone.This will query the
system clockto 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.
- Parameters:
zone- the zone ID to use, not null- Returns:
- the current month-day using the system clock, not null
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now
Obtains the current month-day from the specified 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.- Parameters:
clock- the clock to use, not null- Returns:
- the current month-day, not null
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of
Obtains an instance ofMonthDay.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.
- Parameters:
month- the month-of-year to represent, not nulldayOfMonth- the day-of-month to represent, from 1 to 31- Returns:
- the month-day, not null
- Throws:
DateTimeException- if the value of any field is out of range, or if the day-of-month is invalid for the month
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of
Obtains an instance ofMonthDay.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.
- Parameters:
month- the month-of-year to represent, from 1 (January) to 12 (December)dayOfMonth- the day-of-month to represent, from 1 to 31- Returns:
- the month-day, not null
- Throws:
DateTimeException- if the value of any field is out of range, or if the day-of-month is invalid for the month
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from
Obtains an instance ofMonthDayfrom a temporal object.This obtains a month-day based on the specified temporal. A
TemporalAccessorrepresents an arbitrary set of date and time information, which this factory converts to an instance ofMonthDay.The conversion extracts the
MONTH_OF_YEARandDAY_OF_MONTHfields. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to aLocalDate.This method matches the signature of the functional interface
TemporalQueryallowing it to be used as a query via method reference,MonthDay::from.- Parameters:
temporal- the temporal object to convert, not null- Returns:
- the month-day, not null
- Throws:
DateTimeException- if unable to convert to aMonthDay
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parse
Obtains an instance ofMonthDayfrom a text string such as--12-03.The string must represent a valid month-day. The format is
--MM-dd.- Parameters:
text- the text to parse such as "--12-03", not null- Returns:
- the parsed month-day, not null
- Throws:
DateTimeParseException- if the text cannot be parsed
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parse
Obtains an instance ofMonthDayfrom a text string using a specific formatter.The text is parsed using the formatter, returning a month-day.
- Parameters:
text- the text to parse, not nullformatter- the formatter to use, not null- Returns:
- the parsed month-day, not null
- Throws:
DateTimeParseException- if the text cannot be parsed
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isSupported
Checks if the specified field is supported.This checks if this month-day can be queried for the specified field. If false, then calling the
rangeandgetmethods will throw an exception.If the field is a
ChronoFieldthen the query is implemented here. The supported fields are:MONTH_OF_YEARYEAR
ChronoFieldinstances will return false.If the field is not a
ChronoField, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor)passingthisas the argument. Whether the field is supported is determined by the field.- Specified by:
isSupportedin interfaceTemporalAccessor- Parameters:
field- the field to check, null returns false- Returns:
- true if the field is supported on this month-day, false if not
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range
Gets the range of valid values for the specified 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
ChronoFieldthen the query is implemented here. Thesupported fieldswill return appropriate range instances. All otherChronoFieldinstances will throw anUnsupportedTemporalTypeException.If the field is not a
ChronoField, then the result of this method is obtained by invokingTemporalField.rangeRefinedBy(TemporalAccessor)passingthisas the argument. Whether the range can be obtained is determined by the field.- Specified by:
rangein interfaceTemporalAccessor- Parameters:
field- the field to query the range for, not null- Returns:
- the range of valid values for the field, not null
- Throws:
DateTimeException- if the range for the field cannot be obtainedUnsupportedTemporalTypeException- if the field is not supported
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get
Gets the value of the specified field from this month-day as anint.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
ChronoFieldthen the query is implemented here. Thesupported fieldswill return valid values based on this month-day. All otherChronoFieldinstances will throw anUnsupportedTemporalTypeException.If the field is not a
ChronoField, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)passingthisas the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
getin interfaceTemporalAccessor- Parameters:
field- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException- 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 anintArithmeticException- if numeric overflow occurs
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getLong
Gets the value of the specified field from this month-day as along.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
ChronoFieldthen the query is implemented here. Thesupported fieldswill return valid values based on this month-day. All otherChronoFieldinstances will throw anUnsupportedTemporalTypeException.If the field is not a
ChronoField, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)passingthisas the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
getLongin interfaceTemporalAccessor- Parameters:
field- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException- if a value for the field cannot be obtainedUnsupportedTemporalTypeException- if the field is not supportedArithmeticException- if numeric overflow occurs
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getMonthValue
public int getMonthValue()Gets the month-of-year field from 1 to 12.This method returns the month as an
intfrom 1 to 12. Application code is frequently clearer if the enumMonthis used by callinggetMonth().- Returns:
- the month-of-year, from 1 to 12
- See Also:
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getMonth
Gets the month-of-year field using theMonthenum.This method returns the enum
Monthfor the month. This avoids confusion as to whatintvalues mean. If you need access to the primitiveintvalue then the enum provides theint value.- Returns:
- the month-of-year, not null
- See Also:
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getDayOfMonth
public int getDayOfMonth()Gets the day-of-month field.This method returns the primitive
intvalue for the day-of-month.- Returns:
- the day-of-month, from 1 to 31
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isValidYear
public boolean isValidYear(int year) Checks if the year is valid for this month-day.This method checks whether this month and day and the input year form a valid date. This can only return false for February 29th.
- Parameters:
year- the year to validate- Returns:
- true if the year is valid for this month-day
- See Also:
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withMonth
Returns a copy of thisMonthDaywith 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.
- Parameters:
month- the month-of-year to set in the returned month-day, from 1 (January) to 12 (December)- Returns:
- a
MonthDaybased on this month-day with the requested month, not null - Throws:
DateTimeException- if the month-of-year value is invalid
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with
Returns a copy of thisMonthDaywith 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.
- Parameters:
month- the month-of-year to set in the returned month-day, not null- Returns:
- a
MonthDaybased on this month-day with the requested month, not null
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withDayOfMonth
Returns a copy of thisMonthDaywith 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.
- Parameters:
dayOfMonth- the day-of-month to set in the return month-day, from 1 to 31- Returns:
- a
MonthDaybased on this month-day with the requested day, not null - Throws:
DateTimeException- if the day-of-month value is invalid, or if the day-of-month is invalid for the month
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query
Queries this month-day using the specified query.This queries this month-day using the specified query strategy object. The
TemporalQueryobject 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 passingthisas the argument.- Specified by:
queryin interfaceTemporalAccessor- Type Parameters:
R- the type of the result- Parameters:
query- the query to invoke, not null- Returns:
- the query result, null may be returned (defined by the query)
- Throws:
DateTimeException- if unable to query (defined by the query)ArithmeticException- if numeric overflow occurs (defined by the query)
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adjustInto
Adjusts the specified temporal object to have this month-day.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, passingChronoField.MONTH_OF_YEARandChronoField.DAY_OF_MONTHas the fields. If the specified temporal object does not use the ISO calendar system then aDateTimeExceptionis 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.
- Specified by:
adjustIntoin interfaceTemporalAdjuster- Parameters:
temporal- the target object to be adjusted, not null- Returns:
- the adjusted object, not null
- Throws:
DateTimeException- if unable to make the adjustmentArithmeticException- if numeric overflow occurs
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format
Formats this month-day using the specified formatter.This month-day will be passed to the formatter to produce a string.
- Parameters:
formatter- the formatter to use, not null- Returns:
- the formatted month-day string, not null
- Throws:
DateTimeException- if an error occurs during printing
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atYear
Combines this month-day with a year to create aLocalDate.This returns a
LocalDateformed 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.
- Parameters:
year- the year to use, from MIN_YEAR to MAX_YEAR- Returns:
- the local date formed from this month-day and the specified year, not null
- Throws:
DateTimeException- if the year is outside the valid range of years
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compareTo
Compares this month-day to another month-day.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.- Specified by:
compareToin interfaceComparable<MonthDay>- Parameters:
other- the other month-day to compare to, not null- Returns:
- the comparator value, that is less than zero if this is before
other, zero if they are equal, greater than zero if this is afterother - See Also:
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isAfter
Checks if this month-day is after the specified month-day.- Parameters:
other- the other month-day to compare to, not null- Returns:
- true if this is after the specified month-day
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isBefore
Checks if this month-day is before the specified month-day.- Parameters:
other- the other month-day to compare to, not null- Returns:
- true if this point is before the specified month-day
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equals
Checks if this month-day is equal to another month-day.The comparison is based on the time-line position of the month-day within a year.
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hashCode
public int hashCode()A hash code for this month-day. -
toString
Outputs this month-day as aString, such as--12-03.The output will be in the format
--MM-dd:
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