- All Implemented Interfaces:
Serializable
,Comparable<Month>
,Constable
,TemporalAccessor
,TemporalAdjuster
public enum Month extends Enum<Month> implements TemporalAccessor, TemporalAdjuster
Month
is an enum representing the 12 months of the year -
January, February, March, April, May, June, July, August, September, October,
November and December.
In addition to the textual enum name, each month-of-year has an int
value.
The int
value follows normal usage and the ISO-8601 standard,
from 1 (January) to 12 (December). It is recommended that applications use the enum
rather than the int
value to ensure code clarity.
Do not use ordinal()
to obtain the numeric representation of Month
.
Use getValue()
instead.
This enum represents a common concept that is found in many calendar systems. As such, this enum may be used by any calendar system that has the month-of-year concept defined exactly equivalent to the ISO-8601 calendar system.
- Implementation Requirements:
- This is an immutable and thread-safe enum.
- Since:
- 1.8
-
Nested Class Summary
Nested classes/interfaces declared in class java.lang.Enum
Enum.EnumDesc<E extends Enum<E>>
-
Enum Constant Summary
Enum Constants Enum Constant Description APRIL
The singleton instance for the month of April with 30 days.AUGUST
The singleton instance for the month of August with 31 days.DECEMBER
The singleton instance for the month of December with 31 days.FEBRUARY
The singleton instance for the month of February with 28 days, or 29 in a leap year.JANUARY
The singleton instance for the month of January with 31 days.JULY
The singleton instance for the month of July with 31 days.JUNE
The singleton instance for the month of June with 30 days.MARCH
The singleton instance for the month of March with 31 days.MAY
The singleton instance for the month of May with 31 days.NOVEMBER
The singleton instance for the month of November with 30 days.OCTOBER
The singleton instance for the month of October with 31 days.SEPTEMBER
The singleton instance for the month of September with 30 days. -
Method Summary
Modifier and Type Method Description Temporal
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this month-of-year.int
firstDayOfYear(boolean leapYear)
Gets the day-of-year corresponding to the first day of this month.Month
firstMonthOfQuarter()
Gets the month corresponding to the first month of this quarter.static Month
from(TemporalAccessor temporal)
Obtains an instance ofMonth
from a temporal object.int
get(TemporalField field)
Gets the value of the specified field from this month-of-year as anint
.String
getDisplayName(TextStyle style, Locale locale)
Gets the textual representation, such as 'Jan' or 'December'.long
getLong(TemporalField field)
Gets the value of the specified field from this month-of-year as along
.int
getValue()
Gets the month-of-yearint
value.boolean
isSupported(TemporalField field)
Checks if the specified field is supported.int
length(boolean leapYear)
Gets the length of this month in days.int
maxLength()
Gets the maximum length of this month in days.int
minLength()
Gets the minimum length of this month in days.Month
minus(long months)
Returns the month-of-year that is the specified number of months before this one.static Month
of(int month)
Obtains an instance ofMonth
from anint
value.Month
plus(long months)
Returns the month-of-year that is the specified number of months after this one.<R> R
query(TemporalQuery<R> query)
Queries this month-of-year using the specified query.ValueRange
range(TemporalField field)
Gets the range of valid values for the specified field.static Month
valueOf(String name)
Returns the enum constant of this type with the specified name.static Month[]
values()
Returns an array containing the constants of this enum type, in the order they are declared.
-
Enum Constant Details
-
JANUARY
The singleton instance for the month of January with 31 days. This has the numeric value of1
. -
FEBRUARY
The singleton instance for the month of February with 28 days, or 29 in a leap year. This has the numeric value of2
. -
MARCH
The singleton instance for the month of March with 31 days. This has the numeric value of3
. -
APRIL
The singleton instance for the month of April with 30 days. This has the numeric value of4
. -
MAY
The singleton instance for the month of May with 31 days. This has the numeric value of5
. -
JUNE
The singleton instance for the month of June with 30 days. This has the numeric value of6
. -
JULY
The singleton instance for the month of July with 31 days. This has the numeric value of7
. -
AUGUST
The singleton instance for the month of August with 31 days. This has the numeric value of8
. -
SEPTEMBER
The singleton instance for the month of September with 30 days. This has the numeric value of9
. -
OCTOBER
The singleton instance for the month of October with 31 days. This has the numeric value of10
. -
NOVEMBER
The singleton instance for the month of November with 30 days. This has the numeric value of11
. -
DECEMBER
The singleton instance for the month of December with 31 days. This has the numeric value of12
.
-
-
Method Details
-
values
Returns an array containing the constants of this enum type, in the order they are declared.- Returns:
- an array containing the constants of this enum type, in the order they are declared
-
valueOf
Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)- Parameters:
name
- the name of the enum constant to be returned.- Returns:
- the enum constant with the specified name
- Throws:
IllegalArgumentException
- if this enum type has no constant with the specified nameNullPointerException
- if the argument is null
-
of
Obtains an instance ofMonth
from anint
value.Month
is an enum representing the 12 months of the year. This factory allows the enum to be obtained from theint
value. Theint
value follows the ISO-8601 standard, from 1 (January) to 12 (December).- Parameters:
month
- the month-of-year to represent, from 1 (January) to 12 (December)- Returns:
- the month-of-year, not null
- Throws:
DateTimeException
- if the month-of-year is invalid
-
from
Obtains an instance ofMonth
from a temporal object.This obtains a month based on the specified temporal. A
TemporalAccessor
represents an arbitrary set of date and time information, which this factory converts to an instance ofMonth
.The conversion extracts the
MONTH_OF_YEAR
field. 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
TemporalQuery
allowing it to be used as a query via method reference,Month::from
.- Parameters:
temporal
- the temporal object to convert, not null- Returns:
- the month-of-year, not null
- Throws:
DateTimeException
- if unable to convert to aMonth
-
getValue
public int getValue()Gets the month-of-yearint
value.The values are numbered following the ISO-8601 standard, from 1 (January) to 12 (December).
- Returns:
- the month-of-year, from 1 (January) to 12 (December)
-
getDisplayName
Gets the textual representation, such as 'Jan' or 'December'.This returns the textual name used to identify the month-of-year, suitable for presentation to the user. The parameters control the style of the returned text and the locale.
If no textual mapping is found then the
numeric value
is returned.- Parameters:
style
- the length of the text required, not nulllocale
- the locale to use, not null- Returns:
- the text value of the month-of-year, not null
-
isSupported
Checks if the specified field is supported.This checks if this month-of-year can be queried for the specified field. If false, then calling the
range
andget
methods will throw an exception.If the field is
MONTH_OF_YEAR
then this method returns true. All otherChronoField
instances will return false.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor)
passingthis
as the argument. Whether the field is supported is determined by the field.- Specified by:
isSupported
in interfaceTemporalAccessor
- Parameters:
field
- the field to check, null returns false- Returns:
- true if the field is supported on this month-of-year, false if not
-
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 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
MONTH_OF_YEAR
then the range of the month-of-year, from 1 to 12, will be returned. All otherChronoField
instances will throw anUnsupportedTemporalTypeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.rangeRefinedBy(TemporalAccessor)
passingthis
as the argument. Whether the range can be obtained is determined by the field.- Specified by:
range
in 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
-
get
Gets the value of the specified field from this month-of-year as anint
.This queries this month 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
MONTH_OF_YEAR
then the value of the month-of-year, from 1 to 12, will be returned. All otherChronoField
instances will throw anUnsupportedTemporalTypeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
get
in interfaceTemporalAccessor
- Parameters:
field
- the field to get, not null- Returns:
- the value for the field, within the valid range of values
- 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 anint
ArithmeticException
- if numeric overflow occurs
-
getLong
Gets the value of the specified field from this month-of-year as along
.This queries this month 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
MONTH_OF_YEAR
then the value of the month-of-year, from 1 to 12, will be returned. All otherChronoField
instances will throw anUnsupportedTemporalTypeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
getLong
in 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
-
plus
Returns the month-of-year that is the specified number of months after this one.The calculation rolls around the end of the year from December to January. The specified period may be negative.
This instance is immutable and unaffected by this method call.
- Parameters:
months
- the months to add, positive or negative- Returns:
- the resulting month, not null
-
minus
Returns the month-of-year that is the specified number of months before this one.The calculation rolls around the start of the year from January to December. The specified period may be negative.
This instance is immutable and unaffected by this method call.
- Parameters:
months
- the months to subtract, positive or negative- Returns:
- the resulting month, not null
-
length
public int length(boolean leapYear)Gets the length of this month in days.This takes a flag to determine whether to return the length for a leap year or not.
February has 28 days in a standard year and 29 days in a leap year. April, June, September and November have 30 days. All other months have 31 days.
- Parameters:
leapYear
- true if the length is required for a leap year- Returns:
- the length of this month in days, from 28 to 31
-
minLength
public int minLength()Gets the minimum length of this month in days.February has a minimum length of 28 days. April, June, September and November have 30 days. All other months have 31 days.
- Returns:
- the minimum length of this month in days, from 28 to 31
-
maxLength
public int maxLength()Gets the maximum length of this month in days.February has a maximum length of 29 days. April, June, September and November have 30 days. All other months have 31 days.
- Returns:
- the maximum length of this month in days, from 29 to 31
-
firstDayOfYear
public int firstDayOfYear(boolean leapYear)Gets the day-of-year corresponding to the first day of this month.This returns the day-of-year that this month begins on, using the leap year flag to determine the length of February.
- Parameters:
leapYear
- true if the length is required for a leap year- Returns:
- the day of year corresponding to the first day of this month, from 1 to 336
-
firstMonthOfQuarter
Gets the month corresponding to the first month of this quarter.The year can be divided into four quarters. This method returns the first month of the quarter for the base month. January, February and March return January. April, May and June return April. July, August and September return July. October, November and December return October.
- Returns:
- the first month of the quarter corresponding to this month, not null
-
query
Queries this month-of-year using the specified query.This queries this month-of-year 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 passingthis
as the argument.- Specified by:
query
in 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)
-
adjustInto
Adjusts the specified temporal object to have this month-of-year.This returns a temporal object of the same observable type as the input with the month-of-year changed to be the same as this.
The adjustment is equivalent to using
Temporal.with(TemporalField, long)
passingChronoField.MONTH_OF_YEAR
as the field. If the specified temporal object does not use the ISO calendar system then aDateTimeException
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 = thisMonth.adjustInto(temporal); temporal = temporal.with(thisMonth);
For example, given a date in May, the following are output:
dateInMay.with(JANUARY); // four months earlier dateInMay.with(APRIL); // one months earlier dateInMay.with(MAY); // same date dateInMay.with(JUNE); // one month later dateInMay.with(DECEMBER); // seven months later
This instance is immutable and unaffected by this method call.
- Specified by:
adjustInto
in 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
-