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.
Enum.EnumDesc<E extends Enum<E>>
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. |
Modifier and Type | Method | Description |
---|---|---|
Temporal |
adjustInto |
Adjusts the specified temporal object to have this month-of-year. |
int |
firstDayOfYear |
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 |
Obtains an instance of Month from a temporal object. |
int |
get |
Gets the value of the specified field from this month-of-year as an int . |
String |
getDisplayName |
Gets the textual representation, such as 'Jan' or 'December'. |
long |
getLong |
Gets the value of the specified field from this month-of-year as a long . |
int |
getValue() |
Gets the month-of-year int value. |
boolean |
isSupported |
Checks if the specified field is supported. |
int |
length |
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 |
Returns the month-of-year that is the specified number of months before this one. |
static Month |
of |
Obtains an instance of Month from an int value. |
Month |
plus |
Returns the month-of-year that is the specified number of months after this one. |
<R> R |
query |
Queries this month-of-year using the specified query. |
ValueRange |
range |
Gets the range of valid values for the specified field. |
static Month |
valueOf |
Returns the enum constant of this class with the specified name. |
static Month[] |
values() |
Returns an array containing the constants of this enum class, in the order they are declared. |
public static final Month JANUARY
1
.public static final Month FEBRUARY
2
.public static final Month MARCH
3
.public static final Month APRIL
4
.public static final Month MAY
5
.public static final Month JUNE
6
.public static final Month JULY
7
.public static final Month AUGUST
8
.public static final Month SEPTEMBER
9
.public static final Month OCTOBER
10
.public static final Month NOVEMBER
11
.public static final Month DECEMBER
12
.public static Month[] values()
public static Month valueOf(String name)
name
- the name of the enum constant to be returned.IllegalArgumentException
- if this enum class has no constant with the specified nameNullPointerException
- if the argument is nullpublic static Month of(int month)
Month
from an int
value. Month
is an enum representing the 12 months of the year. This factory allows the enum to be obtained from the int
value. The int
value follows the ISO-8601 standard, from 1 (January) to 12 (December).
month
- the month-of-year to represent, from 1 (January) to 12 (December)DateTimeException
- if the month-of-year is invalidpublic static Month from(TemporalAccessor temporal)
Month
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 of Month
.
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 a LocalDate
.
This method matches the signature of the functional interface TemporalQuery
allowing it to be used as a query via method reference, Month::from
.
temporal
- the temporal object to convert, not nullDateTimeException
- if unable to convert to a Month
public int getValue()
int
value. The values are numbered following the ISO-8601 standard, from 1 (January) to 12 (December).
public String getDisplayName(TextStyle style, Locale locale)
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.
style
- the length of the text required, not nulllocale
- the locale to use, not nullpublic boolean isSupported(TemporalField field)
This checks if this month-of-year can be queried for the specified field. If false, then calling the range
and get
methods will throw an exception.
If the field is MONTH_OF_YEAR
then this method returns true. All other 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 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 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 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 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 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 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 Month plus(long months)
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.
months
- the months to add, positive or negativepublic Month minus(long months)
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.
months
- the months to subtract, positive or negativepublic int length(boolean leapYear)
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.
leapYear
- true if the length is required for a leap yearpublic int minLength()
February has a minimum length of 28 days. April, June, September and November have 30 days. All other months have 31 days.
public int maxLength()
February has a maximum length of 29 days. April, June, September and November have 30 days. All other months have 31 days.
public int firstDayOfYear(boolean leapYear)
This returns the day-of-year that this month begins on, using the leap year flag to determine the length of February.
leapYear
- true if the length is required for a leap yearpublic Month firstMonthOfQuarter()
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.
public <R> R query(TemporalQuery<R> 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 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-of-year changed to be the same as this.
The adjustment is equivalent to using Temporal.with(TemporalField, long)
passing ChronoField.MONTH_OF_YEAR
as the field. 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 = 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.
adjustInto
in interface TemporalAdjuster
temporal
- the target object to be adjusted, not nullDateTimeException
- if unable to make the adjustmentArithmeticException
- if numeric overflow occurs
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