Module java.base

Package java.time

Enum Class DayOfWeek

java.lang.Object

java.lang.Enum<DayOfWeek>

java.time.DayOfWeek

All Implemented Interfaces:

Serializable, Comparable<DayOfWeek>, Constable, TemporalAccessor, TemporalAdjuster

public enum DayOfWeek
extends Enum<DayOfWeek>
implements TemporalAccessor, TemporalAdjuster

A day-of-week, such as 'Tuesday'.

DayOfWeek is an enum representing the 7 days of the week - Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.

In addition to the textual enum name, each day-of-week has an int value. The int value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday). It is recommended that applications use the enum rather than the int value to ensure code clarity.

This enum provides access to the localized textual form of the day-of-week. Some locales also assign different numeric values to the days, declaring Sunday to have the value 1, however this class provides no support for this. See WeekFields for localized week-numbering.

Do not use ordinal() to obtain the numeric representation of DayOfWeek. 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 day-of-week concept defined exactly equivalent to the ISO 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
FRIDAY	The singleton instance for the day-of-week of Friday.
MONDAY	The singleton instance for the day-of-week of Monday.
SATURDAY	The singleton instance for the day-of-week of Saturday.
SUNDAY	The singleton instance for the day-of-week of Sunday.
THURSDAY	The singleton instance for the day-of-week of Thursday.
TUESDAY	The singleton instance for the day-of-week of Tuesday.
WEDNESDAY	The singleton instance for the day-of-week of Wednesday.

Method Summary

Modifier and Type	Method	Description
Temporal	adjustInto(Temporal temporal)	Adjusts the specified temporal object to have this day-of-week.
static DayOfWeek	from(TemporalAccessor temporal)	Obtains an instance of DayOfWeek from a temporal object.
int	get(TemporalField field)	Gets the value of the specified field from this day-of-week as an int.
String	getDisplayName(TextStyle style, Locale locale)	Gets the textual representation, such as 'Mon' or 'Friday'.
long	getLong(TemporalField field)	Gets the value of the specified field from this day-of-week as a long.
int	getValue()	Gets the day-of-week int value.
boolean	isSupported(TemporalField field)	Checks if the specified field is supported.
DayOfWeek	minus(long days)	Returns the day-of-week that is the specified number of days before this one.
static DayOfWeek	of(int dayOfWeek)	Obtains an instance of DayOfWeek from an int value.
DayOfWeek	plus(long days)	Returns the day-of-week that is the specified number of days after this one.
<R> R	query(TemporalQuery<R> query)	Queries this day-of-week using the specified query.
ValueRange	range(TemporalField field)	Gets the range of valid values for the specified field.
static DayOfWeek	valueOf(String name)	Returns the enum constant of this class with the specified name.
static DayOfWeek[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods declared in class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods declared in class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

MONDAY

public static final DayOfWeek MONDAY

The singleton instance for the day-of-week of Monday. This has the numeric value of 1.

TUESDAY

public static final DayOfWeek TUESDAY

The singleton instance for the day-of-week of Tuesday. This has the numeric value of 2.

WEDNESDAY

public static final DayOfWeek WEDNESDAY

The singleton instance for the day-of-week of Wednesday. This has the numeric value of 3.

THURSDAY

public static final DayOfWeek THURSDAY

The singleton instance for the day-of-week of Thursday. This has the numeric value of 4.

FRIDAY

public static final DayOfWeek FRIDAY

The singleton instance for the day-of-week of Friday. This has the numeric value of 5.

SATURDAY

public static final DayOfWeek SATURDAY

The singleton instance for the day-of-week of Saturday. This has the numeric value of 6.

SUNDAY

public static final DayOfWeek SUNDAY

The singleton instance for the day-of-week of Sunday. This has the numeric value of 7.

Method Details

values

public static DayOfWeek[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static DayOfWeek valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (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 class has no constant with the specified name

NullPointerException - if the argument is null

of

public static DayOfWeek of(int dayOfWeek)

Obtains an instance of DayOfWeek from an int value.

DayOfWeek is an enum representing the 7 days of the week. This factory allows the enum to be obtained from the int value. The int value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).

Parameters:

dayOfWeek - the day-of-week to represent, from 1 (Monday) to 7 (Sunday)

Returns:

the day-of-week singleton, not null

Throws:

DateTimeException - if the day-of-week is invalid

from

public static DayOfWeek from(TemporalAccessor temporal)

Obtains an instance of DayOfWeek from a temporal object.

This obtains a day-of-week based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of DayOfWeek.

The conversion extracts the DAY_OF_WEEK field.

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, DayOfWeek::from.

Parameters:

temporal - the temporal object to convert, not null

Returns:

the day-of-week, not null

Throws:

DateTimeException - if unable to convert to a DayOfWeek

getValue

public int getValue()

Gets the day-of-week int value.

The values are numbered following the ISO-8601 standard, from 1 (Monday) to 7 (Sunday). See WeekFields.dayOfWeek() for localized week-numbering.

Returns:

the day-of-week, from 1 (Monday) to 7 (Sunday)

getDisplayName

public String getDisplayName(TextStyle style,
 Locale locale)

Gets the textual representation, such as 'Mon' or 'Friday'.

This returns the textual name used to identify the day-of-week, 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 null

locale - the locale to use, not null

Returns:

the text value of the day-of-week, not null

isSupported

public boolean isSupported(TemporalField field)

Checks if the specified field is supported.

This checks if this day-of-week can be queried for the specified field. If false, then calling the range and get methods will throw an exception.

If the field is DAY_OF_WEEK 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.

Specified by:

isSupported in interface TemporalAccessor

Parameters:

field - the field to check, null returns false

Returns:

true if the field is supported on this day-of-week, false if not

range

public ValueRange range(TemporalField field)

Gets the range of valid values for the specified field.

The range object expresses the minimum and maximum valid values for a field. This day-of-week 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 DAY_OF_WEEK then the range of the day-of-week, from 1 to 7, 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.

Specified by:

range in interface TemporalAccessor

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 obtained

UnsupportedTemporalTypeException - if the field is not supported

get

public int get(TemporalField field)

Gets the value of the specified field from this day-of-week as an int.

This queries this day-of-week 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 DAY_OF_WEEK then the value of the day-of-week, from 1 to 7, 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.

Specified by:

get in interface TemporalAccessor

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 field

UnsupportedTemporalTypeException - if the field is not supported or the range of values exceeds an int

ArithmeticException - if numeric overflow occurs

getLong

public long getLong(TemporalField field)

Gets the value of the specified field from this day-of-week as a long.

This queries this day-of-week 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 DAY_OF_WEEK then the value of the day-of-week, from 1 to 7, 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.

Specified by:

getLong in interface TemporalAccessor

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

UnsupportedTemporalTypeException - if the field is not supported

ArithmeticException - if numeric overflow occurs

plus

public DayOfWeek plus(long days)

Returns the day-of-week that is the specified number of days after this one.

The calculation rolls around the end of the week from Sunday to Monday. The specified period may be negative.

This instance is immutable and unaffected by this method call.

Parameters:

days - the days to add, positive or negative

Returns:

the resulting day-of-week, not null

minus

public DayOfWeek minus(long days)

Returns the day-of-week that is the specified number of days before this one.

The calculation rolls around the start of the year from Monday to Sunday. The specified period may be negative.

This instance is immutable and unaffected by this method call.

Parameters:

days - the days to subtract, positive or negative

Returns:

the resulting day-of-week, not null

query

public <R> R query(TemporalQuery<R> query)

Queries this day-of-week using the specified query.

This queries this day-of-week 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.

Specified by:

query in interface TemporalAccessor

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

public Temporal adjustInto(Temporal temporal)

Adjusts the specified temporal object to have this day-of-week.

This returns a temporal object of the same observable type as the input with the day-of-week changed to be the same as this.

The adjustment is equivalent to using Temporal.with(TemporalField, long) passing ChronoField.DAY_OF_WEEK as the field. Note that this adjusts forwards or backwards within a Monday to Sunday week. See WeekFields.dayOfWeek() for localized week start days. See TemporalAdjuster for other adjusters with more control, such as next(MONDAY).

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 = thisDayOfWeek.adjustInto(temporal);
   temporal = temporal.with(thisDayOfWeek);
 

For example, given a date that is a Wednesday, the following are output:

   dateOnWed.with(MONDAY);     // two days earlier
   dateOnWed.with(TUESDAY);    // one day earlier
   dateOnWed.with(WEDNESDAY);  // same date
   dateOnWed.with(THURSDAY);   // one day later
   dateOnWed.with(FRIDAY);     // two days later
   dateOnWed.with(SATURDAY);   // three days later
   dateOnWed.with(SUNDAY);     // four days later
 

This instance is immutable and unaffected by this method call.

Specified by:

adjustInto in interface TemporalAdjuster

Parameters:

temporal - the target object to be adjusted, not null

Returns:

the adjusted object, not null

Throws:

DateTimeException - if unable to make the adjustment

ArithmeticException - if numeric overflow occurs