Module java.base
Package java.time

Enum DayOfWeek

  • All Implemented Interfaces:
    Serializable, Comparable<DayOfWeek>, 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

    • Enum Constant Detail

      • 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 Detail

      • values

        public static DayOfWeek[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: 
        for (DayOfWeek c : DayOfWeek.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static DayOfWeek valueOf​(String name)
        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 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