* {@code 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 {@code int} value. * The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday). * It is recommended that applications use the enum rather than the {@code 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 {@link WeekFields} for localized week-numbering. *
* Do not use {@code ordinal()} to obtain the numeric representation of {@code DayOfWeek}. * Use {@code 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. * * @implSpec * This is an immutable and thread-safe enum. * * @since 1.8 */ public enum DayOfWeek implements TemporalAccessor, TemporalAdjuster { /** * The singleton instance for the day-of-week of Monday. * This has the numeric value of {@code 1}. */ MONDAY, /** * The singleton instance for the day-of-week of Tuesday. * This has the numeric value of {@code 2}. */ TUESDAY, /** * The singleton instance for the day-of-week of Wednesday. * This has the numeric value of {@code 3}. */ WEDNESDAY, /** * The singleton instance for the day-of-week of Thursday. * This has the numeric value of {@code 4}. */ THURSDAY, /** * The singleton instance for the day-of-week of Friday. * This has the numeric value of {@code 5}. */ FRIDAY, /** * The singleton instance for the day-of-week of Saturday. * This has the numeric value of {@code 6}. */ SATURDAY, /** * The singleton instance for the day-of-week of Sunday. * This has the numeric value of {@code 7}. */ SUNDAY; /** * Private cache of all the constants. */ private static final DayOfWeek[] ENUMS = DayOfWeek.values(); //----------------------------------------------------------------------- /** * Obtains an instance of {@code DayOfWeek} from an {@code int} value. *
* {@code DayOfWeek} is an enum representing the 7 days of the week. * This factory allows the enum to be obtained from the {@code int} value. * The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday). * * @param dayOfWeek the day-of-week to represent, from 1 (Monday) to 7 (Sunday) * @return the day-of-week singleton, not null * @throws DateTimeException if the day-of-week is invalid */ public static DayOfWeek of(int dayOfWeek) { if (dayOfWeek < 1 || dayOfWeek > 7) { throw new DateTimeException("Invalid value for DayOfWeek: " + dayOfWeek); } return ENUMS[dayOfWeek - 1]; } //----------------------------------------------------------------------- /** * Obtains an instance of {@code DayOfWeek} from a temporal object. *
* This obtains a day-of-week based on the specified temporal. * A {@code TemporalAccessor} represents an arbitrary set of date and time information, * which this factory converts to an instance of {@code DayOfWeek}. *
* The conversion extracts the {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} field. *
* This method matches the signature of the functional interface {@link TemporalQuery} * allowing it to be used as a query via method reference, {@code DayOfWeek::from}. * * @param temporal the temporal object to convert, not null * @return the day-of-week, not null * @throws DateTimeException if unable to convert to a {@code DayOfWeek} */ public static DayOfWeek from(TemporalAccessor temporal) { if (temporal instanceof DayOfWeek) { return (DayOfWeek) temporal; } try { return of(temporal.get(DAY_OF_WEEK)); } catch (DateTimeException ex) { throw new DateTimeException("Unable to obtain DayOfWeek from TemporalAccessor: " + temporal + " of type " + temporal.getClass().getName(), ex); } } //----------------------------------------------------------------------- /** * Gets the day-of-week {@code int} value. *
* The values are numbered following the ISO-8601 standard, from 1 (Monday) to 7 (Sunday). * See {@link java.time.temporal.WeekFields#dayOfWeek()} for localized week-numbering. * * @return the day-of-week, from 1 (Monday) to 7 (Sunday) */ public int getValue() { return ordinal() + 1; } //----------------------------------------------------------------------- /** * 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 {@link #getValue() numeric value} is returned. * * @param style the length of the text required, not null * @param locale the locale to use, not null * @return the text value of the day-of-week, not null */ public String getDisplayName(TextStyle style, Locale locale) { return new DateTimeFormatterBuilder().appendText(DAY_OF_WEEK, style).toFormatter(locale).format(this); } //----------------------------------------------------------------------- /** * 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 {@link #range(TemporalField) range} and * {@link #get(TemporalField) get} methods will throw an exception. *
* If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then * this method returns true. * All other {@code ChronoField} instances will return false. *
* If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} * passing {@code this} as the argument. * Whether the field is supported is determined by the field. * * @param field the field to check, null returns false * @return true if the field is supported on this day-of-week, false if not */ @Override public boolean isSupported(TemporalField field) { if (field instanceof ChronoField) { return field == DAY_OF_WEEK; } return field != null && field.isSupportedBy(this); } /** * 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 {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the * range of the day-of-week, from 1 to 7, will be returned. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. *
* If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} * passing {@code this} as the argument. * Whether the range can be obtained is determined by the field. * * @param field the field to query the range for, not null * @return the range of valid values for the field, not null * @throws DateTimeException if the range for the field cannot be obtained * @throws UnsupportedTemporalTypeException if the field is not supported */ @Override public ValueRange range(TemporalField field) { if (field == DAY_OF_WEEK) { return field.range(); } return TemporalAccessor.super.range(field); } /** * Gets the value of the specified field from this day-of-week as an {@code 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 {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the * value of the day-of-week, from 1 to 7, will be returned. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. *
* If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} * passing {@code this} as the argument. Whether the value can be obtained, * and what the value represents, is determined by the field. * * @param field the field to get, not null * @return 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 * @throws UnsupportedTemporalTypeException if the field is not supported or * the range of values exceeds an {@code int} * @throws ArithmeticException if numeric overflow occurs */ @Override public int get(TemporalField field) { if (field == DAY_OF_WEEK) { return getValue(); } return TemporalAccessor.super.get(field); } /** * Gets the value of the specified field from this day-of-week as a {@code 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 {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the * value of the day-of-week, from 1 to 7, will be returned. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. *
* If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} * passing {@code this} as the argument. Whether the value can be obtained, * and what the value represents, is determined by the field. * * @param field the field to get, not null * @return the value for the field * @throws DateTimeException if a value for the field cannot be obtained * @throws UnsupportedTemporalTypeException if the field is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public long getLong(TemporalField field) { if (field == DAY_OF_WEEK) { return getValue(); } else if (field instanceof ChronoField) { throw new UnsupportedTemporalTypeException("Unsupported field: " + field); } return field.getFrom(this); } //----------------------------------------------------------------------- /** * 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. * * @param days the days to add, positive or negative * @return the resulting day-of-week, not null */ public DayOfWeek plus(long days) { int amount = (int) (days % 7); return ENUMS[(ordinal() + (amount + 7)) % 7]; } /** * 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. * * @param days the days to subtract, positive or negative * @return the resulting day-of-week, not null */ public DayOfWeek minus(long days) { return plus(-(days % 7)); } //----------------------------------------------------------------------- /** * Queries this day-of-week using the specified query. *
* This queries this day-of-week using the specified query strategy object. * The {@code 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
* {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
* specified query passing {@code this} as the argument.
*
* @param
* 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 {@link Temporal#with(TemporalField, long)}
* passing {@link ChronoField#DAY_OF_WEEK} as the field.
* Note that this adjusts forwards or backwards within a Monday to Sunday week.
* See {@link java.time.temporal.WeekFields#dayOfWeek()} for localized week start days.
* See {@code TemporalAdjuster} for other adjusters with more control,
* such as {@code next(MONDAY)}.
*
* In most cases, it is clearer to reverse the calling pattern by using
* {@link Temporal#with(TemporalAdjuster)}:
*
* For example, given a date that is a Wednesday, the following are output:
*
* This instance is immutable and unaffected by this method call.
*
* @param temporal the target object to be adjusted, not null
* @return the adjusted object, not null
* @throws DateTimeException if unable to make the adjustment
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public Temporal adjustInto(Temporal temporal) {
return temporal.with(DAY_OF_WEEK, getValue());
}
}
* // these two lines are equivalent, but the second approach is recommended
* temporal = thisDayOfWeek.adjustInto(temporal);
* temporal = temporal.with(thisDayOfWeek);
*
*
* 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
*
*