+ * {@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. + * + *
+ * {@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. + *
+ * A {@code TemporalAccessor} represents some form of date and time information. + * This factory converts the arbitrary temporal object 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; + } + return of(temporal.get(DAY_OF_WEEK)); + } + + //----------------------------------------------------------------------- + /** + * 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 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. + * The parameters control the length 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 getText(TextStyle style, Locale locale) { + return new DateTimeFormatterBuilder().appendText(DAY_OF_WEEK, style).toFormatter(locale).print(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.doIsSupported(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.doIsSupported(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 a {@code DateTimeException}. + *
+ * If the field is not a {@code ChronoField}, then the result of this method + * is obtained by invoking {@code TemporalField.doRange(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 + */ + @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 for 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 a {@code DateTimeException}. + *
+ * If the field is not a {@code ChronoField}, then the result of this method + * is obtained by invoking {@code TemporalField.doGet(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 + * @throws DateTimeException if the range of valid values for the field exceeds an {@code int} + * @throws DateTimeException if the value is outside the range of valid values for the field + * @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 for 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 a {@code DateTimeException}. + *
+ * If the field is not a {@code ChronoField}, then the result of this method + * is obtained by invoking {@code TemporalField.doGet(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 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 DateTimeException("Unsupported field: " + field.getName()); + } + return field.doGet(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 WeekFields#dayOfWeek} for localized week start days.
+ * See {@link java.time.temporal.Adjusters Adjusters} 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
+ *
+ *