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 * file:
 *
 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
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package java.time;

import static java.time.temporal.ChronoField.DAY_OF_WEEK;
import static java.time.temporal.ChronoUnit.DAYS;

import java.time.format.DateTimeFormatterBuilder;
import java.time.format.TextStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.time.temporal.WeekFields;
import java.util.Locale;


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
/**
 * A day-of-week, such as 'Tuesday'.
 * <p>
 * {@code DayOfWeek} is an enum representing the 7 days of the week -
 * Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.
 * <p>
 * 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.
 * <p>
 * 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.
 * <p>
 * <b>Do not use {@code ordinal()} to obtain the numeric representation of {@code DayOfWeek}.
 * Use {@code getValue()} instead.</b>
 * <p>
 * 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 1. 
/**
     * 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 2. 
/**
     * 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 3. 
/**
     * 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 4. 
/**
     * 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 5. 
/**
     * 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 6. 
/**
     * 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 7. 
/**
     * 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 cache of all the constants.
     */
    private static final DayOfWeek[] ENUMS = DayOfWeek.values();

    //-----------------------------------------------------------------------
    
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). 
Params:
  • dayOfWeek –  the day-of-week to represent, from 1 (Monday) to 7 (Sunday)
Throws:
Returns:the day-of-week singleton, not null
/**
     * Obtains an instance of {@code DayOfWeek} from an {@code int} value.
     * <p>
     * {@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 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. 
Params:
  • temporal –  the temporal object to convert, not null
Throws:
Returns:the day-of-week, not null
/**
     * Obtains an instance of {@code DayOfWeek} from a temporal object.
     * <p>
     * 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}.
     * <p>
     * The conversion extracts the {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} field.
     * <p>
     * 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 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)
/**
     * Gets the day-of-week {@code int} value.
     * <p>
     * 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 numeric value is returned. 
Params:
  • 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
/**
     * Gets the textual representation, such as 'Mon' or 'Friday'.
     * <p>
     * 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.
     * <p>
     * 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 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. 
Params:
  • field –  the field to check, null returns false
Returns:true if the field is supported on this day-of-week, false if not
/**
     * Checks if the specified field is supported.
     * <p>
     * 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.
     * <p>
     * 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.
     * <p>
     * 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 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. 
Params:
  • field –  the field to query the range for, not null
Throws:
Returns:the range of valid values for the field, not null
/**
     * Gets the range of valid values for the specified field.
     * <p>
     * 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.
     * <p>
     * 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}.
     * <p>
     * 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 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. 
Params:
  • field –  the field to get, not null
Throws:
Returns:the value for the field, within the valid range of values
/**
     * Gets the value of the specified field from this day-of-week as an {@code int}.
     * <p>
     * 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.
     * <p>
     * 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}.
     * <p>
     * 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 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. 
Params:
  • field –  the field to get, not null
Throws:
Returns:the value for the field
/**
     * Gets the value of the specified field from this day-of-week as a {@code long}.
     * <p>
     * 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.
     * <p>
     * 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}.
     * <p>
     * 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.

Params:
  • days –  the days to add, positive or negative
Returns:the resulting day-of-week, not null
/**
     * Returns the day-of-week that is the specified number of days after this one.
     * <p>
     * The calculation rolls around the end of the week from Sunday to Monday.
     * The specified period may be negative.
     * <p>
     * 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.

Params:
  • days –  the days to subtract, positive or negative
Returns:the resulting day-of-week, not null
/**
     * Returns the day-of-week that is the specified number of days before this one.
     * <p>
     * The calculation rolls around the start of the year from Monday to Sunday.
     * The specified period may be negative.
     * <p>
     * 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 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. 
Params:
  • query –  the query to invoke, not null
Type parameters:
  • <R> – the type of the result
Throws:
Returns:the query result, null may be returned (defined by the query)
/**
     * Queries this day-of-week using the specified query.
     * <p>
     * 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.
     * <p>
     * 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 <R> the type of the result
     * @param query  the query to invoke, not null
     * @return the query result, null may be returned (defined by the query)
     * @throws DateTimeException if unable to query (defined by the query)
     * @throws ArithmeticException if numeric overflow occurs (defined by the query)
     */
    @SuppressWarnings("unchecked")
    @Override
    public <R> R query(TemporalQuery<R> query) {
        if (query == TemporalQueries.precision()) {
            return (R) DAYS;
        }
        return TemporalAccessor.super.query(query);
    }

    
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.

Params:
  • temporal –  the target object to be adjusted, not null
Throws:
Returns:the adjusted object, not null
/**
     * Adjusts the specified temporal object to have this day-of-week.
     * <p>
     * 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.
     * <p>
     * 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)}.
     * <p>
     * In most cases, it is clearer to reverse the calling pattern by using
     * {@link Temporal#with(TemporalAdjuster)}:
     * <pre>
     *   // these two lines are equivalent, but the second approach is recommended
     *   temporal = thisDayOfWeek.adjustInto(temporal);
     *   temporal = temporal.with(thisDayOfWeek);
     * </pre>
     * <p>
     * For example, given a date that is a Wednesday, the following are output:
     * <pre>
     *   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
     * </pre>
     * <p>
     * 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());
    }

}