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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

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 * modification, are permitted provided that the following conditions are met:

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package java.time;

import static java.time.temporal.ChronoField.MONTH_OF_YEAR;

import static java.time.temporal.ChronoUnit.MONTHS;

import java.time.chrono.Chronology;

import java.time.chrono.IsoChronology;

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.util.Locale;

/**

 * A month-of-year, such as 'July'.

 * <p>

 * {@code Month} is an enum representing the 12 months of the year -

 * January, February, March, April, May, June, July, August, September, October,

 * November and December.

 * <p>

 * In addition to the textual enum name, each month-of-year has an {@code int} value.

 * The {@code int} value follows normal usage and the ISO-8601 standard,

 * from 1 (January) to 12 (December). It is recommended that applications use the enum

 * rather than the {@code int} value to ensure code clarity.

 * <p>

 * <b>Do not use {@code ordinal()} to obtain the numeric representation of {@code Month}.

 * 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 month-of-year

 * concept defined exactly equivalent to the ISO-8601 calendar system.

 *

 * @implSpec

 * This is an immutable and thread-safe enum.

 *

 * @since 1.8

 */

public enum Month implements TemporalAccessor, TemporalAdjuster {

    /**

     * The singleton instance for the month of January with 31 days.

     * This has the numeric value of {@code 1}.

     */

    JANUARY,

    /**

     * The singleton instance for the month of February with 28 days, or 29 in a leap year.

     * This has the numeric value of {@code 2}.

     */

    FEBRUARY,

    /**

     * The singleton instance for the month of March with 31 days.

     * This has the numeric value of {@code 3}.

     */

    MARCH,

    /**

     * The singleton instance for the month of April with 30 days.

     * This has the numeric value of {@code 4}.

     */

    APRIL,

    /**

     * The singleton instance for the month of May with 31 days.

     * This has the numeric value of {@code 5}.

     */

    MAY,

    /**

     * The singleton instance for the month of June with 30 days.

     * This has the numeric value of {@code 6}.

     */

    JUNE,

    /**

     * The singleton instance for the month of July with 31 days.

     * This has the numeric value of {@code 7}.

     */

    JULY,

    /**

     * The singleton instance for the month of August with 31 days.

     * This has the numeric value of {@code 8}.

     */

    AUGUST,

    /**

     * The singleton instance for the month of September with 30 days.

     * This has the numeric value of {@code 9}.

     */

    SEPTEMBER,

    /**

     * The singleton instance for the month of October with 31 days.

     * This has the numeric value of {@code 10}.

     */

    OCTOBER,

    /**

     * The singleton instance for the month of November with 30 days.

     * This has the numeric value of {@code 11}.

     */

    NOVEMBER,

    /**

     * The singleton instance for the month of December with 31 days.

     * This has the numeric value of {@code 12}.

     */

    DECEMBER;

    /**

     * Private cache of all the constants.

     */

    private static final Month[] ENUMS = Month.values();

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code Month} from an {@code int} value.

     * <p>

     * {@code Month} is an enum representing the 12 months of the year.

     * This factory allows the enum to be obtained from the {@code int} value.

     * The {@code int} value follows the ISO-8601 standard, from 1 (January) to 12 (December).

     *

     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)

     * @return the month-of-year, not null

     * @throws DateTimeException if the month-of-year is invalid

     */

    public static Month of(int month) {

        if (month < 1 || month > 12) {

            throw new DateTimeException("Invalid value for MonthOfYear: " + month);

        }

        return ENUMS[month - 1];

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code Month} from a temporal object.

     * <p>

     * This obtains a month 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 Month}.

     * <p>

     * The conversion extracts the {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} field.

     * The extraction is only permitted if the temporal object has an ISO

     * chronology, or can be converted to a {@code LocalDate}.

     * <p>

     * This method matches the signature of the functional interface {@link TemporalQuery}

     * allowing it to be used in queries via method reference, {@code Month::from}.

     *

     * @param temporal  the temporal object to convert, not null

     * @return the month-of-year, not null

     * @throws DateTimeException if unable to convert to a {@code Month}

     */

    public static Month from(TemporalAccessor temporal) {

        if (temporal instanceof Month) {

            return (Month) temporal;

        }

        try {

            if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) {

                temporal = LocalDate.from(temporal);

            }

            return of(temporal.get(MONTH_OF_YEAR));

        } catch (DateTimeException ex) {

            throw new DateTimeException("Unable to obtain Month from TemporalAccessor: " +

                    temporal + " of type " + temporal.getClass().getName(), ex);

        }

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the month-of-year {@code int} value.

     * <p>

     * The values are numbered following the ISO-8601 standard,

     * from 1 (January) to 12 (December).

     *

     * @return the month-of-year, from 1 (January) to 12 (December)

     */

    public int getValue() {

        return ordinal() + 1;

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the textual representation, such as 'Jan' or 'December'.

     * <p>

     * This returns the textual name used to identify the month-of-year,

     * 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 month-of-year, not null

     */

    public String getDisplayName(TextStyle style, Locale locale) {

        return new DateTimeFormatterBuilder().appendText(MONTH_OF_YEAR, style).toFormatter(locale).format(this);

    }

    //-----------------------------------------------------------------------

    /**

     * Checks if the specified field is supported.

     * <p>

     * This checks if this month-of-year 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#MONTH_OF_YEAR MONTH_OF_YEAR} 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 month-of-year, false if not

     */

    @Override

    public boolean isSupported(TemporalField field) {

        if (field instanceof ChronoField) {

            return field == MONTH_OF_YEAR;

        }

        return field != null && field.isSupportedBy(this);

    }

    /**

     * 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 month 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#MONTH_OF_YEAR MONTH_OF_YEAR} then the

     * range of the month-of-year, from 1 to 12, 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 == MONTH_OF_YEAR) {

            return field.range();

        }

        return TemporalAccessor.super.range(field);

    }

    /**

     * Gets the value of the specified field from this month-of-year as an {@code int}.

     * <p>

     * This queries this month 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.

     * <p>

     * If the field is {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} then the

     * value of the month-of-year, from 1 to 12, 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 == MONTH_OF_YEAR) {

            return getValue();

        }

        return TemporalAccessor.super.get(field);

    }

    /**

     * Gets the value of the specified field from this month-of-year as a {@code long}.

     * <p>

     * This queries this month 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.

     * <p>

     * If the field is {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} then the

     * value of the month-of-year, from 1 to 12, 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 == MONTH_OF_YEAR) {

            return getValue();

        } else if (field instanceof ChronoField) {

            throw new UnsupportedTemporalTypeException("Unsupported field: " + field);

        }

        return field.getFrom(this);

    }

    //-----------------------------------------------------------------------

    /**

     * Returns the month-of-year that is the specified number of quarters after this one.

     * <p>

     * The calculation rolls around the end of the year from December to January.

     * The specified period may be negative.

     * <p>

     * This instance is immutable and unaffected by this method call.

     *

     * @param months  the months to add, positive or negative

     * @return the resulting month, not null

     */

    public Month plus(long months) {

        int amount = (int) (months % 12);

        return ENUMS[(ordinal() + (amount + 12)) % 12];

    }

    /**

     * Returns the month-of-year that is the specified number of months before this one.

     * <p>

     * The calculation rolls around the start of the year from January to December.

     * The specified period may be negative.

     * <p>

     * This instance is immutable and unaffected by this method call.

     *

     * @param months  the months to subtract, positive or negative

     * @return the resulting month, not null

     */

    public Month minus(long months) {

        return plus(-(months % 12));

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the length of this month in days.

     * <p>

     * This takes a flag to determine whether to return the length for a leap year or not.

     * <p>

     * February has 28 days in a standard year and 29 days in a leap year.

     * April, June, September and November have 30 days.

     * All other months have 31 days.

     *

     * @param leapYear  true if the length is required for a leap year

     * @return the length of this month in days, from 28 to 31

     */

    public int length(boolean leapYear) {

        switch (this) {

            case FEBRUARY:

                return (leapYear ? 29 : 28);

            case APRIL:

            case JUNE:

            case SEPTEMBER:

            case NOVEMBER:

                return 30;

            default:

                return 31;

        }

    }

    /**

     * Gets the minimum length of this month in days.

     * <p>

     * February has a minimum length of 28 days.

     * April, June, September and November have 30 days.

     * All other months have 31 days.

     *

     * @return the minimum length of this month in days, from 28 to 31

     */

    public int minLength() {

        switch (this) {

            case FEBRUARY:

                return 28;

            case APRIL:

            case JUNE:

            case SEPTEMBER:

            case NOVEMBER:

                return 30;

            default:

                return 31;

        }

    }

    /**

     * Gets the maximum length of this month in days.

     * <p>

     * February has a maximum length of 29 days.

     * April, June, September and November have 30 days.

     * All other months have 31 days.

     *

     * @return the maximum length of this month in days, from 29 to 31

     */

    public int maxLength() {

        switch (this) {

            case FEBRUARY:

                return 29;

            case APRIL:

            case JUNE:

            case SEPTEMBER:

            case NOVEMBER:

                return 30;

            default:

                return 31;

        }

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the day-of-year corresponding to the first day of this month.

     * <p>

     * This returns the day-of-year that this month begins on, using the leap

     * year flag to determine the length of February.

     *

     * @param leapYear  true if the length is required for a leap year

     * @return the day of year corresponding to the first day of this month, from 1 to 336

     */

    public int firstDayOfYear(boolean leapYear) {

        int leap = leapYear ? 1 : 0;

        switch (this) {

            case JANUARY:

                return 1;

            case FEBRUARY:

                return 32;

            case MARCH:

                return 60 + leap;

            case APRIL:

                return 91 + leap;

            case MAY:

                return 121 + leap;

            case JUNE:

                return 152 + leap;

            case JULY:

                return 182 + leap;

            case AUGUST:

                return 213 + leap;

            case SEPTEMBER:

                return 244 + leap;

            case OCTOBER:

                return 274 + leap;

            case NOVEMBER:

                return 305 + leap;

            case DECEMBER:

            default:

                return 335 + leap;

        }