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	/*
	* Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
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	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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) 2012-2013, Stephen Colebourne & Michael Nascimento Santos
	*
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* * Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	*
	* * Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	*
	* * Neither the name of JSR-310 nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	package java.time.temporal;

	import static java.time.temporal.ChronoField.DAY_OF_MONTH;
	import static java.time.temporal.ChronoField.DAY_OF_WEEK;
	import static java.time.temporal.ChronoField.DAY_OF_YEAR;
	import static java.time.temporal.ChronoUnit.DAYS;
	import static java.time.temporal.ChronoUnit.MONTHS;
	import static java.time.temporal.ChronoUnit.YEARS;

	import java.time.DayOfWeek;
	import java.time.LocalDate;
	import java.util.Objects;
	import java.util.function.UnaryOperator;

	/**
	* Common and useful TemporalAdjusters.
	* <p>
	* Adjusters are a key tool for modifying temporal objects.
	* They exist to externalize the process of adjustment, permitting different
	* approaches, as per the strategy design pattern.
	* Examples might be an adjuster that sets the date avoiding weekends, or one that
	* sets the date to the last day of the month.
	* <p>
	* There are two equivalent ways of using a {@code TemporalAdjuster}.
	* The first is to invoke the method on the interface directly.
	* The second is to use {@link Temporal#with(TemporalAdjuster)}:
	* <pre>
	* // these two lines are equivalent, but the second approach is recommended
	* temporal = thisAdjuster.adjustInto(temporal);
	* temporal = temporal.with(thisAdjuster);
	* </pre>
	* It is recommended to use the second approach, {@code with(TemporalAdjuster)},
	* as it is a lot clearer to read in code.
	* <p>
	* This class contains a standard set of adjusters, available as static methods.
	* These include:
	* <ul>
	* <li>finding the first or last day of the month
	* <li>finding the first day of next month
	* <li>finding the first or last day of the year
	* <li>finding the first day of next year
	* <li>finding the first or last day-of-week within a month, such as "first Wednesday in June"
	* <li>finding the next or previous day-of-week, such as "next Thursday"
	* </ul>
	*
	* @implSpec
	* All the implementations supplied by the static methods are immutable.
	*
	* @see TemporalAdjuster
	* @since 1.8
	*/
	public final class TemporalAdjusters {

	/**
	* Private constructor since this is a utility class.
	*/
	private TemporalAdjusters() {
	}

	//-----------------------------------------------------------------------
	/**
	* Obtains a {@code TemporalAdjuster} that wraps a date adjuster.
	* <p>
	* The {@code TemporalAdjuster} is based on the low level {@code Temporal} interface.
	* This method allows an adjustment from {@code LocalDate} to {@code LocalDate}
	* to be wrapped to match the temporal-based interface.
	* This is provided for convenience to make user-written adjusters simpler.
	* <p>
	* In general, user-written adjusters should be static constants:
	* <pre>{@code
	* static TemporalAdjuster TWO_DAYS_LATER =
	* TemporalAdjusters.ofDateAdjuster(date -> date.plusDays(2));
	* }</pre>
	*
	* @param dateBasedAdjuster the date-based adjuster, not null
	* @return the temporal adjuster wrapping on the date adjuster, not null
	*/
	public static TemporalAdjuster ofDateAdjuster(UnaryOperator<LocalDate> dateBasedAdjuster) {
	Objects.requireNonNull(dateBasedAdjuster, "dateBasedAdjuster");
	return (temporal) -> {
	LocalDate input = LocalDate.from(temporal);
	LocalDate output = dateBasedAdjuster.apply(input);
	return temporal.with(output);
	};
	}

	//-----------------------------------------------------------------------
	/**
	* Returns the "first day of month" adjuster, which returns a new date set to
	* the first day of the current month.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2011-01-01.<br>
	* The input 2011-02-15 will return 2011-02-01.
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* temporal.with(DAY_OF_MONTH, 1);
	* </pre>
	*
	* @return the first day-of-month adjuster, not null
	*/
	public static TemporalAdjuster firstDayOfMonth() {
	return (temporal) -> temporal.with(DAY_OF_MONTH, 1);
	}

	/**
	* Returns the "last day of month" adjuster, which returns a new date set to
	* the last day of the current month.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2011-01-31.<br>
	* The input 2011-02-15 will return 2011-02-28.<br>
	* The input 2012-02-15 will return 2012-02-29 (leap year).<br>
	* The input 2011-04-15 will return 2011-04-30.
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* long lastDay = temporal.range(DAY_OF_MONTH).getMaximum();
	* temporal.with(DAY_OF_MONTH, lastDay);
	* </pre>
	*
	* @return the last day-of-month adjuster, not null
	*/
	public static TemporalAdjuster lastDayOfMonth() {
	return (temporal) -> temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum());
	}

	/**
	* Returns the "first day of next month" adjuster, which returns a new date set to
	* the first day of the next month.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2011-02-01.<br>
	* The input 2011-02-15 will return 2011-03-01.
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS);
	* </pre>
	*
	* @return the first day of next month adjuster, not null
	*/
	public static TemporalAdjuster firstDayOfNextMonth() {
	return (temporal) -> temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS);
	}

	//-----------------------------------------------------------------------
	/**
	* Returns the "first day of year" adjuster, which returns a new date set to
	* the first day of the current year.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2011-01-01.<br>
	* The input 2011-02-15 will return 2011-01-01.<br>
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* temporal.with(DAY_OF_YEAR, 1);
	* </pre>
	*
	* @return the first day-of-year adjuster, not null
	*/
	public static TemporalAdjuster firstDayOfYear() {
	return (temporal) -> temporal.with(DAY_OF_YEAR, 1);
	}

	/**
	* Returns the "last day of year" adjuster, which returns a new date set to
	* the last day of the current year.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2011-12-31.<br>
	* The input 2011-02-15 will return 2011-12-31.<br>
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* long lastDay = temporal.range(DAY_OF_YEAR).getMaximum();
	* temporal.with(DAY_OF_YEAR, lastDay);
	* </pre>
	*
	* @return the last day-of-year adjuster, not null
	*/
	public static TemporalAdjuster lastDayOfYear() {
	return (temporal) -> temporal.with(DAY_OF_YEAR, temporal.range(DAY_OF_YEAR).getMaximum());
	}

	/**
	* Returns the "first day of next year" adjuster, which returns a new date set to
	* the first day of the next year.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 will return 2012-01-01.
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It is equivalent to:
	* <pre>
	* temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS);
	* </pre>
	*
	* @return the first day of next month adjuster, not null
	*/
	public static TemporalAdjuster firstDayOfNextYear() {
	return (temporal) -> temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS);
	}

	//-----------------------------------------------------------------------
	/**
	* Returns the first in month adjuster, which returns a new date
	* in the same month with the first matching day-of-week.
	* This is used for expressions like 'first Tuesday in March'.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-12-15 for (MONDAY) will return 2011-12-05.<br>
	* The input 2011-12-15 for (FRIDAY) will return 2011-12-02.<br>
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
	* and the {@code DAYS} unit, and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week, not null
	* @return the first in month adjuster, not null
	*/
	public static TemporalAdjuster firstInMonth(DayOfWeek dayOfWeek) {
	return TemporalAdjusters.dayOfWeekInMonth(1, dayOfWeek);
	}

	/**
	* Returns the last in month adjuster, which returns a new date
	* in the same month with the last matching day-of-week.
	* This is used for expressions like 'last Tuesday in March'.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-12-15 for (MONDAY) will return 2011-12-26.<br>
	* The input 2011-12-15 for (FRIDAY) will return 2011-12-30.<br>
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
	* and the {@code DAYS} unit, and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week, not null
	* @return the first in month adjuster, not null
	*/
	public static TemporalAdjuster lastInMonth(DayOfWeek dayOfWeek) {
	return TemporalAdjusters.dayOfWeekInMonth(-1, dayOfWeek);
	}

	/**
	* Returns the day-of-week in month adjuster, which returns a new date
	* with the ordinal day-of-week based on the month.
	* This is used for expressions like the 'second Tuesday in March'.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-12-15 for (1,TUESDAY) will return 2011-12-06.<br>
	* The input 2011-12-15 for (2,TUESDAY) will return 2011-12-13.<br>
	* The input 2011-12-15 for (3,TUESDAY) will return 2011-12-20.<br>
	* The input 2011-12-15 for (4,TUESDAY) will return 2011-12-27.<br>
	* The input 2011-12-15 for (5,TUESDAY) will return 2012-01-03.<br>
	* The input 2011-12-15 for (-1,TUESDAY) will return 2011-12-27 (last in month).<br>
	* The input 2011-12-15 for (-4,TUESDAY) will return 2011-12-06 (3 weeks before last in month).<br>
	* The input 2011-12-15 for (-5,TUESDAY) will return 2011-11-29 (4 weeks before last in month).<br>
	* The input 2011-12-15 for (0,TUESDAY) will return 2011-11-29 (last in previous month).<br>
	* <p>
	* For a positive or zero ordinal, the algorithm is equivalent to finding the first
	* day-of-week that matches within the month and then adding a number of weeks to it.
	* For a negative ordinal, the algorithm is equivalent to finding the last
	* day-of-week that matches within the month and then subtracting a number of weeks to it.
	* The ordinal number of weeks is not validated and is interpreted leniently
	* according to this algorithm. This definition means that an ordinal of zero finds
	* the last matching day-of-week in the previous month.
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
	* and the {@code DAYS} unit, and assumes a seven day week.
	*
	* @param ordinal the week within the month, unbounded but typically from -5 to 5
	* @param dayOfWeek the day-of-week, not null
	* @return the day-of-week in month adjuster, not null
	*/
	public static TemporalAdjuster dayOfWeekInMonth(int ordinal, DayOfWeek dayOfWeek) {
	Objects.requireNonNull(dayOfWeek, "dayOfWeek");
	int dowValue = dayOfWeek.getValue();
	if (ordinal >= 0) {
	return (temporal) -> {
	Temporal temp = temporal.with(DAY_OF_MONTH, 1);
	int curDow = temp.get(DAY_OF_WEEK);
	int dowDiff = (dowValue - curDow + 7) % 7;
	dowDiff += (ordinal - 1L) * 7L; // safe from overflow
	return temp.plus(dowDiff, DAYS);
	};
	} else {
	return (temporal) -> {
	Temporal temp = temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum());
	int curDow = temp.get(DAY_OF_WEEK);
	int daysDiff = dowValue - curDow;
	daysDiff = (daysDiff == 0 ? 0 : (daysDiff > 0 ? daysDiff - 7 : daysDiff));
	daysDiff -= (-ordinal - 1L) * 7L; // safe from overflow
	return temp.plus(daysDiff, DAYS);
	};
	}
	}

	//-----------------------------------------------------------------------
	/**
	* Returns the next day-of-week adjuster, which adjusts the date to the
	* first occurrence of the specified day-of-week after the date being adjusted.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br>
	* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br>
	* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-22 (seven days later).
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
	* and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week to move the date to, not null
	* @return the next day-of-week adjuster, not null
	*/
	public static TemporalAdjuster next(DayOfWeek dayOfWeek) {
	int dowValue = dayOfWeek.getValue();
	return (temporal) -> {
	int calDow = temporal.get(DAY_OF_WEEK);
	int daysDiff = calDow - dowValue;
	return temporal.plus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
	};
	}

	/**
	* Returns the next-or-same day-of-week adjuster, which adjusts the date to the
	* first occurrence of the specified day-of-week after the date being adjusted
	* unless it is already on that day in which case the same object is returned.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br>
	* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br>
	* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input).
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
	* and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week to check for or move the date to, not null
	* @return the next-or-same day-of-week adjuster, not null
	*/
	public static TemporalAdjuster nextOrSame(DayOfWeek dayOfWeek) {
	int dowValue = dayOfWeek.getValue();
	return (temporal) -> {
	int calDow = temporal.get(DAY_OF_WEEK);
	if (calDow == dowValue) {
	return temporal;
	}
	int daysDiff = calDow - dowValue;
	return temporal.plus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
	};
	}

	/**
	* Returns the previous day-of-week adjuster, which adjusts the date to the
	* first occurrence of the specified day-of-week before the date being adjusted.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br>
	* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br>
	* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-08 (seven days earlier).
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
	* and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week to move the date to, not null
	* @return the previous day-of-week adjuster, not null
	*/
	public static TemporalAdjuster previous(DayOfWeek dayOfWeek) {
	int dowValue = dayOfWeek.getValue();
	return (temporal) -> {
	int calDow = temporal.get(DAY_OF_WEEK);
	int daysDiff = dowValue - calDow;
	return temporal.minus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
	};
	}

	/**
	* Returns the previous-or-same day-of-week adjuster, which adjusts the date to the
	* first occurrence of the specified day-of-week before the date being adjusted
	* unless it is already on that day in which case the same object is returned.
	* <p>
	* The ISO calendar system behaves as follows:<br>
	* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br>
	* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br>
	* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input).
	* <p>
	* The behavior is suitable for use with most calendar systems.
	* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
	* and assumes a seven day week.
	*
	* @param dayOfWeek the day-of-week to check for or move the date to, not null
	* @return the previous-or-same day-of-week adjuster, not null
	*/
	public static TemporalAdjuster previousOrSame(DayOfWeek dayOfWeek) {
	int dowValue = dayOfWeek.getValue();
	return (temporal) -> {
	int calDow = temporal.get(DAY_OF_WEEK);
	if (calDow == dowValue) {
	return temporal;
	}
	int daysDiff = dowValue - calDow;
	return temporal.minus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
	};
	}

	}

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