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	/*
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	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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	* published by the Free Software Foundation. Oracle designates this
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	*
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	* version 2 for more details (a copy is included in the LICENSE file that
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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.
	*
	* 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.
	*
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	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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	package java.time.temporal;

	import static java.time.temporal.ChronoField.EPOCH_DAY;
	import static java.time.temporal.ChronoField.NANO_OF_DAY;
	import static java.time.temporal.ChronoField.OFFSET_SECONDS;

	import java.time.LocalDate;
	import java.time.LocalTime;
	import java.time.ZoneId;
	import java.time.ZoneOffset;
	import java.time.chrono.Chronology;

	/**
	* Common implementations of {@code TemporalQuery}.
	* <p>
	* This class provides common implementations of {@link TemporalQuery}.
	* These are defined here as they must be constants, and the definition
	* of lambdas does not guarantee that. By assigning them once here,
	* they become 'normal' Java constants.
	* <p>
	* Queries are a key tool for extracting information from temporal objects.
	* They exist to externalize the process of querying, permitting different
	* approaches, as per the strategy design pattern.
	* Examples might be a query that checks if the date is the day before February 29th
	* in a leap year, or calculates the number of days to your next birthday.
	* <p>
	* The {@link TemporalField} interface provides another mechanism for querying
	* temporal objects. That interface is limited to returning a {@code long}.
	* By contrast, queries can return any type.
	* <p>
	* There are two equivalent ways of using a {@code TemporalQuery}.
	* The first is to invoke the method on this interface directly.
	* The second is to use {@link TemporalAccessor#query(TemporalQuery)}:
	* <pre>
	* // these two lines are equivalent, but the second approach is recommended
	* temporal = thisQuery.queryFrom(temporal);
	* temporal = temporal.query(thisQuery);
	* </pre>
	* It is recommended to use the second approach, {@code query(TemporalQuery)},
	* as it is a lot clearer to read in code.
	* <p>
	* The most common implementations are method references, such as
	* {@code LocalDate::from} and {@code ZoneId::from}.
	* Additional common queries are provided to return:
	* <ul>
	* <li> a Chronology,
	* <li> a LocalDate,
	* <li> a LocalTime,
	* <li> a ZoneOffset,
	* <li> a precision,
	* <li> a zone, or
	* <li> a zoneId.
	* </ul>
	*
	* @since 1.8
	*/
	public final class TemporalQueries {
	// note that it is vital that each method supplies a constant, not a
	// calculated value, as they will be checked for using ==
	// it is also vital that each constant is different (due to the == checking)
	// as such, alterations to this code must be done with care

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

	//-----------------------------------------------------------------------
	// special constants should be used to extract information from a TemporalAccessor
	// that cannot be derived in other ways
	// Javadoc added here, so as to pretend they are more normal than they really are

	/**
	* A strict query for the {@code ZoneId}.
	* <p>
	* This queries a {@code TemporalAccessor} for the zone.
	* The zone is only returned if the date-time conceptually contains a {@code ZoneId}.
	* It will not be returned if the date-time only conceptually has an {@code ZoneOffset}.
	* Thus a {@link java.time.ZonedDateTime} will return the result of {@code getZone()},
	* but an {@link java.time.OffsetDateTime} will return null.
	* <p>
	* In most cases, applications should use {@link #zone()} as this query is too strict.
	* <p>
	* The result from JDK classes implementing {@code TemporalAccessor} is as follows:<br>
	* {@code LocalDate} returns null<br>
	* {@code LocalTime} returns null<br>
	* {@code LocalDateTime} returns null<br>
	* {@code ZonedDateTime} returns the associated zone<br>
	* {@code OffsetTime} returns null<br>
	* {@code OffsetDateTime} returns null<br>
	* {@code ChronoLocalDate} returns null<br>
	* {@code ChronoLocalDateTime} returns null<br>
	* {@code ChronoZonedDateTime} returns the associated zone<br>
	* {@code Era} returns null<br>
	* {@code DayOfWeek} returns null<br>
	* {@code Month} returns null<br>
	* {@code Year} returns null<br>
	* {@code YearMonth} returns null<br>
	* {@code MonthDay} returns null<br>
	* {@code ZoneOffset} returns null<br>
	* {@code Instant} returns null<br>
	*
	* @return a query that can obtain the zone ID of a temporal, not null
	*/
	public static TemporalQuery<ZoneId> zoneId() {
	return TemporalQueries.ZONE_ID;
	}

	/**
	* A query for the {@code Chronology}.
	* <p>
	* This queries a {@code TemporalAccessor} for the chronology.
	* If the target {@code TemporalAccessor} represents a date, or part of a date,
	* then it should return the chronology that the date is expressed in.
	* As a result of this definition, objects only representing time, such as
	* {@code LocalTime}, will return null.
	* <p>
	* The result from JDK classes implementing {@code TemporalAccessor} is as follows:<br>
	* {@code LocalDate} returns {@code IsoChronology.INSTANCE}<br>
	* {@code LocalTime} returns null (does not represent a date)<br>
	* {@code LocalDateTime} returns {@code IsoChronology.INSTANCE}<br>
	* {@code ZonedDateTime} returns {@code IsoChronology.INSTANCE}<br>
	* {@code OffsetTime} returns null (does not represent a date)<br>
	* {@code OffsetDateTime} returns {@code IsoChronology.INSTANCE}<br>
	* {@code ChronoLocalDate} returns the associated chronology<br>
	* {@code ChronoLocalDateTime} returns the associated chronology<br>
	* {@code ChronoZonedDateTime} returns the associated chronology<br>
	* {@code Era} returns the associated chronology<br>
	* {@code DayOfWeek} returns null (shared across chronologies)<br>
	* {@code Month} returns {@code IsoChronology.INSTANCE}<br>
	* {@code Year} returns {@code IsoChronology.INSTANCE}<br>
	* {@code YearMonth} returns {@code IsoChronology.INSTANCE}<br>
	* {@code MonthDay} returns null {@code IsoChronology.INSTANCE}<br>
	* {@code ZoneOffset} returns null (does not represent a date)<br>
	* {@code Instant} returns null (does not represent a date)<br>
	* <p>
	* The method {@link java.time.chrono.Chronology#from(TemporalAccessor)} can be used as a
	* {@code TemporalQuery} via a method reference, {@code Chronology::from}.
	* That method is equivalent to this query, except that it throws an
	* exception if a chronology cannot be obtained.
	*
	* @return a query that can obtain the chronology of a temporal, not null
	*/
	public static TemporalQuery<Chronology> chronology() {
	return TemporalQueries.CHRONO;
	}

	/**
	* A query for the smallest supported unit.
	* <p>
	* This queries a {@code TemporalAccessor} for the time precision.
	* If the target {@code TemporalAccessor} represents a consistent or complete date-time,
	* date or time then this must return the smallest precision actually supported.
	* Note that fields such as {@code NANO_OF_DAY} and {@code NANO_OF_SECOND}
	* are defined to always return ignoring the precision, thus this is the only
	* way to find the actual smallest supported unit.
	* For example, were {@code GregorianCalendar} to implement {@code TemporalAccessor}
	* it would return a precision of {@code MILLIS}.
	* <p>
	* The result from JDK classes implementing {@code TemporalAccessor} is as follows:<br>
	* {@code LocalDate} returns {@code DAYS}<br>
	* {@code LocalTime} returns {@code NANOS}<br>
	* {@code LocalDateTime} returns {@code NANOS}<br>
	* {@code ZonedDateTime} returns {@code NANOS}<br>
	* {@code OffsetTime} returns {@code NANOS}<br>
	* {@code OffsetDateTime} returns {@code NANOS}<br>
	* {@code ChronoLocalDate} returns {@code DAYS}<br>
	* {@code ChronoLocalDateTime} returns {@code NANOS}<br>
	* {@code ChronoZonedDateTime} returns {@code NANOS}<br>
	* {@code Era} returns {@code ERAS}<br>
	* {@code DayOfWeek} returns {@code DAYS}<br>
	* {@code Month} returns {@code MONTHS}<br>
	* {@code Year} returns {@code YEARS}<br>
	* {@code YearMonth} returns {@code MONTHS}<br>
	* {@code MonthDay} returns null (does not represent a complete date or time)<br>
	* {@code ZoneOffset} returns null (does not represent a date or time)<br>
	* {@code Instant} returns {@code NANOS}<br>
	*
	* @return a query that can obtain the precision of a temporal, not null
	*/
	public static TemporalQuery<TemporalUnit> precision() {
	return TemporalQueries.PRECISION;
	}

	//-----------------------------------------------------------------------
	// non-special constants are standard queries that derive information from other information
	/**
	* A lenient query for the {@code ZoneId}, falling back to the {@code ZoneOffset}.
	* <p>
	* This queries a {@code TemporalAccessor} for the zone.
	* It first tries to obtain the zone, using {@link #zoneId()}.
	* If that is not found it tries to obtain the {@link #offset()}.
	* Thus a {@link java.time.ZonedDateTime} will return the result of {@code getZone()},
	* while an {@link java.time.OffsetDateTime} will return the result of {@code getOffset()}.
	* <p>
	* In most cases, applications should use this query rather than {@code #zoneId()}.
	* <p>
	* The method {@link ZoneId#from(TemporalAccessor)} can be used as a
	* {@code TemporalQuery} via a method reference, {@code ZoneId::from}.
	* That method is equivalent to this query, except that it throws an
	* exception if a zone cannot be obtained.
	*
	* @return a query that can obtain the zone ID or offset of a temporal, not null
	*/
	public static TemporalQuery<ZoneId> zone() {
	return TemporalQueries.ZONE;
	}

	/**
	* A query for {@code ZoneOffset} returning null if not found.
	* <p>
	* This returns a {@code TemporalQuery} that can be used to query a temporal
	* object for the offset. The query will return null if the temporal
	* object cannot supply an offset.
	* <p>
	* The query implementation examines the {@link ChronoField#OFFSET_SECONDS OFFSET_SECONDS}
	* field and uses it to create a {@code ZoneOffset}.
	* <p>
	* The method {@link java.time.ZoneOffset#from(TemporalAccessor)} can be used as a
	* {@code TemporalQuery} via a method reference, {@code ZoneOffset::from}.
	* This query and {@code ZoneOffset::from} will return the same result if the
	* temporal object contains an offset. If the temporal object does not contain
	* an offset, then the method reference will throw an exception, whereas this
	* query will return null.
	*
	* @return a query that can obtain the offset of a temporal, not null
	*/
	public static TemporalQuery<ZoneOffset> offset() {
	return TemporalQueries.OFFSET;
	}

	/**
	* A query for {@code LocalDate} returning null if not found.
	* <p>
	* This returns a {@code TemporalQuery} that can be used to query a temporal
	* object for the local date. The query will return null if the temporal
	* object cannot supply a local date.
	* <p>
	* The query implementation examines the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
	* field and uses it to create a {@code LocalDate}.
	* <p>
	* The method {@link ZoneOffset#from(TemporalAccessor)} can be used as a
	* {@code TemporalQuery} via a method reference, {@code LocalDate::from}.
	* This query and {@code LocalDate::from} will return the same result if the
	* temporal object contains a date. If the temporal object does not contain
	* a date, then the method reference will throw an exception, whereas this
	* query will return null.
	*
	* @return a query that can obtain the date of a temporal, not null
	*/
	public static TemporalQuery<LocalDate> localDate() {
	return TemporalQueries.LOCAL_DATE;
	}

	/**
	* A query for {@code LocalTime} returning null if not found.
	* <p>
	* This returns a {@code TemporalQuery} that can be used to query a temporal
	* object for the local time. The query will return null if the temporal
	* object cannot supply a local time.
	* <p>
	* The query implementation examines the {@link ChronoField#NANO_OF_DAY NANO_OF_DAY}
	* field and uses it to create a {@code LocalTime}.
	* <p>
	* The method {@link ZoneOffset#from(TemporalAccessor)} can be used as a
	* {@code TemporalQuery} via a method reference, {@code LocalTime::from}.
	* This query and {@code LocalTime::from} will return the same result if the
	* temporal object contains a time. If the temporal object does not contain
	* a time, then the method reference will throw an exception, whereas this
	* query will return null.
	*
	* @return a query that can obtain the time of a temporal, not null
	*/
	public static TemporalQuery<LocalTime> localTime() {
	return TemporalQueries.LOCAL_TIME;
	}

	//-----------------------------------------------------------------------
	/**
	* A strict query for the {@code ZoneId}.
	*/
	static final TemporalQuery<ZoneId> ZONE_ID = new TemporalQuery<>() {
	@Override
	public ZoneId queryFrom(TemporalAccessor temporal) {
	return temporal.query(TemporalQueries.ZONE_ID);
	}

	@Override
	public String toString() {
	return "ZoneId";
	}
	};

	/**
	* A query for the {@code Chronology}.
	*/
	static final TemporalQuery<Chronology> CHRONO = new TemporalQuery<>() {
	@Override
	public Chronology queryFrom(TemporalAccessor temporal) {
	return temporal.query(TemporalQueries.CHRONO);
	}

	@Override
	public String toString() {
	return "Chronology";
	}
	};


	/**
	* A query for the smallest supported unit.
	*/
	static final TemporalQuery<TemporalUnit> PRECISION = new TemporalQuery<>() {
	@Override
	public TemporalUnit queryFrom(TemporalAccessor temporal) {
	return temporal.query(TemporalQueries.PRECISION);
	}

	@Override
	public String toString() {
	return "Precision";
	}
	};

	//-----------------------------------------------------------------------
	/**
	* A query for {@code ZoneOffset} returning null if not found.
	*/
	static final TemporalQuery<ZoneOffset> OFFSET = new TemporalQuery<>() {
	@Override
	public ZoneOffset queryFrom(TemporalAccessor temporal) {
	if (temporal.isSupported(OFFSET_SECONDS)) {
	return ZoneOffset.ofTotalSeconds(temporal.get(OFFSET_SECONDS));
	}
	return null;
	}

	@Override
	public String toString() {
	return "ZoneOffset";
	}
	};

	/**
	* A lenient query for the {@code ZoneId}, falling back to the {@code ZoneOffset}.
	*/
	static final TemporalQuery<ZoneId> ZONE = new TemporalQuery<>() {
	@Override
	public ZoneId queryFrom(TemporalAccessor temporal) {
	ZoneId zone = temporal.query(ZONE_ID);
	return (zone != null ? zone : temporal.query(OFFSET));
	}

	@Override
	public String toString() {
	return "Zone";
	}
	};

	/**
	* A query for {@code LocalDate} returning null if not found.
	*/
	static final TemporalQuery<LocalDate> LOCAL_DATE = new TemporalQuery<>() {
	@Override
	public LocalDate queryFrom(TemporalAccessor temporal) {
	if (temporal.isSupported(EPOCH_DAY)) {
	return LocalDate.ofEpochDay(temporal.getLong(EPOCH_DAY));
	}
	return null;
	}

	@Override
	public String toString() {
	return "LocalDate";
	}
	};

	/**
	* A query for {@code LocalTime} returning null if not found.
	*/
	static final TemporalQuery<LocalTime> LOCAL_TIME = new TemporalQuery<>() {
	@Override
	public LocalTime queryFrom(TemporalAccessor temporal) {
	if (temporal.isSupported(NANO_OF_DAY)) {
	return LocalTime.ofNanoOfDay(temporal.getLong(NANO_OF_DAY));
	}
	return null;
	}

	@Override
	public String toString() {
	return "LocalTime";
	}
	};

	}

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