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	/*
	* Copyright (c) 2012, 2013, 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
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* 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) 2011-2012, 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.
	*
	* * 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
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	package java.time.format;

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

	import java.time.DateTimeException;
	import java.time.Instant;
	import java.time.ZoneId;
	import java.time.ZoneOffset;
	import java.time.chrono.ChronoLocalDate;
	import java.time.chrono.Chronology;
	import java.time.chrono.IsoChronology;
	import java.time.temporal.ChronoField;
	import java.time.temporal.TemporalAccessor;
	import java.time.temporal.TemporalField;
	import java.time.temporal.TemporalQueries;
	import java.time.temporal.TemporalQuery;
	import java.time.temporal.ValueRange;
	import java.util.Locale;
	import java.util.Objects;

	/**
	* Context object used during date and time printing.
	* <p>
	* This class provides a single wrapper to items used in the format.
	*
	* @implSpec
	* This class is a mutable context intended for use from a single thread.
	* Usage of the class is thread-safe within standard printing as the framework creates
	* a new instance of the class for each format and printing is single-threaded.
	*
	* @since 1.8
	*/
	final class DateTimePrintContext {

	/**
	* The temporal being output.
	*/
	private TemporalAccessor temporal;
	/**
	* The formatter, not null.
	*/
	private DateTimeFormatter formatter;
	/**
	* Whether the current formatter is optional.
	*/
	private int optional;

	/**
	* Creates a new instance of the context.
	*
	* @param temporal the temporal object being output, not null
	* @param formatter the formatter controlling the format, not null
	*/
	DateTimePrintContext(TemporalAccessor temporal, DateTimeFormatter formatter) {
	super();
	this.temporal = adjust(temporal, formatter);
	this.formatter = formatter;
	}

	private static TemporalAccessor adjust(final TemporalAccessor temporal, DateTimeFormatter formatter) {
	// normal case first (early return is an optimization)
	Chronology overrideChrono = formatter.getChronology();
	ZoneId overrideZone = formatter.getZone();
	if (overrideChrono == null && overrideZone == null) {
	return temporal;
	}

	// ensure minimal change (early return is an optimization)
	Chronology temporalChrono = temporal.query(TemporalQueries.chronology());
	ZoneId temporalZone = temporal.query(TemporalQueries.zoneId());
	if (Objects.equals(overrideChrono, temporalChrono)) {
	overrideChrono = null;
	}
	if (Objects.equals(overrideZone, temporalZone)) {
	overrideZone = null;
	}
	if (overrideChrono == null && overrideZone == null) {
	return temporal;
	}

	// make adjustment
	final Chronology effectiveChrono = (overrideChrono != null ? overrideChrono : temporalChrono);
	if (overrideZone != null) {
	// if have zone and instant, calculation is simple, defaulting chrono if necessary
	if (temporal.isSupported(INSTANT_SECONDS)) {
	Chronology chrono = (effectiveChrono != null ? effectiveChrono : IsoChronology.INSTANCE);
	return chrono.zonedDateTime(Instant.from(temporal), overrideZone);
	}
	// block changing zone on OffsetTime, and similar problem cases
	if (overrideZone.normalized() instanceof ZoneOffset && temporal.isSupported(OFFSET_SECONDS) &&
	temporal.get(OFFSET_SECONDS) != overrideZone.getRules().getOffset(Instant.EPOCH).getTotalSeconds()) {
	throw new DateTimeException("Unable to apply override zone '" + overrideZone +
	"' because the temporal object being formatted has a different offset but" +
	" does not represent an instant: " + temporal);
	}
	}
	final ZoneId effectiveZone = (overrideZone != null ? overrideZone : temporalZone);
	final ChronoLocalDate effectiveDate;
	if (overrideChrono != null) {
	if (temporal.isSupported(EPOCH_DAY)) {
	effectiveDate = effectiveChrono.date(temporal);
	} else {
	// check for date fields other than epoch-day, ignoring case of converting null to ISO
	if (!(overrideChrono == IsoChronology.INSTANCE && temporalChrono == null)) {
	for (ChronoField f : ChronoField.values()) {
	if (f.isDateBased() && temporal.isSupported(f)) {
	throw new DateTimeException("Unable to apply override chronology '" + overrideChrono +
	"' because the temporal object being formatted contains date fields but" +
	" does not represent a whole date: " + temporal);
	}
	}
	}
	effectiveDate = null;
	}
	} else {
	effectiveDate = null;
	}

	// combine available data
	// this is a non-standard temporal that is almost a pure delegate
	// this better handles map-like underlying temporal instances
	return new TemporalAccessor() {
	@Override
	public boolean isSupported(TemporalField field) {
	if (effectiveDate != null && field.isDateBased()) {
	return effectiveDate.isSupported(field);
	}
	return temporal.isSupported(field);
	}
	@Override
	public ValueRange range(TemporalField field) {
	if (effectiveDate != null && field.isDateBased()) {
	return effectiveDate.range(field);
	}
	return temporal.range(field);
	}
	@Override
	public long getLong(TemporalField field) {
	if (effectiveDate != null && field.isDateBased()) {
	return effectiveDate.getLong(field);
	}
	return temporal.getLong(field);
	}
	@SuppressWarnings("unchecked")
	@Override
	public <R> R query(TemporalQuery<R> query) {
	if (query == TemporalQueries.chronology()) {
	return (R) effectiveChrono;
	}
	if (query == TemporalQueries.zoneId()) {
	return (R) effectiveZone;
	}
	if (query == TemporalQueries.precision()) {
	return temporal.query(query);
	}
	return query.queryFrom(this);
	}
	};
	}

	//-----------------------------------------------------------------------
	/**
	* Gets the temporal object being output.
	*
	* @return the temporal object, not null
	*/
	TemporalAccessor getTemporal() {
	return temporal;
	}

	/**
	* Gets the locale.
	* <p>
	* This locale is used to control localization in the format output except
	* where localization is controlled by the DecimalStyle.
	*
	* @return the locale, not null
	*/
	Locale getLocale() {
	return formatter.getLocale();
	}

	/**
	* Gets the DecimalStyle.
	* <p>
	* The DecimalStyle controls the localization of numeric output.
	*
	* @return the DecimalStyle, not null
	*/
	DecimalStyle getDecimalStyle() {
	return formatter.getDecimalStyle();
	}

	//-----------------------------------------------------------------------
	/**
	* Starts the printing of an optional segment of the input.
	*/
	void startOptional() {
	this.optional++;
	}

	/**
	* Ends the printing of an optional segment of the input.
	*/
	void endOptional() {
	this.optional--;
	}

	/**
	* Gets a value using a query.
	*
	* @param query the query to use, not null
	* @return the result, null if not found and optional is true
	* @throws DateTimeException if the type is not available and the section is not optional
	*/
	<R> R getValue(TemporalQuery<R> query) {
	R result = temporal.query(query);
	if (result == null && optional == 0) {
	throw new DateTimeException("Unable to extract value: " + temporal.getClass());
	}
	return result;
	}

	/**
	* Gets the value of the specified field.
	* <p>
	* This will return the value for the specified field.
	*
	* @param field the field to find, not null
	* @return the value, null if not found and optional is true
	* @throws DateTimeException if the field is not available and the section is not optional
	*/
	Long getValue(TemporalField field) {
	try {
	return temporal.getLong(field);
	} catch (DateTimeException ex) {
	if (optional > 0) {
	return null;
	}
	throw ex;
	}
	}

	//-----------------------------------------------------------------------
	/**
	* Returns a string version of the context for debugging.
	*
	* @return a string representation of the context, not null
	*/
	@Override
	public String toString() {
	return temporal.toString();
	}

	}

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