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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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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.

 *

 *  * 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.

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 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

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 *

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package java.time;

import java.io.DataOutput;

import java.io.IOException;

import java.io.Serializable;

import java.time.format.DateTimeFormatterBuilder;

import java.time.format.TextStyle;

import java.time.temporal.Queries;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.TemporalField;

import java.time.temporal.TemporalQuery;

import java.time.zone.ZoneRules;

import java.time.zone.ZoneRulesProvider;

import java.util.Collections;

import java.util.HashMap;

import java.util.Locale;

import java.util.Map;

import java.util.Objects;

import java.util.TimeZone;

/**

 * A time-zone ID, such as {@code Europe/Paris}.

 * <p>

 * A {@code ZoneId} is used to identify the rules used to convert between

 * an {@link Instant} and a {@link LocalDateTime}.

 * There are two distinct types of ID:

 * <p><ul>

 * <li>Fixed offsets - a fully resolved offset from UTC/Greenwich, that uses

 *  the same offset for all local date-times

 * <li>Geographical regions - an area where a specific set of rules for finding

 *  the offset from UTC/Greenwich apply

 * </ul><p>

 * Most fixed offsets are represented by {@link ZoneOffset}.

 * <p>

 * The actual rules, describing when and how the offset changes, are defined by {@link ZoneRules}.

 * This class is simply an ID used to obtain the underlying rules.

 * This approach is taken because rules are defined by governments and change

 * frequently, whereas the ID is stable.

 * <p>

 * The distinction has other effects. Serializing the {@code ZoneId} will only send

 * the ID, whereas serializing the rules sends the entire data set.

 * Similarly, a comparison of two IDs only examines the ID, whereas

 * a comparison of two rules examines the entire data set.

 * <p>

 * The code supports loading a {@code ZoneId} on a JVM which does not have available rules

 * for that ID. This allows the date-time object, such as {@link ZonedDateTime},

 * to still be queried.

 *

 * <h3>Time-zone IDs</h3>

 * The ID is unique within the system.

 * The formats for offset and region IDs differ.

 * <p>

 * An ID is parsed as an offset ID if it starts with 'UTC', 'GMT', '+' or '-', or

 * is a single letter.

 * For example, 'Z', '+02:00', '-05:00', 'UTC+05' and 'GMT-6' are all valid offset IDs.

 * Note that some IDs, such as 'D' or '+ABC' meet the criteria, but are invalid.

 * <p>

 * All other IDs are considered to be region IDs.

 * <p>

 * Region IDs are defined by configuration, which can be thought of as a {@code Map}

 * from region ID to {@code ZoneRules}, see {@link ZoneRulesProvider}.

 * <p>

 * Time-zones are defined by governments and change frequently. There are a number of

 * organizations, known here as groups, that monitor time-zone changes and collate them.

 * The default group is the IANA Time Zone Database (TZDB).

 * Other organizations include IATA (the airline industry body) and Microsoft.

 * <p>

 * Each group defines its own format for region ID.

 * The TZDB group defines IDs such as 'Europe/London' or 'America/New_York'.

 * TZDB IDs take precedence over other groups.

 * <p>

 * It is strongly recommended that the group name is included in all Ids supplied by

 * groups other than TZDB to avoid conflicts. For example, IATA airline time-zone

 * region IDs are typically the same as the three letter airport code.

 * However, the airport of Utrecht has the code 'UTC', which is obviously a conflict.

 * The recommended format for region IDs from groups other than TZDB is 'group~region'.

 * Thus if IATA data were defined, Utrecht airport would be 'IATA~UTC'.

 *

 * <h3>Specification for implementors</h3>

 * This abstract class has two implementations, both of which are immutable and thread-safe.

 * One implementation models region-based IDs, the other is {@code ZoneOffset} modelling

 * offset-based IDs.

 *

 * @since 1.8

 */

public abstract class ZoneId implements Serializable {

    /**

     * A map of zone overrides to enable the older US time-zone names to be used.

     * <p>

     * This maps as follows:

     * <p><ul>

     * <li>EST - America/Indianapolis</li>

     * <li>MST - America/Phoenix</li>

     * <li>HST - Pacific/Honolulu</li>

     * <li>ACT - Australia/Darwin</li>

     * <li>AET - Australia/Sydney</li>

     * <li>AGT - America/Argentina/Buenos_Aires</li>

     * <li>ART - Africa/Cairo</li>

     * <li>AST - America/Anchorage</li>

     * <li>BET - America/Sao_Paulo</li>

     * <li>BST - Asia/Dhaka</li>

     * <li>CAT - Africa/Harare</li>

     * <li>CNT - America/St_Johns</li>

     * <li>CST - America/Chicago</li>

     * <li>CTT - Asia/Shanghai</li>

     * <li>EAT - Africa/Addis_Ababa</li>

     * <li>ECT - Europe/Paris</li>

     * <li>IET - America/Indiana/Indianapolis</li>

     * <li>IST - Asia/Kolkata</li>

     * <li>JST - Asia/Tokyo</li>

     * <li>MIT - Pacific/Apia</li>

     * <li>NET - Asia/Yerevan</li>

     * <li>NST - Pacific/Auckland</li>

     * <li>PLT - Asia/Karachi</li>

     * <li>PNT - America/Phoenix</li>

     * <li>PRT - America/Puerto_Rico</li>

     * <li>PST - America/Los_Angeles</li>

     * <li>SST - Pacific/Guadalcanal</li>

     * <li>VST - Asia/Ho_Chi_Minh</li>

     * </ul><p>

     * The map is unmodifiable.

     */

    public static final Map<String, String> OLD_IDS_PRE_2005;

    /**

     * A map of zone overrides to enable the older US time-zone names to be used.

     * <p>

     * This maps as follows:

     * <p><ul>

     * <li>EST - -05:00</li>

     * <li>HST - -10:00</li>

     * <li>MST - -07:00</li>

     * <li>ACT - Australia/Darwin</li>

     * <li>AET - Australia/Sydney</li>

     * <li>AGT - America/Argentina/Buenos_Aires</li>

     * <li>ART - Africa/Cairo</li>

     * <li>AST - America/Anchorage</li>

     * <li>BET - America/Sao_Paulo</li>

     * <li>BST - Asia/Dhaka</li>

     * <li>CAT - Africa/Harare</li>

     * <li>CNT - America/St_Johns</li>

     * <li>CST - America/Chicago</li>

     * <li>CTT - Asia/Shanghai</li>

     * <li>EAT - Africa/Addis_Ababa</li>

     * <li>ECT - Europe/Paris</li>

     * <li>IET - America/Indiana/Indianapolis</li>

     * <li>IST - Asia/Kolkata</li>

     * <li>JST - Asia/Tokyo</li>

     * <li>MIT - Pacific/Apia</li>

     * <li>NET - Asia/Yerevan</li>

     * <li>NST - Pacific/Auckland</li>

     * <li>PLT - Asia/Karachi</li>

     * <li>PNT - America/Phoenix</li>

     * <li>PRT - America/Puerto_Rico</li>

     * <li>PST - America/Los_Angeles</li>

     * <li>SST - Pacific/Guadalcanal</li>

     * <li>VST - Asia/Ho_Chi_Minh</li>

     * </ul><p>

     * The map is unmodifiable.

     */

    public static final Map<String, String> OLD_IDS_POST_2005;

    static {

        Map<String, String> base = new HashMap<>();

        base.put("ACT", "Australia/Darwin");

        base.put("AET", "Australia/Sydney");

        base.put("AGT", "America/Argentina/Buenos_Aires");

        base.put("ART", "Africa/Cairo");

        base.put("AST", "America/Anchorage");

        base.put("BET", "America/Sao_Paulo");

        base.put("BST", "Asia/Dhaka");

        base.put("CAT", "Africa/Harare");

        base.put("CNT", "America/St_Johns");

        base.put("CST", "America/Chicago");

        base.put("CTT", "Asia/Shanghai");

        base.put("EAT", "Africa/Addis_Ababa");

        base.put("ECT", "Europe/Paris");

        base.put("IET", "America/Indiana/Indianapolis");

        base.put("IST", "Asia/Kolkata");

        base.put("JST", "Asia/Tokyo");

        base.put("MIT", "Pacific/Apia");

        base.put("NET", "Asia/Yerevan");

        base.put("NST", "Pacific/Auckland");

        base.put("PLT", "Asia/Karachi");

        base.put("PNT", "America/Phoenix");

        base.put("PRT", "America/Puerto_Rico");

        base.put("PST", "America/Los_Angeles");

        base.put("SST", "Pacific/Guadalcanal");

        base.put("VST", "Asia/Ho_Chi_Minh");

        Map<String, String> pre = new HashMap<>(base);

        pre.put("EST", "America/Indianapolis");

        pre.put("MST", "America/Phoenix");

        pre.put("HST", "Pacific/Honolulu");

        OLD_IDS_PRE_2005 = Collections.unmodifiableMap(pre);

        Map<String, String> post = new HashMap<>(base);

        post.put("EST", "-05:00");

        post.put("MST", "-07:00");

        post.put("HST", "-10:00");

        OLD_IDS_POST_2005 = Collections.unmodifiableMap(post);

    }

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 8352817235686L;

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

    /**

     * Gets the system default time-zone.

     * <p>

     * This queries {@link TimeZone#getDefault()} to find the default time-zone

     * and converts it to a {@code ZoneId}. If the system default time-zone is changed,

     * then the result of this method will also change.

     *

     * @return the zone ID, not null

     * @throws DateTimeException if the converted zone ID has an invalid format

     * @throws java.time.zone.ZoneRulesException if the converted zone region ID cannot be found

     */

    public static ZoneId systemDefault() {

        return ZoneId.of(TimeZone.getDefault().getID(), OLD_IDS_POST_2005);

    }

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

    /**

     * Obtains an instance of {@code ZoneId} using its ID using a map

     * of aliases to supplement the standard zone IDs.

     * <p>

     * Many users of time-zones use short abbreviations, such as PST for

     * 'Pacific Standard Time' and PDT for 'Pacific Daylight Time'.

     * These abbreviations are not unique, and so cannot be used as IDs.

     * This method allows a map of string to time-zone to be setup and reused

     * within an application.

     *

     * @param zoneId  the time-zone ID, not null

     * @param aliasMap  a map of alias zone IDs (typically abbreviations) to real zone IDs, not null

     * @return the zone ID, not null

     * @throws DateTimeException if the zone ID has an invalid format

     * @throws java.time.zone.ZoneRulesException if the zone region ID cannot be found

     */

    public static ZoneId of(String zoneId, Map<String, String> aliasMap) {

        Objects.requireNonNull(zoneId, "zoneId");

        Objects.requireNonNull(aliasMap, "aliasMap");

        String id = aliasMap.get(zoneId);

        id = (id != null ? id : zoneId);

        return of(id);

    }

    /**

     * Obtains an instance of {@code ZoneId} from an ID ensuring that the

     * ID is valid and available for use.

     * <p>

     * This method parses the ID, applies any appropriate normalization, and validates it

     * against the known set of IDs for which rules are available.

     * <p>

     * An ID is parsed as though it is an offset ID if it starts with 'UTC', 'GMT', '+'

     * or '-', or if it has less then two letters.

     * The offset of {@link ZoneOffset#UTC zero} may be represented in multiple ways,

     * including 'Z', 'UTC', 'GMT', 'UTC0' 'GMT0', '+00:00', '-00:00' and 'UTC+00:00'.

     * <p>

     * Eight forms of ID are recognized, where '{offset}' means to parse using {@link ZoneOffset#of(String)}:

     * <p><ul>

     * <li><code>{offset}</code> - a {@link ZoneOffset} ID, such as 'Z' or '+02:00'

     * <li><code>UTC</code> - alternate form of a {@code ZoneOffset} ID equal to 'Z'

     * <li><code>UTC0</code> - alternate form of a {@code ZoneOffset} ID equal to 'Z'

     * <li><code>UTC{offset}</code> - alternate form of a {@code ZoneOffset} ID equal to '{offset}'

     * <li><code>GMT</code> - alternate form of a {@code ZoneOffset} ID equal to 'Z'

     * <li><code>GMT0</code> - alternate form of a {@code ZoneOffset} ID equal to 'Z'

     * <li><code>GMT{offset}</code> - alternate form of a {@code ZoneOffset} ID equal to '{offset}'r

     * <li><code>{regionID}</code> - full region ID, loaded from configuration

     * </ul><p>

     * Region IDs must match the regular expression <code>[A-Za-z][A-Za-z0-9~/._+-]+</code>.

     * <p>

     * The detailed format of the region ID depends on the group supplying the data.

     * The default set of data is supplied by the IANA Time Zone Database (TZDB)

     * This has region IDs of the form '{area}/{city}', such as 'Europe/Paris' or 'America/New_York'.

     * This is compatible with most IDs from {@link java.util.TimeZone}.

     *

     * @param zoneId  the time-zone ID, not null

     * @return the zone ID, not null

     * @throws DateTimeException if the zone ID has an invalid format

     * @throws java.time.zone.ZoneRulesException if the zone region ID cannot be found

     */

    public static ZoneId of(String zoneId) {

        Objects.requireNonNull(zoneId, "zoneId");

        if (zoneId.length() <= 1 || zoneId.startsWith("+") || zoneId.startsWith("-")) {

            return ZoneOffset.of(zoneId);

        } else if (zoneId.startsWith("UTC") || zoneId.startsWith("GMT")) {

            if (zoneId.length() == 3 || (zoneId.length() == 4 && zoneId.charAt(3) == '0')) {

                return ZoneOffset.UTC;

            }

            return ZoneOffset.of(zoneId.substring(3));

        }

        return ZoneRegion.ofId(zoneId, true);

    }

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

    /**

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

     * <p>

     * A {@code TemporalAccessor} represents some form of date and time information.

     * This factory converts the arbitrary temporal object to an instance of {@code ZoneId}.

     * <p>

     * The conversion will try to obtain the zone in a way that favours region-based

     * zones over offset-based zones using {@link Queries#zone()}.

     * <p>

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

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

     *

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

     * @return the zone ID, not null

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

     */

    public static ZoneId from(TemporalAccessor temporal) {

        ZoneId obj = temporal.query(Queries.zone());

        if (obj == null) {

            throw new DateTimeException("Unable to obtain ZoneId from TemporalAccessor: " + temporal.getClass());

        }

        return obj;

    }

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

    /**

     * Constructor only accessible within the package.

     */

    ZoneId() {

        if (getClass() != ZoneOffset.class && getClass() != ZoneRegion.class) {

            throw new AssertionError("Invalid subclass");

        }

    }

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

    /**

     * Gets the unique time-zone ID.

     * <p>

     * This ID uniquely defines this object.

     * The format of an offset based ID is defined by {@link ZoneOffset#getId()}.

     *

     * @return the time-zone unique ID, not null

     */

    public abstract String getId();

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

    /**

     * Gets the time-zone rules for this ID allowing calculations to be performed.

     * <p>

     * The rules provide the functionality associated with a time-zone,

     * such as finding the offset for a given instant or local date-time.

     * <p>

     * A time-zone can be invalid if it is deserialized in a JVM which does not

     * have the same rules loaded as the JVM that stored it. In this case, calling

     * this method will throw an exception.

     * <p>

     * The rules are supplied by {@link ZoneRulesProvider}. An advanced provider may

     * support dynamic updates to the rules without restarting the JVM.

     * If so, then the result of this method may change over time.

     * Each individual call will be still remain thread-safe.

     * <p>

     * {@link ZoneOffset} will always return a set of rules where the offset never changes.

     *

     * @return the rules, not null

     * @throws DateTimeException if no rules are available for this ID

     */

    public abstract ZoneRules getRules();

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

    /**

     * Gets the textual representation of the zone, such as 'British Time' or

     * '+02:00'.

     * <p>

     * This returns a textual description for the time-zone ID.

     * <p>

     * If no textual mapping is found then the {@link #getId() full ID} 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 zone, not null

     */

    public String getText(TextStyle style, Locale locale) {

        return new DateTimeFormatterBuilder().appendZoneText(style).toFormatter(locale).print(new TemporalAccessor() {

            @Override

            public boolean isSupported(TemporalField field) {

                return false;

            }

            @Override

            public long getLong(TemporalField field) {

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

            }

            @SuppressWarnings("unchecked")

            @Override

            public <R> R query(TemporalQuery<R> query) {

                if (query == Queries.zoneId()) {

                    return (R) ZoneId.this;

                }

                return TemporalAccessor.super.query(query);

            }

        });

    }

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

    /**

     * Checks if this time-zone ID is equal to another time-zone ID.

     * <p>

     * The comparison is based on the ID.

     *

     * @param obj  the object to check, null returns false

     * @return true if this is equal to the other time-zone ID

     */

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

           return true;

        }

        if (obj instanceof ZoneId) {

            ZoneId other = (ZoneId) obj;

            return getId().equals(other.getId());

        }

        return false;

    }

    /**

     * A hash code for this time-zone ID.

     *

     * @return a suitable hash code

     */

    @Override

    public int hashCode() {

        return getId().hashCode();

    }

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

    /**

     * Outputs this zone as a {@code String}, using the ID.

     *

     * @return a string representation of this time-zone ID, not null

     */

    @Override

    public String toString() {

        return getId();

    }

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

    /**

     * Writes the object using a

     * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.

     * <pre>

     *  out.writeByte(7);  // identifies this as a ZoneId (not ZoneOffset)

     *  out.writeUTF(zoneId);

     * </pre>

     *

     * @return the instance of {@code Ser}, not null

     */

    // this is here for serialization Javadoc

    private Object writeReplace() {

        return new Ser(Ser.ZONE_REGION_TYPE, this);

    }

    abstract void write(DataOutput out) throws IOException;

}