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/*
 * 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.
 *
 * * 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,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package java.time;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.zone.ZoneRules;
import java.time.zone.ZoneRulesException;
import java.time.zone.ZoneRulesProvider;
import java.util.Objects;

/**
 * A geographical region where the same time-zone rules apply.
 * <p>
 * Time-zone information is categorized as a set of rules defining when and
 * how the offset from UTC/Greenwich changes. These rules are accessed using
 * identifiers based on geographical regions, such as countries or states.
 * The most common region classification is the Time Zone Database (TZDB),
 * which defines regions such as 'Europe/Paris' and 'Asia/Tokyo'.
 * <p>
 * The region identifier, modeled by this class, is distinct from the
 * underlying rules, modeled by {@link ZoneRules}.
 * The rules are defined by governments and change frequently.
 * By contrast, the region identifier is well-defined and long-lived.
 * This separation also allows rules to be shared between regions if appropriate.
 *
 * @implSpec
 * This class is immutable and thread-safe.
 *
 * @since 1.8
 */
final class ZoneRegion extends ZoneId implements Serializable {

 /**
 * Serialization version.
 */
 private static final long serialVersionUID = 8386373296231747096L;
 /**
 * The time-zone ID, not null.
 */
 private final String id;
 /**
 * The time-zone rules, null if zone ID was loaded leniently.
 */
 private final transient ZoneRules rules;

 /**
 * Obtains an instance of {@code ZoneId} from an identifier.
 *
 * @param zoneId the time-zone ID, not null
 * @param checkAvailable whether to check if the zone ID is available
 * @return the zone ID, not null
 * @throws DateTimeException if the ID format is invalid
 * @throws ZoneRulesException if checking availability and the ID cannot be found
 */
 static ZoneRegion ofId(String zoneId, boolean checkAvailable) {
 Objects.requireNonNull(zoneId, "zoneId");
 checkName(zoneId);
 ZoneRules rules = null;
 try {
 // always attempt load for better behavior after deserialization
 rules = ZoneRulesProvider.getRules(zoneId, true);
 } catch (ZoneRulesException ex) {
 if (checkAvailable) {
 throw ex;
 }
 }
 return new ZoneRegion(zoneId, rules);
 }

 /**
 * Checks that the given string is a legal ZondId name.
 *
 * @param zoneId the time-zone ID, not null
 * @throws DateTimeException if the ID format is invalid
 */
 private static void checkName(String zoneId) {
 int n = zoneId.length();
 if (n < 2) {
 throw new DateTimeException("Invalid ID for region-based ZoneId, invalid format: " + zoneId);
 }
 for (int i = 0; i < n; i++) {
 char c = zoneId.charAt(i);
 if (c >= 'a' && c <= 'z') continue;
 if (c >= 'A' && c <= 'Z') continue;
 if (c == '/' && i != 0) continue;
 if (c >= '0' && c <= '9' && i != 0) continue;
 if (c == '~' && i != 0) continue;
 if (c == '.' && i != 0) continue;
 if (c == '_' && i != 0) continue;
 if (c == '+' && i != 0) continue;
 if (c == '-' && i != 0) continue;
 throw new DateTimeException("Invalid ID for region-based ZoneId, invalid format: " + zoneId);
 }
 }

 //-------------------------------------------------------------------------
 /**
 * Constructor.
 *
 * @param id the time-zone ID, not null
 * @param rules the rules, null for lazy lookup
 */
 ZoneRegion(String id, ZoneRules rules) {
 this.id = id;
 this.rules = rules;
 }

 //-----------------------------------------------------------------------
 @Override
 public String getId() {
 return id;
 }

 @Override
 public ZoneRules getRules() {
 // additional query for group provider when null allows for possibility
 // that the provider was updated after the ZoneId was created
 return (rules != null ? rules : ZoneRulesProvider.getRules(id, false));
 }

 //-----------------------------------------------------------------------
 /**
 * Writes the object using a
 * <a href="{@docRoot}/serialized-form.html#java.time.Ser">dedicated serialized form</a>.
 * @serialData
 * <pre>
 * out.writeByte(7); // identifies a ZoneId (not ZoneOffset)
 * out.writeUTF(zoneId);
 * </pre>
 *
 * @return the instance of {@code Ser}, not null
 */
 private Object writeReplace() {
 return new Ser(Ser.ZONE_REGION_TYPE, this);
 }

 /**
 * Defend against malicious streams.
 *
 * @param s the stream to read
 * @throws InvalidObjectException always
 */
 private void readObject(ObjectInputStream s) throws InvalidObjectException {
 throw new InvalidObjectException("Deserialization via serialization delegate");
 }

 @Override
 void write(DataOutput out) throws IOException {
 out.writeByte(Ser.ZONE_REGION_TYPE);
 writeExternal(out);
 }

 void writeExternal(DataOutput out) throws IOException {
 out.writeUTF(id);
 }

 static ZoneId readExternal(DataInput in) throws IOException {
 String id = in.readUTF();
 return ZoneId.of(id, false);
 }

}