ZoneRegion.java
/*
* Copyright (c) 2007-present, 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
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package org.threeten.bp;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.regex.Pattern;
import org.threeten.bp.jdk8.Jdk8Methods;
import org.threeten.bp.zone.ZoneRules;
import org.threeten.bp.zone.ZoneRulesException;
import org.threeten.bp.zone.ZoneRulesProvider;
/**
* 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.
*
* <h3>Specification for implementors</h3>
* This class is immutable and thread-safe.
*/
final class ZoneRegion extends ZoneId implements Serializable {
/**
* Serialization version.
*/
private static final long serialVersionUID = 8386373296231747096L;
/**
* The regex pattern for region IDs.
*/
private static final Pattern PATTERN = Pattern.compile("[A-Za-z][A-Za-z0-9~/._+-]+");
/**
* 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 ZoneRegion} from an identifier without checking
* if the time-zone has available rules.
* <p>
* This method parses the ID and applies any appropriate normalization.
* It does not validate the ID against the known set of IDsfor which rules are available.
* <p>
* This method is intended for advanced use cases.
* For example, consider a system that always retrieves time-zone rules from a remote server.
* Using this factory would allow a {@code ZoneRegion}, and thus a {@code ZonedDateTime},
* to be created without loading the rules from the remote server.
*
* @param zoneId the time-zone ID, not null
* @return the zone ID, not null
* @throws DateTimeException if the ID format is invalid
*/
private static ZoneRegion ofLenient(String zoneId) {
if (zoneId.equals("Z") || zoneId.startsWith("+") || zoneId.startsWith("-")) {
throw new DateTimeException("Invalid ID for region-based ZoneId, invalid format: " + zoneId);
}
if (zoneId.equals("UTC") || zoneId.equals("GMT") || zoneId.equals("UT")) {
return new ZoneRegion(zoneId, ZoneOffset.UTC.getRules());
}
if (zoneId.startsWith("UTC+") || zoneId.startsWith("GMT+") ||
zoneId.startsWith("UTC-") || zoneId.startsWith("GMT-")) {
ZoneOffset offset = ZoneOffset.of(zoneId.substring(3));
if (offset.getTotalSeconds() == 0) {
return new ZoneRegion(zoneId.substring(0, 3), offset.getRules());
}
return new ZoneRegion(zoneId.substring(0, 3) + offset.getId(), offset.getRules());
}
if (zoneId.startsWith("UT+") || zoneId.startsWith("UT-")) {
ZoneOffset offset = ZoneOffset.of(zoneId.substring(2));
if (offset.getTotalSeconds() == 0) {
return new ZoneRegion("UT", offset.getRules());
}
return new ZoneRegion("UT" + offset.getId(), offset.getRules());
}
return ofId(zoneId, false);
}
/**
* 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 DateTimeException if checking availability and the ID cannot be found
*/
static ZoneRegion ofId(String zoneId, boolean checkAvailable) {
Jdk8Methods.requireNonNull(zoneId, "zoneId");
if (zoneId.length() < 2 || PATTERN.matcher(zoneId).matches() == false) {
throw new DateTimeException("Invalid ID for region-based ZoneId, invalid format: " + zoneId);
}
ZoneRules rules = null;
try {
// always attempt load for better behavior after deserialization
rules = ZoneRulesProvider.getRules(zoneId, true);
} catch (ZoneRulesException ex) {
// special case as removed from data file
if (zoneId.equals("GMT0")) {
rules = ZoneOffset.UTC.getRules();
} else if (checkAvailable) {
throw ex;
}
}
return new ZoneRegion(zoneId, rules);
}
//-------------------------------------------------------------------------
/**
* 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 added after the ZoneId was created
return (rules != null ? rules : ZoneRulesProvider.getRules(id, false));
}
//-----------------------------------------------------------------------
private Object writeReplace() {
return new Ser(Ser.ZONE_REGION_TYPE, this);
}
/**
* Defend against malicious streams.
* @return never
* @throws InvalidObjectException always
*/
private Object readResolve() throws ObjectStreamException {
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 ofLenient(id);
}
}