TimeZone.java
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
* @(#)TimeZone.java 1.51 00/01/19
*
* Copyright (C) 1996-2016, International Business Machines
* Corporation and others. All Rights Reserved.
*/
package com.ibm.icu.util;
import com.ibm.icu.impl.Grego;
import com.ibm.icu.impl.ICUConfig;
import com.ibm.icu.impl.ICUData;
import com.ibm.icu.impl.ICUResourceBundle;
import com.ibm.icu.impl.JavaTimeZone;
import com.ibm.icu.impl.TimeZoneAdapter;
import com.ibm.icu.impl.ZoneMeta;
import com.ibm.icu.text.TimeZoneFormat;
import com.ibm.icu.text.TimeZoneFormat.Style;
import com.ibm.icu.text.TimeZoneFormat.TimeType;
import com.ibm.icu.text.TimeZoneNames;
import com.ibm.icu.text.TimeZoneNames.NameType;
import com.ibm.icu.util.ULocale.Category;
import java.io.Serializable;
import java.util.Date;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.Set;
import java.util.logging.Logger;
/**
* {@icuenhanced java.util.TimeZone}.{@icu _usage_}
*
* <p><code>TimeZone</code> represents a time zone offset, and also computes daylight savings.
*
* <p>Typically, you get a <code>TimeZone</code> using {@link #getDefault()} which creates a <code>
* TimeZone</code> based on the time zone where the program is running. For example, for a program
* running in Japan, <code>getDefault</code> creates a <code>TimeZone</code> object based on
* Japanese Standard Time.
*
* <p>You can also get a <code>TimeZone</code> using {@link #getTimeZone(String)} along with a time
* zone ID. For instance, the time zone ID for the U.S. Pacific Time zone is "America/Los_Angeles".
* So, you can get a U.S. Pacific Time <code>TimeZone</code> object with:
*
* <blockquote>
*
* <pre>
* TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
* </pre>
*
* </blockquote>
*
* You can use the {@link #getAvailableIDs()} method to iterate through all the supported time zone
* IDs, or getCanonicalID method to check if a time zone ID is supported or not. You can then choose
* a supported ID to get a <code>TimeZone</code>. If the time zone you want is not represented by
* one of the supported IDs, then you can create a custom time zone ID with the following syntax:
*
* <blockquote>
*
* <pre>
* GMT[+|-]hh[[:]mm]
* </pre>
*
* </blockquote>
*
* For example, you might specify GMT+14:00 as a custom time zone ID. The <code>TimeZone</code> that
* is returned when you specify a custom time zone ID uses the specified offset from GMT(=UTC) and
* does not observe daylight saving time. For example, you might specify GMT+14:00 as a custom time
* zone ID to create a TimeZone representing 14 hours ahead of GMT (with no daylight saving time).
* In addition, <code>getCanonicalID</code> can also be used to normalize a custom time zone ID.
*
* <p>For compatibility with JDK 1.1.x, some other three-letter time zone IDs (such as "PST", "CTT",
* "AST") are also supported. However, <strong>their use is deprecated</strong> because the same
* abbreviation is often used for multiple time zones (for example, "CST" could be U.S. "Central
* Standard Time" and "China Standard Time"), and the Java platform can then only recognize one of
* them.
*
* <p><strong>Note:</strong> Starting from ICU4J 4.0, you can optionally choose JDK <code>TimeZone
* </code> as the time zone implementation. The TimeZone factory method <code>getTimeZone</code>
* creates an instance of ICU's own <code>TimeZone</code> subclass by default. If you want to use
* the JDK implementation always, you can set the default time zone implementation type by the new
* method <code>setDefaultTimeZoneType</code>. Alternatively, you can change the initial default
* implementation type by setting a property below.
*
* <blockquote>
*
* <pre>
* #
* # The default TimeZone implementation type used by the ICU TimeZone
* # factory method. [ ICU | JDK ]
* #
* com.ibm.icu.util.TimeZone.DefaultTimeZoneType = ICU
* </pre>
*
* </blockquote>
*
* <p>This property is included in ICUConfig.properties in com.ibm.icu package. When the <code>
* TimeZone</code> class is loaded, the initialization code checks if the property <code>
* com.ibm.icu.util.TimeZone.DefaultTimeZoneType=xxx</code> is defined by the system properties. If
* not available, then it loads ICUConfig.properties to get the default time zone implementation
* type. The property setting is only used for the initial default value and you can change the
* default type by calling <code>setDefaultTimeZoneType</code> at runtime.
*
* @see Calendar
* @see GregorianCalendar
* @see SimpleTimeZone
* @author Mark Davis, Deborah Goldsmith, Chen-Lieh Huang, Alan Liu
* @stable ICU 2.0
*/
public abstract class TimeZone implements Serializable, Cloneable, Freezable<TimeZone> {
/** Logger instance for this class */
private static final Logger LOGGER = Logger.getLogger("com.ibm.icu.util.TimeZone");
// using serialver from jdk1.4.2_05
private static final long serialVersionUID = -744942128318337471L;
/**
* Default constructor. (For invocation by subclass constructors, typically implicit.)
*
* @stable ICU 2.8
*/
public TimeZone() {}
/**
* Constructing a TimeZone with the given time zone ID.
*
* @param ID the time zone ID.
* @internal
* @deprecated This API is ICU internal only.
*/
@Deprecated
protected TimeZone(String ID) {
if (ID == null) {
throw new NullPointerException();
}
this.ID = ID;
}
/**
* {@icu} A time zone implementation type indicating ICU's own TimeZone used by <code>
* getTimeZone</code>, <code>setDefaultTimeZoneType</code> and <code>getDefaultTimeZoneType
* </code>.
*
* @stable ICU 4.0
*/
public static final int TIMEZONE_ICU = 0;
/**
* {@icu} A time zone implementation type indicating the {@link java.util.TimeZone} used by
* <code>getTimeZone</code>, <code>setDefaultTimeZoneType</code> and <code>
* getDefaultTimeZoneType</code>.
*
* @stable ICU 4.0
*/
public static final int TIMEZONE_JDK = 1;
/**
* A style specifier for <code>getDisplayName()</code> indicating a short name, such as "PST."
*
* @see #LONG
* @stable ICU 2.0
*/
public static final int SHORT = 0;
/**
* A style specifier for <code>getDisplayName()</code> indicating a long name, such as "Pacific
* Standard Time."
*
* @see #SHORT
* @stable ICU 2.0
*/
public static final int LONG = 1;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a short generic name,
* such as "PT."
*
* @see #LONG_GENERIC
* @stable ICU 4.4
*/
public static final int SHORT_GENERIC = 2;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a long generic name,
* such as "Pacific Time."
*
* @see #SHORT_GENERIC
* @stable ICU 4.4
*/
public static final int LONG_GENERIC = 3;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a short name derived
* from the timezone's offset, such as "-0800."
*
* @see #LONG_GMT
* @stable ICU 4.4
*/
public static final int SHORT_GMT = 4;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a long name derived
* from the timezone's offset, such as "GMT-08:00."
*
* @see #SHORT_GMT
* @stable ICU 4.4
*/
public static final int LONG_GMT = 5;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a short name derived
* from the timezone's short standard or daylight timezone name ignoring commonlyUsed, such as
* "PDT."
*
* @stable ICU 4.4
*/
public static final int SHORT_COMMONLY_USED = 6;
/**
* {@icu} A style specifier for <code>getDisplayName()</code> indicating a long name derived
* from the timezone's fallback name, such as "United States (Los Angeles)."
*
* @stable ICU 4.4
*/
public static final int GENERIC_LOCATION = 7;
/**
* {@icu} The time zone ID reserved for unknown time zone.
*
* @see #getTimeZone(String)
* @stable ICU 4.8
*/
public static final String UNKNOWN_ZONE_ID = "Etc/Unknown";
/** The canonical ID for GMT(UTC) time zone. */
static final String GMT_ZONE_ID = "Etc/GMT";
/**
* {@icu} The immutable (frozen) "unknown" time zone. It behaves like the GMT/UTC time zone but
* has the UNKNOWN_ZONE_ID = "Etc/Unknown". {@link TimeZone#getTimeZone(String)} returns a
* mutable clone of this time zone if the input ID is not recognized.
*
* @see #UNKNOWN_ZONE_ID
* @see #getTimeZone(String)
* @stable ICU 49
*/
public static final TimeZone UNKNOWN_ZONE = new ConstantZone(0, UNKNOWN_ZONE_ID).freeze();
/**
* {@icu} The immutable GMT (=UTC) time zone. Its ID is "Etc/GMT".
*
* @stable ICU 49
*/
public static final TimeZone GMT_ZONE = new ConstantZone(0, GMT_ZONE_ID).freeze();
/**
* {@icu} System time zone type constants used by filtering zones in {@link
* TimeZone#getAvailableIDs(SystemTimeZoneType, String, Integer)}
*
* @stable ICU 4.8
*/
public enum SystemTimeZoneType {
/**
* Any system zones.
*
* @stable ICU 4.8
*/
ANY,
/**
* Canonical system zones.
*
* @stable ICU 4.8
*/
CANONICAL,
/**
* Canonical system zones associated with actual locations.
*
* @stable ICU 4.8
*/
CANONICAL_LOCATION,
}
/**
* Gets the time zone offset, for current date, modified in case of daylight savings. This is
* the offset to add <i>to</i> UTC to get local time.
*
* @param era the era of the given date.
* @param year the year in the given date.
* @param month the month in the given date. Month is 0-based. e.g., 0 for January.
* @param day the day-in-month of the given date.
* @param dayOfWeek the day-of-week of the given date.
* @param milliseconds the millis in day in <em>standard</em> local time.
* @return the offset to add <i>to</i> GMT to get local time.
* @stable ICU 2.0
*/
public abstract int getOffset(
int era, int year, int month, int day, int dayOfWeek, int milliseconds);
/**
* Returns the offset of this time zone from UTC at the specified date. If Daylight Saving Time
* is in effect at the specified date, the offset value is adjusted with the amount of daylight
* saving.
*
* @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
* @return the amount of time in milliseconds to add to UTC to get local time.
* @see Calendar#ZONE_OFFSET
* @see Calendar#DST_OFFSET
* @see #getOffset(long, boolean, int[])
* @stable ICU 2.8
*/
public int getOffset(long date) {
int[] result = new int[2];
getOffset(date, false, result);
return result[0] + result[1];
}
/**
* Returns the time zone raw and GMT offset for the given moment in time. Upon return,
* local-millis = GMT-millis + rawOffset + dstOffset. All computations are performed in the
* proleptic Gregorian calendar. The default implementation in the TimeZone class delegates to
* the 8-argument getOffset().
*
* @param date moment in time for which to return offsets, in units of milliseconds from January
* 1, 1970 0:00 GMT, either GMT time or local wall time, depending on {@code local}.
* @param local if true, {@code date} is local wall time; otherwise it is in GMT time.
* @param offsets output parameter to receive the raw offset, that is, the offset not including
* DST adjustments, in offsets[0], and the DST offset, that is, the offset to be added to
* {@code rawOffset} to obtain the total offset between local and GMT time, in offsets[1].
* If DST is not in effect, the DST offset is zero; otherwise it is a positive value,
* typically one hour.
* @stable ICU 2.8
*/
public void getOffset(long date, boolean local, int[] offsets) {
offsets[0] = getRawOffset();
if (!local) {
date += offsets[0]; // now in local standard millis
}
// When local == true, date might not be in local standard
// millis. getOffset taking 6 parameters used here assume
// the given time in day is local standard time.
// At STD->DST transition, there is a range of time which
// does not exist. When 'date' is in this time range
// (and local == true), this method interprets the specified
// local time as DST. At DST->STD transition, there is a
// range of time which occurs twice. In this case, this
// method interprets the specified local time as STD.
// To support the behavior above, we need to call getOffset
// (with 6 args) twice when local == true and DST is
// detected in the initial call.
int fields[] = new int[6];
for (int pass = 0; ; pass++) {
Grego.timeToFields(date, fields);
offsets[1] =
getOffset(
GregorianCalendar.AD,
fields[0],
fields[1],
fields[2],
fields[3],
fields[5])
- offsets[0];
if (pass != 0 || !local || offsets[1] == 0) {
break;
}
// adjust to local standard millis
date -= offsets[1];
}
}
/**
* Sets the base time zone offset to GMT. This is the offset to add <i>to</i> UTC to get local
* time.
*
* @param offsetMillis the given base time zone offset to GMT.
* @stable ICU 2.0
*/
public abstract void setRawOffset(int offsetMillis);
/**
* Gets unmodified offset, NOT modified in case of daylight savings. This is the offset to add
* <i>to</i> UTC to get local time.
*
* @return the unmodified offset to add <i>to</i> UTC to get local time.
* @stable ICU 2.0
*/
public abstract int getRawOffset();
/**
* Gets the ID of this time zone.
*
* @return the ID of this time zone.
* @stable ICU 2.0
*/
public String getID() {
return ID;
}
/**
* Sets the time zone ID. This does not change any other data in the time zone object.
*
* @param ID the new time zone ID.
* @stable ICU 2.0
*/
public void setID(String ID) {
if (ID == null) {
throw new NullPointerException();
}
if (isFrozen()) {
throw new UnsupportedOperationException(
"Attempt to modify a frozen TimeZone instance.");
}
this.ID = ID;
}
/**
* Returns a name of this time zone suitable for presentation to the user in the default <code>
* DISPLAY</code> locale. This method returns the long generic name. If the display name is not
* available for the locale, a fallback based on the country, city, or time zone id will be
* used.
*
* @return the human-readable name of this time zone in the default locale.
* @see Category#DISPLAY
* @stable ICU 2.0
*/
public final String getDisplayName() {
return _getDisplayName(LONG_GENERIC, false, ULocale.getDefault(Category.DISPLAY));
}
/**
* Returns a name of this time zone suitable for presentation to the user in the specified
* locale. This method returns the long generic name. If the display name is not available for
* the locale, a fallback based on the country, city, or time zone id will be used.
*
* @param locale the locale in which to supply the display name.
* @return the human-readable name of this time zone in the given locale or in the default
* locale if the given locale is not recognized.
* @stable ICU 2.0
*/
public final String getDisplayName(Locale locale) {
return _getDisplayName(LONG_GENERIC, false, ULocale.forLocale(locale));
}
/**
* Returns a name of this time zone suitable for presentation to the user in the specified
* locale. This method returns the long name, not including daylight savings. If the display
* name is not available for the locale, a fallback based on the country, city, or time zone id
* will be used.
*
* @param locale the ulocale in which to supply the display name.
* @return the human-readable name of this time zone in the given locale or in the default
* ulocale if the given ulocale is not recognized.
* @stable ICU 3.2
*/
public final String getDisplayName(ULocale locale) {
return _getDisplayName(LONG_GENERIC, false, locale);
}
/**
* Returns a name of this time zone suitable for presentation to the user in the default <code>
* DISPLAY</code> locale. If the display name is not available for the locale, then this method
* returns a string in the localized GMT offset format such as <code>GMT[+-]HH:mm</code>.
*
* @param daylight if true, return the daylight savings name.
* @param style the output style of the display name. Valid styles are <code>SHORT</code>,
* <code>LONG</code>, <code>SHORT_GENERIC</code>, <code>LONG_GENERIC</code>, <code>SHORT_GMT
* </code>, <code>LONG_GMT</code>, <code>SHORT_COMMONLY_USED</code> or <code>
* GENERIC_LOCATION</code>.
* @return the human-readable name of this time zone in the default locale.
* @see Category#DISPLAY
* @stable ICU 2.0
*/
public final String getDisplayName(boolean daylight, int style) {
return getDisplayName(daylight, style, ULocale.getDefault(Category.DISPLAY));
}
/**
* Returns a name of this time zone suitable for presentation to the user in the specified
* locale. If the display name is not available for the locale, then this method returns a
* string in the localized GMT offset format such as <code>GMT[+-]HH:mm</code>.
*
* @param daylight if true, return the daylight savings name.
* @param style the output style of the display name. Valid styles are <code>SHORT</code>,
* <code>LONG</code>, <code>SHORT_GENERIC</code>, <code>LONG_GENERIC</code>, <code>SHORT_GMT
* </code>, <code>LONG_GMT</code>, <code>SHORT_COMMONLY_USED</code> or <code>
* GENERIC_LOCATION</code>.
* @param locale the locale in which to supply the display name.
* @return the human-readable name of this time zone in the given locale or in the default
* locale if the given locale is not recognized.
* @exception IllegalArgumentException style is invalid.
* @stable ICU 2.0
*/
public String getDisplayName(boolean daylight, int style, Locale locale) {
return getDisplayName(daylight, style, ULocale.forLocale(locale));
}
/**
* Returns a name of this time zone suitable for presentation to the user in the specified
* locale. If the display name is not available for the locale, then this method returns a
* string in the localized GMT offset format such as <code>GMT[+-]HH:mm</code>.
*
* @param daylight if true, return the daylight savings name.
* @param style the output style of the display name. Valid styles are <code>SHORT</code>,
* <code>LONG</code>, <code>SHORT_GENERIC</code>, <code>LONG_GENERIC</code>, <code>SHORT_GMT
* </code>, <code>LONG_GMT</code>, <code>SHORT_COMMONLY_USED</code> or <code>
* GENERIC_LOCATION</code>.
* @param locale the locale in which to supply the display name.
* @return the human-readable name of this time zone in the given locale or in the default
* locale if the given locale is not recognized.
* @exception IllegalArgumentException style is invalid.
* @stable ICU 3.2
*/
public String getDisplayName(boolean daylight, int style, ULocale locale) {
if (style < SHORT || style > GENERIC_LOCATION) {
throw new IllegalArgumentException("Illegal style: " + style);
}
return _getDisplayName(style, daylight, locale);
}
/**
* internal version (which is called by public APIs) accepts SHORT, LONG, SHORT_GENERIC,
* LONG_GENERIC, SHORT_GMT, LONG_GMT, SHORT_COMMONLY_USED and GENERIC_LOCATION.
*/
private String _getDisplayName(int style, boolean daylight, ULocale locale) {
if (locale == null) {
throw new NullPointerException("locale is null");
}
String result = null;
if (style == GENERIC_LOCATION || style == LONG_GENERIC || style == SHORT_GENERIC) {
// Generic format
TimeZoneFormat tzfmt = TimeZoneFormat.getInstance(locale);
long date = System.currentTimeMillis();
Output<TimeType> timeType = new Output<>(TimeType.UNKNOWN);
switch (style) {
case GENERIC_LOCATION:
result = tzfmt.format(Style.GENERIC_LOCATION, this, date, timeType);
break;
case LONG_GENERIC:
result = tzfmt.format(Style.GENERIC_LONG, this, date, timeType);
break;
case SHORT_GENERIC:
result = tzfmt.format(Style.GENERIC_SHORT, this, date, timeType);
break;
}
// Generic format many use Localized GMT as the final fallback.
// When Localized GMT format is used, the result might not be
// appropriate for the requested daylight value.
if (daylight && timeType.value == TimeType.STANDARD
|| !daylight && timeType.value == TimeType.DAYLIGHT) {
int offset = daylight ? getRawOffset() + getDSTSavings() : getRawOffset();
result =
(style == SHORT_GENERIC)
? tzfmt.formatOffsetShortLocalizedGMT(offset)
: tzfmt.formatOffsetLocalizedGMT(offset);
}
} else if (style == LONG_GMT || style == SHORT_GMT) {
// Offset format
TimeZoneFormat tzfmt = TimeZoneFormat.getInstance(locale);
int offset =
daylight && useDaylightTime()
? getRawOffset() + getDSTSavings()
: getRawOffset();
switch (style) {
case LONG_GMT:
result = tzfmt.formatOffsetLocalizedGMT(offset);
break;
case SHORT_GMT:
result = tzfmt.formatOffsetISO8601Basic(offset, false, false, false);
break;
}
} else {
// Specific format
assert (style == LONG || style == SHORT || style == SHORT_COMMONLY_USED);
// Gets the name directly from TimeZoneNames
long date = System.currentTimeMillis();
TimeZoneNames tznames = TimeZoneNames.getInstance(locale);
NameType nameType = null;
switch (style) {
case LONG:
nameType = daylight ? NameType.LONG_DAYLIGHT : NameType.LONG_STANDARD;
break;
case SHORT:
case SHORT_COMMONLY_USED:
nameType = daylight ? NameType.SHORT_DAYLIGHT : NameType.SHORT_STANDARD;
break;
}
result = tznames.getDisplayName(ZoneMeta.getCanonicalCLDRID(this), nameType, date);
if (result == null) {
// Fallback to localized GMT
TimeZoneFormat tzfmt = TimeZoneFormat.getInstance(locale);
int offset =
daylight && useDaylightTime()
? getRawOffset() + getDSTSavings()
: getRawOffset();
result =
(style == LONG)
? tzfmt.formatOffsetLocalizedGMT(offset)
: tzfmt.formatOffsetShortLocalizedGMT(offset);
}
}
assert (result != null);
return result;
}
/**
* Returns the amount of time to be added to local standard time to get local wall clock time.
*
* <p>The default implementation always returns 3600000 milliseconds (i.e., one hour) if this
* time zone observes Daylight Saving Time. Otherwise, 0 (zero) is returned.
*
* <p>If an underlying TimeZone implementation subclass supports historical Daylight Saving Time
* changes, this method returns the known latest daylight saving value.
*
* @return the amount of saving time in milliseconds
* @stable ICU 2.8
*/
public int getDSTSavings() {
if (useDaylightTime()) {
return 3600000;
}
return 0;
}
/**
* Queries if this time zone uses daylight savings time.
*
* @return true if this time zone uses daylight savings time, false, otherwise.
* <p><strong>Note:</strong>The default implementation of ICU TimeZone uses the tz database,
* which supports historic rule changes, for system time zones. With the implementation,
* there are time zones that used daylight savings time in the past, but no longer used
* currently. For example, Asia/Tokyo has never used daylight savings time since 1951. Most
* clients would expect that this method to return <code>false</code> for such case. The
* default implementation of this method returns <code>true</code> when the time zone uses
* daylight savings time in the current (Gregorian) calendar year.
* @stable ICU 2.0
*/
public abstract boolean useDaylightTime();
/**
* Queries if this time zone is in daylight saving time or will observe daylight saving time at
* any future time.
*
* <p>The default implementation in this class returns <code>true</code> if {@link
* #useDaylightTime()} or {@link #inDaylightTime(Date) inDaylightTime(new Date())} returns
* <code>true</code>.
*
* <p><strong>Note:</strong> This method was added for {@link java.util.TimeZone} compatibility
* support. The {@link java.util.TimeZone#useDaylightTime()} method only checks the last known
* rule(s), therefore it may return false even the zone observes daylight saving time currently.
* {@link java.util.TimeZone} added <code>observesDaylightTime()</code> to resolve the issue. In
* ICU, {@link #useDaylightTime()} works differently. The ICU implementation checks if the zone
* uses daylight saving time in the current calendar year. Therefore, it will never return
* <code>false</code> if daylight saving time is currently used.
*
* <p>ICU's TimeZone subclass implementations override this method to support the same behavior
* with {@link java.util.TimeZone#observesDaylightTime()}. Unlike {@link #useDaylightTime()},
* the implementation does not take past daylight saving time into account, so that this method
* may return <code>false</code> even when {@link #useDaylightTime()} returns <code>true</code>.
*
* @return <code>true</code> if this time zone is in daylight saving time or will observe
* daylight saving time at any future time.
* @see #useDaylightTime
* @stable ICU 49
*/
public boolean observesDaylightTime() {
return useDaylightTime() || inDaylightTime(new Date());
}
/**
* Queries if the given date is in daylight savings time in this time zone.
*
* @param date the given Date.
* @return true if the given date is in daylight savings time, false, otherwise.
* @stable ICU 2.0
*/
public abstract boolean inDaylightTime(Date date);
/**
* Gets the <code>TimeZone</code> for the given ID.
*
* @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles", or a custom ID
* such as "GMT-8:00". Note that the support of abbreviations, such as "PST", is for JDK
* 1.1.x compatibility only and full names should be used.
* @return the specified <code>TimeZone</code>, or a mutable clone of the UNKNOWN_ZONE if the
* given ID cannot be understood or if the given ID is "Etc/Unknown".
* @see #UNKNOWN_ZONE
* @stable ICU 2.0
*/
public static TimeZone getTimeZone(String ID) {
return getTimeZone(ID, TZ_IMPL, false);
}
/**
* Gets the <code>TimeZone</code> for the given ID. The instance of <code>TimeZone</code>
* returned by this method is immutable. Any methods mutate the instance({@link #setID(String)},
* {@link #setRawOffset(int)}) will throw <code>UnsupportedOperationException</code> upon its
* invocation.
*
* @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles", or a custom ID
* such as "GMT-8:00". Note that the support of abbreviations, such as "PST", is for JDK
* 1.1.x compatibility only and full names should be used.
* @return the specified <code>TimeZone</code>, or the UNKNOWN_ZONE if the given ID cannot be
* understood.
* @see #UNKNOWN_ZONE
* @stable ICU 49
*/
public static TimeZone getFrozenTimeZone(String ID) {
return getTimeZone(ID, TZ_IMPL, true);
}
/**
* Gets the <code>TimeZone</code> for the given ID and the timezone type.
*
* @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles", or a custom ID
* such as "GMT-8:00". Note that the support of abbreviations, such as "PST", is for JDK
* 1.1.x compatibility only and full names should be used.
* @param type Time zone type, either <code>TIMEZONE_ICU</code> or <code>TIMEZONE_JDK</code>.
* @return the specified <code>TimeZone</code>, or a mutable clone of the UNKNOWN_ZONE if the
* given ID cannot be understood or if the given ID is "Etc/Unknown".
* @see #UNKNOWN_ZONE
* @stable ICU 4.0
*/
public static TimeZone getTimeZone(String ID, int type) {
return getTimeZone(ID, type, false);
}
/**
* Gets the <code>TimeZone</code> for the given ID and the timezone type.
*
* @param id time zone ID
* @param type time zone implementation type, TIMEZONE_JDK or TIMEZONE_ICU
* @param frozen specify if the returned object can be frozen
* @return the specified <code>TimeZone</code> or UNKNOWN_ZONE if the given ID cannot be
* understood.
*/
private static TimeZone getTimeZone(String id, int type, boolean frozen) {
TimeZone result;
if (type == TIMEZONE_JDK) {
result = JavaTimeZone.createTimeZone(id);
if (result != null) {
return frozen ? result.freeze() : result;
}
result = getFrozenICUTimeZone(id, false);
} else {
result = getFrozenICUTimeZone(id, true);
}
if (result == null) {
LOGGER.fine(
"\""
+ id
+ "\" is a bogus id so timezone is falling back to Etc/Unknown(GMT).");
result = UNKNOWN_ZONE;
}
return frozen ? result : result.cloneAsThawed();
}
/**
* Returns a frozen ICU type TimeZone object given a time zone ID.
*
* @param id the time zone ID
* @param trySystem if true tries the system time zones first otherwise skip to the custom time
* zones.
* @return the frozen ICU TimeZone or null if one could not be created.
*/
static BasicTimeZone getFrozenICUTimeZone(String id, boolean trySystem) {
BasicTimeZone result = null;
if (trySystem) {
result = ZoneMeta.getSystemTimeZone(id);
}
if (result == null) {
result = ZoneMeta.getCustomTimeZone(id);
}
return result;
}
/**
* Sets the default time zone type used by <code>getTimeZone</code>.
*
* @param type time zone type, either <code>TIMEZONE_ICU</code> or <code>TIMEZONE_JDK</code>.
* @stable ICU 4.0
*/
public static synchronized void setDefaultTimeZoneType(int type) {
if (type != TIMEZONE_ICU && type != TIMEZONE_JDK) {
throw new IllegalArgumentException("Invalid timezone type");
}
TZ_IMPL = type;
}
/**
* {@icu} Returns the default time zone type currently used.
*
* @return The default time zone type, either <code>TIMEZONE_ICU</code> or <code>TIMEZONE_JDK
* </code>.
* @stable ICU 4.0
*/
public static int getDefaultTimeZoneType() {
return TZ_IMPL;
}
/**
* {@icu} Returns a set of time zone ID strings with the given filter conditions.
*
* <p><b>Note:</b>A <code>Set</code> returned by this method is immutable.
*
* @param zoneType The system time zone type.
* @param region The ISO 3166 two-letter country code or UN M.49 three-digit area code. When
* null, no filtering done by region.
* @param rawOffset An offset from GMT in milliseconds, ignoring the effect of daylight savings
* time, if any. When null, no filtering done by zone offset.
* @return an immutable set of system time zone IDs.
* @see SystemTimeZoneType
* @stable ICU 4.8
*/
public static Set<String> getAvailableIDs(
SystemTimeZoneType zoneType, String region, Integer rawOffset) {
return ZoneMeta.getAvailableIDs(zoneType, region, rawOffset);
}
/**
* Return a new String array containing all system TimeZone IDs with the given raw offset from
* GMT. These IDs may be passed to <code>get()</code> to construct the corresponding TimeZone
* object.
*
* @param rawOffset the offset in milliseconds from GMT
* @return an array of IDs for system TimeZones with the given raw offset. If there are none,
* return a zero-length array.
* @see #getAvailableIDs(SystemTimeZoneType, String, Integer)
* @stable ICU 2.0
*/
public static String[] getAvailableIDs(int rawOffset) {
Set<String> ids = getAvailableIDs(SystemTimeZoneType.ANY, null, rawOffset);
return ids.toArray(new String[0]);
}
/**
* Return a new String array containing all system TimeZone IDs associated with the given
* country. These IDs may be passed to <code>get()</code> to construct the corresponding
* TimeZone object.
*
* @param country a two-letter ISO 3166 country code, or <code>null</code> to return zones not
* associated with any country
* @return an array of IDs for system TimeZones in the given country. If there are none, return
* a zero-length array.
* @see #getAvailableIDs(SystemTimeZoneType, String, Integer)
* @stable ICU 2.0
*/
public static String[] getAvailableIDs(String country) {
Set<String> ids = getAvailableIDs(SystemTimeZoneType.ANY, country, null);
return ids.toArray(new String[0]);
}
/**
* Return a new String array containing all system TimeZone IDs. These IDs (and only these IDs)
* may be passed to <code>get()</code> to construct the corresponding TimeZone object.
*
* @return an array of all system TimeZone IDs
* @see #getAvailableIDs(SystemTimeZoneType, String, Integer)
* @stable ICU 2.0
*/
public static String[] getAvailableIDs() {
Set<String> ids = getAvailableIDs(SystemTimeZoneType.ANY, null, null);
return ids.toArray(new String[0]);
}
/**
* {@icu} Returns the number of IDs in the equivalency group that includes the given ID. An
* equivalency group contains zones that have the same GMT offset and rules.
*
* <p>The returned count includes the given ID; it is always >= 1 for valid IDs. The given ID
* must be a system time zone. If it is not, returns zero.
*
* @param id a system time zone ID
* @return the number of zones in the equivalency group containing 'id', or zero if 'id' is not
* a valid system ID
* @see #getEquivalentID
* @stable ICU 2.0
*/
public static int countEquivalentIDs(String id) {
return ZoneMeta.countEquivalentIDs(id);
}
/**
* Returns an ID in the equivalency group that includes the given ID. An equivalency group
* contains zones that have the same GMT offset and rules.
*
* <p>The given index must be in the range 0..n-1, where n is the value returned by <code>
* countEquivalentIDs(id)</code>. For some value of 'index', the returned value will be equal to
* the given id. If the given id is not a valid system time zone, or if 'index' is out of range,
* then returns an empty string.
*
* @param id a system time zone ID
* @param index a value from 0 to n-1, where n is the value returned by <code>
* countEquivalentIDs(id)</code>
* @return the ID of the index-th zone in the equivalency group containing 'id', or an empty
* string if 'id' is not a valid system ID or 'index' is out of range
* @see #countEquivalentIDs
* @stable ICU 2.0
*/
public static String getEquivalentID(String id, int index) {
return ZoneMeta.getEquivalentID(id, index);
}
/**
* If the locale contains the timezone keyword, creates a copy of that <code>TimeZone</code>.
* Otherwise, create the default <code>TimeZone</code>.
*
* @param locale a locale which may contains 'timezone' keyword/value.
* @return A <code>TimeZone</code>. Clients are responsible for deleting the <code>TimeZone
* </code> object returned.
* @internal
* @deprecated This API is ICU internal only.
*/
@Deprecated
public static TimeZone forULocaleOrDefault(ULocale locale) {
String tz = locale.getKeywordValue("timezone");
return (tz == null) ? getDefault() : getTimeZone(tz);
}
/**
* If the locale contains the timezone keyword, creates a copy of that <code>TimeZone</code>.
* Otherwise, create the default <code>TimeZone</code>.
*
* @param locale a locale which may contains 'timezone' keyword/value.
* @return A <code>TimeZone</code>. Clients are responsible for deleting the <code>TimeZone
* </code> object returned.
* @internal
* @deprecated This API is ICU internal only.
*/
@Deprecated
public static TimeZone forLocaleOrDefault(Locale locale) {
return forULocaleOrDefault(ULocale.forLocale(locale));
}
/**
* Gets the default <code>TimeZone</code> for this host. The source of the default <code>
* TimeZone</code> may vary with implementation.
*
* @return a default <code>TimeZone</code>.
* @stable ICU 2.0
*/
public static TimeZone getDefault() {
// Copy the reference to the current defaultZone,
// so it won't be affected by setDefault().
TimeZone tmpDefaultZone = defaultZone;
if (tmpDefaultZone == null) {
synchronized (java.util.TimeZone.class) {
synchronized (TimeZone.class) {
tmpDefaultZone = defaultZone;
if (tmpDefaultZone == null) {
if (TZ_IMPL == TIMEZONE_JDK) {
tmpDefaultZone = new JavaTimeZone();
} else {
java.util.TimeZone temp = java.util.TimeZone.getDefault();
tmpDefaultZone = getFrozenTimeZone(temp.getID());
}
defaultZone = tmpDefaultZone;
}
}
}
}
return tmpDefaultZone.cloneAsThawed();
}
/**
* Sets the <code>TimeZone</code> that is returned by the <code>getDefault</code> method. This
* method also sets a Java TimeZone equivalent to the input <code>tz</code> as the JVM's default
* time zone if not null. If <code>tz</code> is null, next {@link #getDefault()} method
* invocation will reset the default time zone synchronized with the JVM's default at that time.
*
* @param tz the new default time zone
* @stable ICU 2.0
*/
public static synchronized void setDefault(TimeZone tz) {
// Set default ICU time zone, used by #getDefault()
setICUDefault(tz);
if (tz != null) {
// Keep java.util.TimeZone default in sync so java.util.Date
// can interoperate with com.ibm.icu.util classes.
java.util.TimeZone jdkZone = null;
if (tz instanceof JavaTimeZone) {
jdkZone = ((JavaTimeZone) tz).unwrap();
} else if (tz instanceof com.ibm.icu.impl.OlsonTimeZone) {
// Because of the lack of APIs supporting historic
// zone offset/dst saving in JDK TimeZone,
// wrapping ICU TimeZone with JDK TimeZone will
// cause historic offset calculation in Calendar/Date.
// JDK calendar implementation calls getRawOffset() and
// getDSTSavings() when the instance of JDK TimeZone
// is not an instance of JDK internal TimeZone subclass
// (sun.util.calendar.ZoneInfo). Ticket#6459
String icuID = tz.getID();
jdkZone = java.util.TimeZone.getTimeZone(icuID);
if (!icuID.equals(jdkZone.getID())) {
// If the ID was unknown, retry with the canonicalized
// ID instead. This will ensure that JDK 1.1.x
// compatibility IDs supported by ICU (but not
// necessarily supported by the platform) work.
// Ticket#11483
icuID = getCanonicalID(icuID);
jdkZone = java.util.TimeZone.getTimeZone(icuID);
if (!icuID.equals(jdkZone.getID())) {
// JDK does not know the ID..
jdkZone = null;
}
}
}
if (jdkZone == null) {
jdkZone = TimeZoneAdapter.wrap(tz);
}
java.util.TimeZone.setDefault(jdkZone);
}
}
/**
* Sets the <code>TimeZone</code> that is returned by the <code>getDefault</code> method. If
* <code>tz</code> is null, next {@link #getDefault()} method invocation will reset the default
* time zone synchronized with the JVM's default at that time. Unlike {@link
* #setDefault(TimeZone)}, this method does not change the JVM's default time zone.
*
* @param tz the new default time zone
* @internal
* @deprecated This API is ICU internal only.
*/
@Deprecated
public static synchronized void setICUDefault(TimeZone tz) {
if (tz == null) {
defaultZone = null;
} else if (tz.isFrozen()) {
// No need to create a defensive copy
defaultZone = tz;
} else {
// Creates a defensive copy and freeze it
defaultZone = tz.clone().freeze();
}
}
/**
* Returns true if this zone has the same rule and offset as another zone. That is, if this zone
* differs only in ID, if at all. Returns false if the other zone is null.
*
* @param other the <code>TimeZone</code> object to be compared with
* @return true if the other zone is not null and is the same as this one, with the possible
* exception of the ID
* @stable ICU 2.0
*/
public boolean hasSameRules(TimeZone other) {
return other != null
&& getRawOffset() == other.getRawOffset()
&& useDaylightTime() == other.useDaylightTime();
}
/**
* Overrides clone.
*
* @stable ICU 2.0
*/
@Override
public TimeZone clone() {
if (isFrozen()) {
return this;
}
return cloneAsThawed();
}
/**
* Overrides equals.
*
* @return <code>true</code> if this object is the same as the obj argument; <code>false</code>
* otherwise.
* @stable ICU 2.0
*/
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null || getClass() != obj.getClass()) return false;
return (ID.equals(((TimeZone) obj).ID));
}
/**
* Overrides hashCode.
*
* @return a hash code value for this object.
* @stable ICU 2.0
*/
@Override
public int hashCode() {
return ID.hashCode();
}
/**
* {@icu} Returns the time zone data version currently used by ICU.
*
* @return the version string, such as "2007f"
* @throws MissingResourceException if ICU time zone resource bundle is missing or the version
* information is not available.
* @stable ICU 3.8
*/
public static String getTZDataVersion() {
// The implementation had been moved to VersionInfo.
return VersionInfo.getTZDataVersion();
}
/**
* {@icu} Returns the canonical system time zone ID or the normalized custom time zone ID for
* the given time zone ID.
*
* @param id The input time zone ID to be canonicalized.
* @return The canonical system time zone ID or the custom time zone ID in normalized format for
* the given time zone ID. When the given time zone ID is neither a known system time zone
* ID nor a valid custom time zone ID, null is returned.
* @stable ICU 4.0
*/
public static String getCanonicalID(String id) {
return getCanonicalID(id, null);
}
/**
* {@icu} Returns the canonical system time zone ID or the normalized custom time zone ID for
* the given time zone ID.
*
* @param id The input time zone ID to be canonicalized.
* @param isSystemID When non-null boolean array is specified and the given ID is a known system
* time zone ID, true is set to <code>isSystemID[0]</code>
* @return The canonical system time zone ID or the custom time zone ID in normalized format for
* the given time zone ID. When the given time zone ID is neither a known system time zone
* ID nor a valid custom time zone ID, null is returned.
* @stable ICU 4.0
*/
public static String getCanonicalID(String id, boolean[] isSystemID) {
String canonicalID = null;
boolean systemTzid = false;
if (id != null && id.length() != 0) {
if (id.equals(TimeZone.UNKNOWN_ZONE_ID)) {
// special case - Etc/Unknown is a canonical ID, but not system ID
canonicalID = TimeZone.UNKNOWN_ZONE_ID;
systemTzid = false;
} else {
canonicalID = ZoneMeta.getCanonicalCLDRID(id);
if (canonicalID != null) {
systemTzid = true;
} else {
canonicalID = ZoneMeta.getCustomID(id);
}
}
}
if (isSystemID != null) {
isSystemID[0] = systemTzid;
}
return canonicalID;
}
/**
* Returns the preferred time zone ID in the IANA database for the given time zone ID. There are
* two types of preferred IDs. The first type is the one defined in zone.tab file, such as
* "America/Los_Angeles". The second types is the one defined for zones not associated with a
* specific region, but not defined with "Link" syntax, such as "Etc/GMT+10".
*
* <p>Note: For most of system time zone IDs, this method returns an ID same as {@link
* TimeZone#getCanonicalID(String)}. {@link TimeZone#getCanonicalID(String)} is based on
* canonical time zone IDs defined in Unicode CLDR. These canonical time zone IDs in CLDR were
* based on very old version of the time zone database. In the IANA time zone database, some IDs
* were updated since then. This API returns a newer time zone ID. For example, CLDR defines
* "Asia/Calcutta" as the canonical time zone ID. This method returns "Asia/Kolkata" instead.
*
* <p>"Etc/Unknown" is a special time zone ID defined by CLDR. There are no corresponding zones
* in the IANA time zone database. when the input is "Etc/Unknown", this method returns
* "Etc/Unknown", but it really means no mappings available. Caller of this method should
* interpret "Etc/Unknown" as an error.
*
* @param id The input time zone ID.
* @return The preferred time zone ID in the IANA time zone database, or {@link
* TimeZone#UNKNOWN_ZONE_ID} if the input ID is not a system ID.
* @see #getCanonicalID(String)
* @stable ICU 74
*/
public static String getIanaID(String id) {
String ianaId = TimeZone.UNKNOWN_ZONE_ID;
if (id == null || id.length() == 0 || id.equals(TimeZone.UNKNOWN_ZONE_ID)) {
return ianaId;
}
String tmpIanaId = ZoneMeta.getIanaID(id);
if (tmpIanaId != null) {
ianaId = tmpIanaId;
}
return ianaId;
}
/**
* {@icu} Returns the region code associated with the given system time zone ID. The region code
* is either ISO 3166 2-letter country code or UN M.49 3-digit area code. When the time zone is
* not associated with a specific location, for example - "Etc/UTC", "EST5EDT", then this method
* returns "001" (UN M.49 area code for World).
*
* @param id the system time zone ID.
* @return the region code associated with the given system time zone ID.
* @throws IllegalArgumentException if <code>id</code> is not a known system ID.
* @see #getAvailableIDs(String)
* @stable ICU 4.8
*/
public static String getRegion(String id) {
String region = null;
// "Etc/Unknown" is not a system time zone ID,
// but in the zone data.
if (!id.equals(UNKNOWN_ZONE_ID)) {
region = ZoneMeta.getRegion(id);
}
if (region == null) {
// unknown id
throw new IllegalArgumentException("Unknown system zone id: " + id);
}
return region;
}
/**
* {@icu} Converts a system time zone ID to an equivalent Windows time zone ID. For example,
* Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles".
*
* <p>There are system time zones that cannot be mapped to Windows zones. When the input system
* time zone ID is unknown or unmappable to a Windows time zone, then this method returns <code>
* null</code>.
*
* <p>This implementation utilizes <a
* href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">Zone-Tzid mapping data</a>.
* The mapping data is updated time to time. To get the latest changes, please read the ICU user
* guide section <a
* href="https://unicode-org.github.io/icu/userguide/datetime/timezone#updating-the-time-zone-data">
* Updating the Time Zone Data</a>.
*
* @param id A system time zone ID
* @return A Windows time zone ID mapped from the input system time zone ID, or <code>null
* </code> when the input ID is unknown or unmappable.
* @see #getIDForWindowsID(String, String)
* @stable ICU 52
*/
public static String getWindowsID(String id) {
// canonicalize the input ID
boolean[] isSystemID = {false};
id = getCanonicalID(id, isSystemID);
if (!isSystemID[0]) {
// mapping data is only applicable to tz database IDs
return null;
}
UResourceBundle top =
UResourceBundle.getBundleInstance(
ICUData.ICU_BASE_NAME,
"windowsZones",
ICUResourceBundle.ICU_DATA_CLASS_LOADER);
UResourceBundle mapTimezones = top.get("mapTimezones");
UResourceBundleIterator resitr = mapTimezones.getIterator();
while (resitr.hasNext()) {
UResourceBundle winzone = resitr.next();
if (winzone.getType() != UResourceBundle.TABLE) {
continue;
}
UResourceBundleIterator rgitr = winzone.getIterator();
while (rgitr.hasNext()) {
UResourceBundle regionalData = rgitr.next();
if (regionalData.getType() != UResourceBundle.STRING) {
continue;
}
String[] tzids = regionalData.getString().split(" ");
for (String tzid : tzids) {
if (tzid.equals(id)) {
return winzone.getKey();
}
}
}
}
return null;
}
/**
* {@icu} Converts a Windows time zone ID to an equivalent system time zone ID for a region. For
* example, system time zone ID "America/Los_Angeles" is returned for input Windows ID "Pacific
* Standard Time" and region "US" (or <code>null</code>), "America/Vancouver" is returned for
* the same Windows ID "Pacific Standard Time" and region "CA".
*
* <p>Not all Windows time zones can be mapped to system time zones. When the input Windows time
* zone ID is unknown or unmappable to a system time zone, then this method returns <code>null
* </code>.
*
* <p>This implementation utilizes <a
* href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">Zone-Tzid mapping data</a>.
* The mapping data is updated time to time. To get the latest changes, please read the ICU user
* guide section <a
* href="https://unicode-org.github.io/icu/userguide/datetime/timezone#updating-the-time-zone-data">
* Updating the Time Zone Data</a>.
*
* @param winid A Windows time zone ID
* @param region A region code, or <code>null</code> if no regional preference.
* @return A system time zone ID mapped from the input Windows time zone ID, or <code>null
* </code> when the input ID is unknown or unmappable.
* @see #getWindowsID(String)
* @stable ICU 52
*/
public static String getIDForWindowsID(String winid, String region) {
String id = null;
UResourceBundle top =
UResourceBundle.getBundleInstance(
ICUData.ICU_BASE_NAME,
"windowsZones",
ICUResourceBundle.ICU_DATA_CLASS_LOADER);
UResourceBundle mapTimezones = top.get("mapTimezones");
try {
UResourceBundle zones = mapTimezones.get(winid);
if (region != null) {
try {
id = zones.getString(region);
if (id != null) {
// first ID delimited by space is the default one
int endIdx = id.indexOf(' ');
if (endIdx > 0) {
id = id.substring(0, endIdx);
}
}
} catch (MissingResourceException e) {
// no explicit region mapping found
}
}
if (id == null) {
id = zones.getString("001");
}
} catch (MissingResourceException e) {
// no mapping data found
}
return id;
}
// Freezable stuffs
/**
* {@inheritDoc}
*
* @stable ICU 49
*/
@Override
public boolean isFrozen() {
return false;
}
/**
* {@inheritDoc}
*
* @stable ICU 49
*/
@Override
public TimeZone freeze() {
throw new UnsupportedOperationException("Needs to be implemented by the subclass.");
}
/**
* {@inheritDoc}
*
* @stable ICU 49
*/
@Override
public TimeZone cloneAsThawed() {
try {
return (TimeZone) super.clone();
} catch (CloneNotSupportedException e) {
throw new ICUCloneNotSupportedException(e);
}
}
// =======================privates===============================
/**
* The string identifier of this <code>TimeZone</code>. This is a programmatic identifier used
* internally to look up <code>TimeZone</code> objects from the system table and also to map
* them to their localized display names. <code>ID</code> values are unique in the system table
* but may not be for dynamically created zones.
*
* @serial
*/
private String ID;
/** The default time zone, or null if not set. */
private static volatile TimeZone defaultZone = null;
/** TimeZone implementation type */
private static int TZ_IMPL = TIMEZONE_ICU;
/** TimeZone implementation type initialization */
private static final String TZIMPL_CONFIG_KEY = "com.ibm.icu.util.TimeZone.DefaultTimeZoneType";
private static final String TZIMPL_CONFIG_ICU = "ICU";
private static final String TZIMPL_CONFIG_JDK = "JDK";
static {
String type = ICUConfig.get(TZIMPL_CONFIG_KEY, TZIMPL_CONFIG_ICU);
if (type.equalsIgnoreCase(TZIMPL_CONFIG_JDK)) {
TZ_IMPL = TIMEZONE_JDK;
}
}
/*
* ConstantZone is a private TimeZone subclass dedicated for the two TimeZone class
* constants - TimeZone.GMT_ZONE and TimeZone.UNKNOWN_ZONE. Previously, these zones
* are instances of SimpleTimeZone. However, when the SimpleTimeZone constructor and
* TimeZone's static methods (such as TimeZone.getDefault()) are called from multiple
* threads at the same time, it causes a deadlock by TimeZone's static initializer
* and SimpleTimeZone's static initializer. To avoid this issue, these TimeZone
* constants (GMT/UNKNOWN) must be implemented by a class not visible from users.
* See ticket#11343.
*/
private static final class ConstantZone extends TimeZone {
private static final long serialVersionUID = 1L;
private int rawOffset;
private ConstantZone(int rawOffset, String ID) {
super(ID);
this.rawOffset = rawOffset;
}
@Override
public int getOffset(
int era, int year, int month, int day, int dayOfWeek, int milliseconds) {
return rawOffset;
}
@Override
public void setRawOffset(int offsetMillis) {
if (isFrozen()) {
throw new UnsupportedOperationException(
"Attempt to modify a frozen TimeZone instance.");
}
rawOffset = offsetMillis;
}
@Override
public int getRawOffset() {
return rawOffset;
}
@Override
public boolean useDaylightTime() {
return false;
}
@Override
public boolean inDaylightTime(Date date) {
return false;
}
private transient volatile boolean isFrozen = false;
@Override
public boolean isFrozen() {
return isFrozen;
}
@Override
public TimeZone freeze() {
isFrozen = true;
return this;
}
@Override
public TimeZone cloneAsThawed() {
ConstantZone tz = (ConstantZone) super.cloneAsThawed();
tz.isFrozen = false;
return tz;
}
}
}
// eof