com.groupbyinc.common.joda.time.DateTimeZone Maven / Gradle / Ivy
/*
* Copyright 2001-2014 Stephen Colebourne
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.joda.time;
import java.io.File;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
import java.util.concurrent.atomic.AtomicReference;
import org.joda.convert.FromString;
import org.joda.convert.ToString;
import org.joda.time.chrono.BaseChronology;
import org.joda.time.field.FieldUtils;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.DateTimeFormatterBuilder;
import org.joda.time.format.FormatUtils;
import org.joda.time.tz.DefaultNameProvider;
import org.joda.time.tz.FixedDateTimeZone;
import org.joda.time.tz.NameProvider;
import org.joda.time.tz.Provider;
import org.joda.time.tz.UTCProvider;
import org.joda.time.tz.ZoneInfoProvider;
/**
* DateTimeZone represents a time zone.
*
* A time zone is a system of rules to convert time from one geographic
* location to another. For example, Paris, France is one hour ahead of
* London, England. Thus when it is 10:00 in London, it is 11:00 in Paris.
*
* All time zone rules are expressed, for historical reasons, relative to
* Greenwich, London. Local time in Greenwich is referred to as Greenwich Mean
* Time (GMT). This is similar, but not precisely identical, to Universal
* Coordinated Time, or UTC. This library only uses the term UTC.
*
* Using this system, America/Los_Angeles is expressed as UTC-08:00, or UTC-07:00
* in the summer. The offset -08:00 indicates that America/Los_Angeles time is
* obtained from UTC by adding -08:00, that is, by subtracting 8 hours.
*
* The offset differs in the summer because of daylight saving time, or DST.
* The following definitions of time are generally used:
*
* - UTC - The reference time.
*
- Standard Time - The local time without a daylight saving time offset.
* For example, in Paris, standard time is UTC+01:00.
*
- Daylight Saving Time - The local time with a daylight saving time
* offset. This offset is typically one hour, but not always. It is typically
* used in most countries away from the equator. In Paris, daylight saving
* time is UTC+02:00.
*
- Wall Time - This is what a local clock on the wall reads. This will be
* either Standard Time or Daylight Saving Time depending on the time of year
* and whether the location uses Daylight Saving Time.
*
*
* Unlike the Java TimeZone class, DateTimeZone is immutable. It also only
* supports long format time zone ids. Thus EST and ECT are not accepted.
* However, the factory that accepts a TimeZone will attempt to convert from
* the old short id to a suitable long id.
*
* There are four approaches to loading time-zone data, which are tried in this order:
*
* - load the specific {@link Provider} specified by the system property
* {@code org.joda.time.DateTimeZone.Provider}.
*
- load {@link ZoneInfoProvider} using the data in the filing system folder
* pointed to by system property {@code org.joda.time.DateTimeZone.Folder}.
*
- load {@link ZoneInfoProvider} using the data in the classpath location
* {@code org/joda/time/tz/data}.
*
- load {@link UTCProvider}
*
*
* Unless you override the standard behaviour, the default if the third approach.
*
* DateTimeZone is thread-safe and immutable, and all subclasses must be as
* well.
*
* @author Brian S O'Neill
* @author Stephen Colebourne
* @since 1.0
*/
public abstract class DateTimeZone implements Serializable {
/** Serialization version. */
private static final long serialVersionUID = 5546345482340108586L;
/** The time zone for Universal Coordinated Time */
public static final DateTimeZone UTC = UTCDateTimeZone.INSTANCE;
/** Maximum offset. */
private static final int MAX_MILLIS = (86400 * 1000) - 1;
/**
* The instance that is providing time zones.
* This is lazily initialized to reduce risks of race conditions at startup.
*/
private static final AtomicReference cProvider =
new AtomicReference();
/**
* The instance that is providing time zone names.
* This is lazily initialized to reduce risks of race conditions at startup.
*/
private static final AtomicReference cNameProvider =
new AtomicReference();
/**
* The default time zone.
* This is lazily initialized to reduce risks of race conditions at startup.
*/
private static final AtomicReference cDefault =
new AtomicReference();
//-----------------------------------------------------------------------
/**
* Gets the default time zone.
*
* The default time zone is derived from the system property {@code user.timezone}.
* If that is {@code null} or is not a valid identifier, then the value of the
* JDK {@code TimeZone} default is converted. If that fails, {@code UTC} is used.
*
* NOTE: If the {@code java.util.TimeZone} default is updated after calling this
* method, then the change will not be picked up here.
*
* @return the default datetime zone object
*/
public static DateTimeZone getDefault() {
DateTimeZone zone = cDefault.get();
if (zone == null) {
try {
try {
String id = System.getProperty("user.timezone");
if (id != null) { // null check avoids stack overflow
zone = forID(id);
}
} catch (RuntimeException ex) {
// ignored
}
if (zone == null) {
zone = forTimeZone(TimeZone.getDefault());
}
} catch (IllegalArgumentException ex) {
// ignored
}
if (zone == null) {
zone = UTC;
}
if (!cDefault.compareAndSet(null, zone)) {
zone = cDefault.get();
}
}
return zone;
}
/**
* Sets the default time zone.
*
* NOTE: Calling this method does not set the {@code java.util.TimeZone} default.
*
* @param zone the default datetime zone object, must not be null
* @throws IllegalArgumentException if the zone is null
* @throws SecurityException if the application has insufficient security rights
*/
public static void setDefault(DateTimeZone zone) throws SecurityException {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new JodaTimePermission("DateTimeZone.setDefault"));
}
if (zone == null) {
throw new IllegalArgumentException("The datetime zone must not be null");
}
cDefault.set(zone);
}
//-----------------------------------------------------------------------
/**
* Gets a time zone instance for the specified time zone id.
*
* The time zone id may be one of those returned by getAvailableIDs.
* Short ids, as accepted by {@link java.util.TimeZone}, are not accepted.
* All IDs must be specified in the long format.
* The exception is UTC, which is an acceptable id.
*
* Alternatively a locale independent, fixed offset, datetime zone can
* be specified. The form [+-]hh:mm can be used.
*
* @param id the ID of the datetime zone, null means default
* @return the DateTimeZone object for the ID
* @throws IllegalArgumentException if the ID is not recognised
*/
@FromString
public static DateTimeZone forID(String id) {
if (id == null) {
return getDefault();
}
if (id.equals("UTC")) {
return DateTimeZone.UTC;
}
DateTimeZone zone = getProvider().getZone(id);
if (zone != null) {
return zone;
}
if (id.startsWith("+") || id.startsWith("-")) {
int offset = parseOffset(id);
if (offset == 0L) {
return DateTimeZone.UTC;
} else {
id = printOffset(offset);
return fixedOffsetZone(id, offset);
}
}
throw new IllegalArgumentException("The datetime zone id '" + id + "' is not recognised");
}
/**
* Gets a time zone instance for the specified offset to UTC in hours.
* This method assumes standard length hours.
*
* This factory is a convenient way of constructing zones with a fixed offset.
*
* @param hoursOffset the offset in hours from UTC, from -23 to +23
* @return the DateTimeZone object for the offset
* @throws IllegalArgumentException if the offset is too large or too small
*/
public static DateTimeZone forOffsetHours(int hoursOffset) throws IllegalArgumentException {
return forOffsetHoursMinutes(hoursOffset, 0);
}
/**
* Gets a time zone instance for the specified offset to UTC in hours and minutes.
* This method assumes 60 minutes in an hour, and standard length minutes.
*
* This factory is a convenient way of constructing zones with a fixed offset.
* The hours value must be in the range -23 to +23.
* The minutes value must be in the range -59 to +59.
* The following combinations of sign for the hour and minute are possible:
*
* Hour Minute Example Result
*
* +ve +ve (2, 15) +02:15
* +ve zero (2, 0) +02:00
* +ve -ve (2, -15) IllegalArgumentException
*
* zero +ve (0, 15) +00:15
* zero zero (0, 0) +00:00
* zero -ve (0, -15) -00:15
*
* -ve +ve (-2, 15) -02:15
* -ve zero (-2, 0) -02:00
* -ve -ve (-2, -15) -02:15
*
* Note that in versions before 2.3, the minutes had to be zero or positive.
*
* @param hoursOffset the offset in hours from UTC, from -23 to +23
* @param minutesOffset the offset in minutes from UTC, from -59 to +59
* @return the DateTimeZone object for the offset
* @throws IllegalArgumentException if any value is out of range, the minutes are negative
* when the hours are positive, or the resulting offset exceeds +/- 23:59:59.000
*/
public static DateTimeZone forOffsetHoursMinutes(int hoursOffset, int minutesOffset) throws IllegalArgumentException {
if (hoursOffset == 0 && minutesOffset == 0) {
return DateTimeZone.UTC;
}
if (hoursOffset < -23 || hoursOffset > 23) {
throw new IllegalArgumentException("Hours out of range: " + hoursOffset);
}
if (minutesOffset < -59 || minutesOffset > 59) {
throw new IllegalArgumentException("Minutes out of range: " + minutesOffset);
}
if (hoursOffset > 0 && minutesOffset < 0) {
throw new IllegalArgumentException("Positive hours must not have negative minutes: " + minutesOffset);
}
int offset = 0;
try {
int hoursInMinutes = hoursOffset * 60;
if (hoursInMinutes < 0) {
minutesOffset = hoursInMinutes - Math.abs(minutesOffset);
} else {
minutesOffset = hoursInMinutes + minutesOffset;
}
offset = FieldUtils.safeMultiply(minutesOffset, DateTimeConstants.MILLIS_PER_MINUTE);
} catch (ArithmeticException ex) {
throw new IllegalArgumentException("Offset is too large");
}
return forOffsetMillis(offset);
}
/**
* Gets a time zone instance for the specified offset to UTC in milliseconds.
*
* @param millisOffset the offset in millis from UTC, from -23:59:59.999 to +23:59:59.999
* @return the DateTimeZone object for the offset
*/
public static DateTimeZone forOffsetMillis(int millisOffset) {
if (millisOffset < -MAX_MILLIS || millisOffset > MAX_MILLIS) {
throw new IllegalArgumentException("Millis out of range: " + millisOffset);
}
String id = printOffset(millisOffset);
return fixedOffsetZone(id, millisOffset);
}
/**
* Gets a time zone instance for a JDK TimeZone.
*
* DateTimeZone only accepts a subset of the IDs from TimeZone. The
* excluded IDs are the short three letter form (except UTC). This
* method will attempt to convert between time zones created using the
* short IDs and the full version.
*
* This method is not designed to parse time zones with rules created by
* applications using SimpleTimeZone directly.
*
* @param zone the zone to convert, null means default
* @return the DateTimeZone object for the zone
* @throws IllegalArgumentException if the zone is not recognised
*/
public static DateTimeZone forTimeZone(TimeZone zone) {
if (zone == null) {
return getDefault();
}
final String id = zone.getID();
if (id == null) {
throw new IllegalArgumentException("The TimeZone id must not be null");
}
if (id.equals("UTC")) {
return DateTimeZone.UTC;
}
// Convert from old alias before consulting provider since they may differ.
DateTimeZone dtz = null;
String convId = getConvertedId(id);
Provider provider = getProvider();
if (convId != null) {
dtz = provider.getZone(convId);
}
if (dtz == null) {
dtz = provider.getZone(id);
}
if (dtz != null) {
return dtz;
}
// Support GMT+/-hh:mm formats
if (convId == null) {
convId = id;
if (convId.startsWith("GMT+") || convId.startsWith("GMT-")) {
convId = convId.substring(3);
int offset = parseOffset(convId);
if (offset == 0L) {
return DateTimeZone.UTC;
} else {
convId = printOffset(offset);
return fixedOffsetZone(convId, offset);
}
}
}
throw new IllegalArgumentException("The datetime zone id '" + id + "' is not recognised");
}
//-----------------------------------------------------------------------
/**
* Gets the zone using a fixed offset amount.
*
* @param id the zone id
* @param offset the offset in millis
* @return the zone
*/
private static DateTimeZone fixedOffsetZone(String id, int offset) {
if (offset == 0) {
return DateTimeZone.UTC;
}
return new FixedDateTimeZone(id, null, offset, offset);
}
/**
* Gets all the available IDs supported.
*
* @return an unmodifiable Set of String IDs
*/
public static Set getAvailableIDs() {
return getProvider().getAvailableIDs();
}
//-----------------------------------------------------------------------
/**
* Gets the zone provider factory.
*
* The zone provider is a pluggable instance factory that supplies the
* actual instances of DateTimeZone.
*
* @return the provider
*/
public static Provider getProvider() {
Provider provider = cProvider.get();
if (provider == null) {
provider = getDefaultProvider();
if (!cProvider.compareAndSet(null, provider)) {
provider = cProvider.get();
}
}
return provider;
}
/**
* Sets the zone provider factory.
*
* The zone provider is a pluggable instance factory that supplies the
* actual instances of DateTimeZone.
*
* @param provider provider to use, or null for default
* @throws SecurityException if you do not have the permission DateTimeZone.setProvider
* @throws IllegalArgumentException if the provider is invalid
*/
public static void setProvider(Provider provider) throws SecurityException {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new JodaTimePermission("DateTimeZone.setProvider"));
}
if (provider == null) {
provider = getDefaultProvider();
} else {
validateProvider(provider);
}
cProvider.set(provider);
}
/**
* Sets the zone provider factory without performing the security check.
*
* @param provider provider to use, or null for default
* @return the provider
* @throws IllegalArgumentException if the provider is invalid
*/
private static Provider validateProvider(Provider provider) {
Set ids = provider.getAvailableIDs();
if (ids == null || ids.size() == 0) {
throw new IllegalArgumentException("The provider doesn't have any available ids");
}
if (!ids.contains("UTC")) {
throw new IllegalArgumentException("The provider doesn't support UTC");
}
if (!UTC.equals(provider.getZone("UTC"))) {
throw new IllegalArgumentException("Invalid UTC zone provided");
}
return provider;
}
/**
* Gets the default zone provider.
*
* This tries four approaches to loading data:
*
* - loads the provider identifier by the system property
*
org.joda.time.DateTimeZone.Provider.
* - load
ZoneInfoProvider using the data in the filing system folder
* pointed to by system property org.joda.time.DateTimeZone.Folder.
* - loads
ZoneInfoProvider using the data in the classpath location
* org/joda/time/tz/data.
* - loads
UTCProvider.
*
*
* Unless you override the standard behaviour, the default if the third approach.
*
* @return the default name provider
*/
private static Provider getDefaultProvider() {
// approach 1
try {
String providerClass = System.getProperty("org.joda.time.DateTimeZone.Provider");
if (providerClass != null) {
try {
Provider provider = (Provider) Class.forName(providerClass).newInstance();
return validateProvider(provider);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
} catch (SecurityException ex) {
// ignored
}
// approach 2
try {
String dataFolder = System.getProperty("org.joda.time.DateTimeZone.Folder");
if (dataFolder != null) {
try {
Provider provider = new ZoneInfoProvider(new File(dataFolder));
return validateProvider(provider);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
} catch (SecurityException ex) {
// ignored
}
// approach 3
try {
Provider provider = new ZoneInfoProvider("org/joda/time/tz/data");
return validateProvider(provider);
} catch (Exception ex) {
ex.printStackTrace();
}
// approach 4
return new UTCProvider();
}
//-----------------------------------------------------------------------
/**
* Gets the name provider factory.
*
* The name provider is a pluggable instance factory that supplies the
* names of each DateTimeZone.
*
* @return the provider
*/
public static NameProvider getNameProvider() {
NameProvider nameProvider = cNameProvider.get();
if (nameProvider == null) {
nameProvider = getDefaultNameProvider();
if (!cNameProvider.compareAndSet(null, nameProvider)) {
nameProvider = cNameProvider.get();
}
}
return nameProvider;
}
/**
* Sets the name provider factory.
*
* The name provider is a pluggable instance factory that supplies the
* names of each DateTimeZone.
*
* @param nameProvider provider to use, or null for default
* @throws SecurityException if you do not have the permission DateTimeZone.setNameProvider
* @throws IllegalArgumentException if the provider is invalid
*/
public static void setNameProvider(NameProvider nameProvider) throws SecurityException {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new JodaTimePermission("DateTimeZone.setNameProvider"));
}
if (nameProvider == null) {
nameProvider = getDefaultNameProvider();
}
cNameProvider.set(nameProvider);
}
/**
* Gets the default name provider.
*
* Tries the system property org.joda.time.DateTimeZone.NameProvider.
* Then uses DefaultNameProvider.
*
* @return the default name provider
*/
private static NameProvider getDefaultNameProvider() {
NameProvider nameProvider = null;
try {
String providerClass = System.getProperty("org.joda.time.DateTimeZone.NameProvider");
if (providerClass != null) {
try {
nameProvider = (NameProvider) Class.forName(providerClass).newInstance();
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
} catch (SecurityException ex) {
// ignore
}
if (nameProvider == null) {
nameProvider = new DefaultNameProvider();
}
return nameProvider;
}
//-----------------------------------------------------------------------
/**
* Converts an old style id to a new style id.
*
* @param id the old style id
* @return the new style id, null if not found
*/
private static String getConvertedId(String id) {
return LazyInit.CONVERSION_MAP.get(id);
}
/**
* Parses an offset from the string.
*
* @param str the string
* @return the offset millis
*/
private static int parseOffset(String str) {
return -(int) LazyInit.OFFSET_FORMATTER.parseMillis(str);
}
/**
* Formats a timezone offset string.
*
* This method is kept separate from the formatting classes to speed and
* simplify startup and classloading.
*
* @param offset the offset in milliseconds
* @return the time zone string
*/
private static String printOffset(int offset) {
StringBuffer buf = new StringBuffer();
if (offset >= 0) {
buf.append('+');
} else {
buf.append('-');
offset = -offset;
}
int hours = offset / DateTimeConstants.MILLIS_PER_HOUR;
FormatUtils.appendPaddedInteger(buf, hours, 2);
offset -= hours * (int) DateTimeConstants.MILLIS_PER_HOUR;
int minutes = offset / DateTimeConstants.MILLIS_PER_MINUTE;
buf.append(':');
FormatUtils.appendPaddedInteger(buf, minutes, 2);
offset -= minutes * DateTimeConstants.MILLIS_PER_MINUTE;
if (offset == 0) {
return buf.toString();
}
int seconds = offset / DateTimeConstants.MILLIS_PER_SECOND;
buf.append(':');
FormatUtils.appendPaddedInteger(buf, seconds, 2);
offset -= seconds * DateTimeConstants.MILLIS_PER_SECOND;
if (offset == 0) {
return buf.toString();
}
buf.append('.');
FormatUtils.appendPaddedInteger(buf, offset, 3);
return buf.toString();
}
// Instance fields and methods
//--------------------------------------------------------------------
private final String iID;
/**
* Constructor.
*
* @param id the id to use
* @throws IllegalArgumentException if the id is null
*/
protected DateTimeZone(String id) {
if (id == null) {
throw new IllegalArgumentException("Id must not be null");
}
iID = id;
}
// Principal methods
//--------------------------------------------------------------------
/**
* Gets the ID of this datetime zone.
*
* @return the ID of this datetime zone
*/
@ToString
public final String getID() {
return iID;
}
/**
* Returns a non-localized name that is unique to this time zone. It can be
* combined with id to form a unique key for fetching localized names.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the name for
* @return name key or null if id should be used for names
*/
public abstract String getNameKey(long instant);
/**
* Gets the short name of this datetime zone suitable for display using
* the default locale.
*
* If the name is not available for the locale, then this method returns a
* string in the format [+-]hh:mm.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the name for
* @return the human-readable short name in the default locale
*/
public final String getShortName(long instant) {
return getShortName(instant, null);
}
/**
* Gets the short name of this datetime zone suitable for display using
* the specified locale.
*
* If the name is not available for the locale, then this method returns a
* string in the format [+-]hh:mm.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the name for
* @param locale the locale to get the name for
* @return the human-readable short name in the specified locale
*/
public String getShortName(long instant, Locale locale) {
if (locale == null) {
locale = Locale.getDefault();
}
String nameKey = getNameKey(instant);
if (nameKey == null) {
return iID;
}
String name;
NameProvider np = getNameProvider();
if (np instanceof DefaultNameProvider) {
name = ((DefaultNameProvider) np).getShortName(locale, iID, nameKey, isStandardOffset(instant));
} else {
name = np.getShortName(locale, iID, nameKey);
}
if (name != null) {
return name;
}
return printOffset(getOffset(instant));
}
/**
* Gets the long name of this datetime zone suitable for display using
* the default locale.
*
* If the name is not available for the locale, then this method returns a
* string in the format [+-]hh:mm.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the name for
* @return the human-readable long name in the default locale
*/
public final String getName(long instant) {
return getName(instant, null);
}
/**
* Gets the long name of this datetime zone suitable for display using
* the specified locale.
*
* If the name is not available for the locale, then this method returns a
* string in the format [+-]hh:mm.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the name for
* @param locale the locale to get the name for
* @return the human-readable long name in the specified locale
*/
public String getName(long instant, Locale locale) {
if (locale == null) {
locale = Locale.getDefault();
}
String nameKey = getNameKey(instant);
if (nameKey == null) {
return iID;
}
String name;
NameProvider np = getNameProvider();
if (np instanceof DefaultNameProvider) {
name = ((DefaultNameProvider) np).getName(locale, iID, nameKey, isStandardOffset(instant));
} else {
name = np.getName(locale, iID, nameKey);
}
if (name != null) {
return name;
}
return printOffset(getOffset(instant));
}
/**
* Gets the millisecond offset to add to UTC to get local time.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the offset for
* @return the millisecond offset to add to UTC to get local time
*/
public abstract int getOffset(long instant);
/**
* Gets the millisecond offset to add to UTC to get local time.
*
* @param instant instant to get the offset for, null means now
* @return the millisecond offset to add to UTC to get local time
*/
public final int getOffset(ReadableInstant instant) {
if (instant == null) {
return getOffset(DateTimeUtils.currentTimeMillis());
}
return getOffset(instant.getMillis());
}
/**
* Gets the standard millisecond offset to add to UTC to get local time,
* when standard time is in effect.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the offset for
* @return the millisecond offset to add to UTC to get local time
*/
public abstract int getStandardOffset(long instant);
/**
* Checks whether, at a particular instant, the offset is standard or not.
*
* This method can be used to determine whether Summer Time (DST) applies.
* As a general rule, if the offset at the specified instant is standard,
* then either Winter time applies, or there is no Summer Time. If the
* instant is not standard, then Summer Time applies.
*
* The implementation of the method is simply whether {@link #getOffset(long)}
* equals {@link #getStandardOffset(long)} at the specified instant.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z to get the offset for
* @return true if the offset at the given instant is the standard offset
* @since 1.5
*/
public boolean isStandardOffset(long instant) {
return getOffset(instant) == getStandardOffset(instant);
}
/**
* Gets the millisecond offset to subtract from local time to get UTC time.
* This offset can be used to undo adding the offset obtained by getOffset.
*
*
* millisLocal == millisUTC + getOffset(millisUTC)
* millisUTC == millisLocal - getOffsetFromLocal(millisLocal)
*
*
* NOTE: After calculating millisLocal, some error may be introduced. At
* offset transitions (due to DST or other historical changes), ranges of
* local times may map to different UTC times.
*
* For overlaps (where the local time is ambiguous), this method returns the
* offset applicable before the gap. The effect of this is that any instant
* calculated using the offset from an overlap will be in "summer" time.
*
* For gaps, this method returns the offset applicable before the gap, ie "winter" offset.
* However, the effect of this is that any instant calculated using the offset
* from a gap will be after the gap, in "summer" time.
*
* For example, consider a zone with a gap from 01:00 to 01:59:
* Input: 00:00 (before gap) Output: Offset applicable before gap DateTime: 00:00
* Input: 00:30 (before gap) Output: Offset applicable before gap DateTime: 00:30
* Input: 01:00 (in gap) Output: Offset applicable before gap DateTime: 02:00
* Input: 01:30 (in gap) Output: Offset applicable before gap DateTime: 02:30
* Input: 02:00 (after gap) Output: Offset applicable after gap DateTime: 02:00
* Input: 02:30 (after gap) Output: Offset applicable after gap DateTime: 02:30
*
* NOTE: Prior to v2.0, the DST overlap behaviour was not defined and varied by hemisphere.
* Prior to v1.5, the DST gap behaviour was also not defined.
* In v2.4, the documentation was clarified again.
*
* @param instantLocal the millisecond instant, relative to this time zone, to get the offset for
* @return the millisecond offset to subtract from local time to get UTC time
*/
public int getOffsetFromLocal(long instantLocal) {
// get the offset at instantLocal (first estimate)
final int offsetLocal = getOffset(instantLocal);
// adjust instantLocal using the estimate and recalc the offset
final long instantAdjusted = instantLocal - offsetLocal;
final int offsetAdjusted = getOffset(instantAdjusted);
// if the offsets differ, we must be near a DST boundary
if (offsetLocal != offsetAdjusted) {
// we need to ensure that time is always after the DST gap
// this happens naturally for positive offsets, but not for negative
if ((offsetLocal - offsetAdjusted) < 0) {
// if we just return offsetAdjusted then the time is pushed
// back before the transition, whereas it should be
// on or after the transition
long nextLocal = nextTransition(instantAdjusted);
if (nextLocal == (instantLocal - offsetLocal)) {
nextLocal = Long.MAX_VALUE;
}
long nextAdjusted = nextTransition(instantLocal - offsetAdjusted);
if (nextAdjusted == (instantLocal - offsetAdjusted)) {
nextAdjusted = Long.MAX_VALUE;
}
if (nextLocal != nextAdjusted) {
return offsetLocal;
}
}
} else if (offsetLocal >= 0) {
long prev = previousTransition(instantAdjusted);
if (prev < instantAdjusted) {
int offsetPrev = getOffset(prev);
int diff = offsetPrev - offsetLocal;
if (instantAdjusted - prev <= diff) {
return offsetPrev;
}
}
}
return offsetAdjusted;
}
/**
* Converts a standard UTC instant to a local instant with the same
* local time. This conversion is used before performing a calculation
* so that the calculation can be done using a simple local zone.
*
* @param instantUTC the UTC instant to convert to local
* @return the local instant with the same local time
* @throws ArithmeticException if the result overflows a long
* @since 1.5
*/
public long convertUTCToLocal(long instantUTC) {
int offset = getOffset(instantUTC);
long instantLocal = instantUTC + offset;
// If there is a sign change, but the two values have the same sign...
if ((instantUTC ^ instantLocal) < 0 && (instantUTC ^ offset) >= 0) {
throw new ArithmeticException("Adding time zone offset caused overflow");
}
return instantLocal;
}
/**
* Converts a local instant to a standard UTC instant with the same
* local time attempting to use the same offset as the original.
*
* This conversion is used after performing a calculation
* where the calculation was done using a simple local zone.
* Whenever possible, the same offset as the original offset will be used.
* This is most significant during a daylight savings overlap.
*
* @param instantLocal the local instant to convert to UTC
* @param strict whether the conversion should reject non-existent local times
* @param originalInstantUTC the original instant that the calculation is based on
* @return the UTC instant with the same local time,
* @throws ArithmeticException if the result overflows a long
* @throws IllegalArgumentException if the zone has no equivalent local time
* @since 2.0
*/
public long convertLocalToUTC(long instantLocal, boolean strict, long originalInstantUTC) {
int offsetOriginal = getOffset(originalInstantUTC);
long instantUTC = instantLocal - offsetOriginal;
int offsetLocalFromOriginal = getOffset(instantUTC);
if (offsetLocalFromOriginal == offsetOriginal) {
return instantUTC;
}
return convertLocalToUTC(instantLocal, strict);
}
/**
* Converts a local instant to a standard UTC instant with the same
* local time. This conversion is used after performing a calculation
* where the calculation was done using a simple local zone.
*
* @param instantLocal the local instant to convert to UTC
* @param strict whether the conversion should reject non-existent local times
* @return the UTC instant with the same local time,
* @throws ArithmeticException if the result overflows a long
* @throws IllegalInstantException if the zone has no equivalent local time
* @since 1.5
*/
public long convertLocalToUTC(long instantLocal, boolean strict) {
// get the offset at instantLocal (first estimate)
int offsetLocal = getOffset(instantLocal);
// adjust instantLocal using the estimate and recalc the offset
int offset = getOffset(instantLocal - offsetLocal);
// if the offsets differ, we must be near a DST boundary
if (offsetLocal != offset) {
// if strict then always check if in DST gap
// otherwise only check if zone in Western hemisphere (as the
// value of offset is already correct for Eastern hemisphere)
if (strict || offsetLocal < 0) {
// determine if we are in the DST gap
long nextLocal = nextTransition(instantLocal - offsetLocal);
if (nextLocal == (instantLocal - offsetLocal)) {
nextLocal = Long.MAX_VALUE;
}
long nextAdjusted = nextTransition(instantLocal - offset);
if (nextAdjusted == (instantLocal - offset)) {
nextAdjusted = Long.MAX_VALUE;
}
if (nextLocal != nextAdjusted) {
// yes we are in the DST gap
if (strict) {
// DST gap is not acceptable
throw new IllegalInstantException(instantLocal, getID());
} else {
// DST gap is acceptable, but for the Western hemisphere
// the offset is wrong and will result in local times
// before the cutover so use the offsetLocal instead
offset = offsetLocal;
}
}
}
}
// check for overflow
long instantUTC = instantLocal - offset;
// If there is a sign change, but the two values have different signs...
if ((instantLocal ^ instantUTC) < 0 && (instantLocal ^ offset) < 0) {
throw new ArithmeticException("Subtracting time zone offset caused overflow");
}
return instantUTC;
}
/**
* Gets the millisecond instant in another zone keeping the same local time.
*
* The conversion is performed by converting the specified UTC millis to local
* millis in this zone, then converting back to UTC millis in the new zone.
*
* @param newZone the new zone, null means default
* @param oldInstant the UTC millisecond instant to convert
* @return the UTC millisecond instant with the same local time in the new zone
*/
public long getMillisKeepLocal(DateTimeZone newZone, long oldInstant) {
if (newZone == null) {
newZone = DateTimeZone.getDefault();
}
if (newZone == this) {
return oldInstant;
}
long instantLocal = convertUTCToLocal(oldInstant);
return newZone.convertLocalToUTC(instantLocal, false, oldInstant);
}
// //-----------------------------------------------------------------------
// /**
// * Checks if the given {@link LocalDateTime} is within an overlap.
// *
// * When switching from Daylight Savings Time to standard time there is
// * typically an overlap where the same clock hour occurs twice. This
// * method identifies whether the local datetime refers to such an overlap.
// *
// * @param localDateTime the time to check, not null
// * @return true if the given datetime refers to an overlap
// */
// public boolean isLocalDateTimeOverlap(LocalDateTime localDateTime) {
// if (isFixed()) {
// return false;
// }
// long instantLocal = localDateTime.toDateTime(DateTimeZone.UTC).getMillis();
// // get the offset at instantLocal (first estimate)
// int offsetLocal = getOffset(instantLocal);
// // adjust instantLocal using the estimate and recalc the offset
// int offset = getOffset(instantLocal - offsetLocal);
// // if the offsets differ, we must be near a DST boundary
// if (offsetLocal != offset) {
// long nextLocal = nextTransition(instantLocal - offsetLocal);
// long nextAdjusted = nextTransition(instantLocal - offset);
// if (nextLocal != nextAdjusted) {
// // in DST gap
// return false;
// }
// long diff = Math.abs(offset - offsetLocal);
// DateTime dateTime = localDateTime.toDateTime(this);
// DateTime adjusted = dateTime.plus(diff);
// if (dateTime.getHourOfDay() == adjusted.getHourOfDay() &&
// dateTime.getMinuteOfHour() == adjusted.getMinuteOfHour() &&
// dateTime.getSecondOfMinute() == adjusted.getSecondOfMinute()) {
// return true;
// }
// adjusted = dateTime.minus(diff);
// if (dateTime.getHourOfDay() == adjusted.getHourOfDay() &&
// dateTime.getMinuteOfHour() == adjusted.getMinuteOfHour() &&
// dateTime.getSecondOfMinute() == adjusted.getSecondOfMinute()) {
// return true;
// }
// return false;
// }
// return false;
// }
//
//
// DateTime dateTime = null;
// try {
// dateTime = localDateTime.toDateTime(this);
// } catch (IllegalArgumentException ex) {
// return false; // it is a gap, not an overlap
// }
// long offset1 = Math.abs(getOffset(dateTime.getMillis() + 1) - getStandardOffset(dateTime.getMillis() + 1));
// long offset2 = Math.abs(getOffset(dateTime.getMillis() - 1) - getStandardOffset(dateTime.getMillis() - 1));
// long offset = Math.max(offset1, offset2);
// if (offset == 0) {
// return false;
// }
// DateTime adjusted = dateTime.plus(offset);
// if (dateTime.getHourOfDay() == adjusted.getHourOfDay() &&
// dateTime.getMinuteOfHour() == adjusted.getMinuteOfHour() &&
// dateTime.getSecondOfMinute() == adjusted.getSecondOfMinute()) {
// return true;
// }
// adjusted = dateTime.minus(offset);
// if (dateTime.getHourOfDay() == adjusted.getHourOfDay() &&
// dateTime.getMinuteOfHour() == adjusted.getMinuteOfHour() &&
// dateTime.getSecondOfMinute() == adjusted.getSecondOfMinute()) {
// return true;
// }
// return false;
// long millis = dateTime.getMillis();
// long nextTransition = nextTransition(millis);
// long previousTransition = previousTransition(millis);
// long deltaToPreviousTransition = millis - previousTransition;
// long deltaToNextTransition = nextTransition - millis;
// if (deltaToNextTransition < deltaToPreviousTransition) {
// int offset = getOffset(nextTransition);
// int standardOffset = getStandardOffset(nextTransition);
// if (Math.abs(offset - standardOffset) >= deltaToNextTransition) {
// return true;
// }
// } else {
// int offset = getOffset(previousTransition);
// int standardOffset = getStandardOffset(previousTransition);
// if (Math.abs(offset - standardOffset) >= deltaToPreviousTransition) {
// return true;
// }
// }
// return false;
// }
/**
* Checks if the given {@link LocalDateTime} is within a gap.
*
* When switching from standard time to Daylight Savings Time there is
* typically a gap where a clock hour is missing. This method identifies
* whether the local datetime refers to such a gap.
*
* @param localDateTime the time to check, not null
* @return true if the given datetime refers to a gap
* @since 1.6
*/
public boolean isLocalDateTimeGap(LocalDateTime localDateTime) {
if (isFixed()) {
return false;
}
try {
localDateTime.toDateTime(this);
return false;
} catch (IllegalInstantException ex) {
return true;
}
}
/**
* Adjusts the offset to be the earlier or later one during an overlap.
*
* @param instant the instant to adjust
* @param earlierOrLater false for earlier, true for later
* @return the adjusted instant millis
*/
public long adjustOffset(long instant, boolean earlierOrLater) {
// a bit messy, but will work in all non-pathological cases
// evaluate 3 hours before and after to work out if anything is happening
long instantBefore = instant - 3 * DateTimeConstants.MILLIS_PER_HOUR;
long instantAfter = instant + 3 * DateTimeConstants.MILLIS_PER_HOUR;
long offsetBefore = getOffset(instantBefore);
long offsetAfter = getOffset(instantAfter);
if (offsetBefore <= offsetAfter) {
return instant; // not an overlap (less than is a gap, equal is normal case)
}
// work out range of instants that have duplicate local times
long diff = offsetBefore - offsetAfter;
long transition = nextTransition(instantBefore);
long overlapStart = transition - diff;
long overlapEnd = transition + diff;
if (instant < overlapStart || instant >= overlapEnd) {
return instant; // not an overlap
}
// calculate result
long afterStart = instant - overlapStart;
if (afterStart >= diff) {
// currently in later offset
return earlierOrLater ? instant : instant - diff;
} else {
// currently in earlier offset
return earlierOrLater ? instant + diff : instant;
}
}
// System.out.println(new DateTime(transitionStart, DateTimeZone.UTC) + " " + new DateTime(transitionStart, this));
//-----------------------------------------------------------------------
/**
* Returns true if this time zone has no transitions.
*
* @return true if no transitions
*/
public abstract boolean isFixed();
/**
* Advances the given instant to where the time zone offset or name changes.
* If the instant returned is exactly the same as passed in, then
* no changes occur after the given instant.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z
* @return milliseconds from 1970-01-01T00:00:00Z
*/
public abstract long nextTransition(long instant);
/**
* Retreats the given instant to where the time zone offset or name changes.
* If the instant returned is exactly the same as passed in, then
* no changes occur before the given instant.
*
* @param instant milliseconds from 1970-01-01T00:00:00Z
* @return milliseconds from 1970-01-01T00:00:00Z
*/
public abstract long previousTransition(long instant);
// Basic methods
//--------------------------------------------------------------------
/**
* Get the datetime zone as a {@link java.util.TimeZone}.
*
* @return the closest matching TimeZone object
*/
public java.util.TimeZone toTimeZone() {
return java.util.TimeZone.getTimeZone(iID);
}
/**
* Compare this datetime zone with another.
*
* @param object the object to compare with
* @return true if equal, based on the ID and all internal rules
*/
public abstract boolean equals(Object object);
/**
* Gets a hash code compatable with equals.
*
* @return suitable hashcode
*/
public int hashCode() {
return 57 + getID().hashCode();
}
/**
* Gets the datetime zone as a string, which is simply its ID.
* @return the id of the zone
*/
public String toString() {
return getID();
}
/**
* By default, when DateTimeZones are serialized, only a "stub" object
* referring to the id is written out. When the stub is read in, it
* replaces itself with a DateTimeZone object.
* @return a stub object to go in the stream
*/
protected Object writeReplace() throws ObjectStreamException {
return new Stub(iID);
}
/**
* Used to serialize DateTimeZones by id.
*/
private static final class Stub implements Serializable {
/** Serialization lock. */
private static final long serialVersionUID = -6471952376487863581L;
/** The ID of the zone. */
private transient String iID;
/**
* Constructor.
* @param id the id of the zone
*/
Stub(String id) {
iID = id;
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeUTF(iID);
}
private void readObject(ObjectInputStream in) throws IOException {
iID = in.readUTF();
}
private Object readResolve() throws ObjectStreamException {
return forID(iID);
}
}
//-------------------------------------------------------------------------
/**
* Lazy initialization to avoid a synchronization lock.
*/
static final class LazyInit {
/** Cache of old zone IDs to new zone IDs */
static final Map CONVERSION_MAP = buildMap();
/** Time zone offset formatter. */
static final DateTimeFormatter OFFSET_FORMATTER = buildFormatter();
private static DateTimeFormatter buildFormatter() {
// Can't use a real chronology if called during class
// initialization. Offset parser doesn't need it anyhow.
Chronology chrono = new BaseChronology() {
private static final long serialVersionUID = -3128740902654445468L;
public DateTimeZone getZone() {
return null;
}
public Chronology withUTC() {
return this;
}
public Chronology withZone(DateTimeZone zone) {
return this;
}
public String toString() {
return getClass().getName();
}
};
return new DateTimeFormatterBuilder()
.appendTimeZoneOffset(null, true, 2, 4)
.toFormatter()
.withChronology(chrono);
}
private static Map buildMap() {
// Backwards compatibility with TimeZone.
Map map = new HashMap();
map.put("GMT", "UTC");
map.put("WET", "WET");
map.put("CET", "CET");
map.put("MET", "CET");
map.put("ECT", "CET");
map.put("EET", "EET");
map.put("MIT", "Pacific/Apia");
map.put("HST", "Pacific/Honolulu"); // JDK 1.1 compatible
map.put("AST", "America/Anchorage");
map.put("PST", "America/Los_Angeles");
map.put("MST", "America/Denver"); // JDK 1.1 compatible
map.put("PNT", "America/Phoenix");
map.put("CST", "America/Chicago");
map.put("EST", "America/New_York"); // JDK 1.1 compatible
map.put("IET", "America/Indiana/Indianapolis");
map.put("PRT", "America/Puerto_Rico");
map.put("CNT", "America/St_Johns");
map.put("AGT", "America/Argentina/Buenos_Aires");
map.put("BET", "America/Sao_Paulo");
map.put("ART", "Africa/Cairo");
map.put("CAT", "Africa/Harare");
map.put("EAT", "Africa/Addis_Ababa");
map.put("NET", "Asia/Yerevan");
map.put("PLT", "Asia/Karachi");
map.put("IST", "Asia/Kolkata");
map.put("BST", "Asia/Dhaka");
map.put("VST", "Asia/Ho_Chi_Minh");
map.put("CTT", "Asia/Shanghai");
map.put("JST", "Asia/Tokyo");
map.put("ACT", "Australia/Darwin");
map.put("AET", "Australia/Sydney");
map.put("SST", "Pacific/Guadalcanal");
map.put("NST", "Pacific/Auckland");
return Collections.unmodifiableMap(map);
}
}
}