Class JavaTimeZone
- java.lang.Object
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- com.ibm.icu.util.TimeZone
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- com.ibm.icu.impl.JavaTimeZone
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public class JavaTimeZone extends TimeZone
JavaTimeZone inherits com.ibm.icu.util.TimeZone and wraps java.util.TimeZone. We used to have JDKTimeZone which wrapped Java TimeZone and used it as primary TimeZone implementation until ICU4J 3.4.1. This class works exactly like JDKTimeZone and allows ICU users who use ICU4J and JDK date/time/calendar services in mix to maintain only JDK timezone rules. This TimeZone subclass is returned by the TimeZone factory method getTimeZone(String) when the default timezone type in TimeZone class is TimeZone.TIMEZONE_JDK.- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class com.ibm.icu.util.TimeZone
TimeZone.SystemTimeZoneType
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Field Summary
Fields Modifier and Type Field Description private static java.util.TreeSet<java.lang.String>
AVAILABLESET
private boolean
isFrozen
private java.util.Calendar
javacal
private java.util.TimeZone
javatz
private static java.lang.reflect.Method
mObservesDaylightTime
private static long
serialVersionUID
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Fields inherited from class com.ibm.icu.util.TimeZone
GENERIC_LOCATION, GMT_ZONE, LONG, LONG_GENERIC, LONG_GMT, SHORT, SHORT_COMMONLY_USED, SHORT_GENERIC, SHORT_GMT, TIMEZONE_ICU, TIMEZONE_JDK, UNKNOWN_ZONE, UNKNOWN_ZONE_ID
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Constructor Summary
Constructors Constructor Description JavaTimeZone()
Constructs a JavaTimeZone with the default Java TimeZoneJavaTimeZone(java.util.TimeZone jtz, java.lang.String id)
Constructs a JavaTimeZone with the specified Java TimeZone and ID.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
clone()
Overrides clone.TimeZone
cloneAsThawed()
Provides for the clone operation.static JavaTimeZone
createTimeZone(java.lang.String id)
Creates an instance of JavaTimeZone with the given timezone ID.TimeZone
freeze()
Freezes the object.int
getDSTSavings()
Returns the amount of time to be added to local standard time to get local wall clock time.int
getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds)
Gets the time zone offset, for current date, modified in case of daylight savings.void
getOffset(long date, boolean local, int[] offsets)
Returns the time zone raw and GMT offset for the given moment in time.int
getRawOffset()
Gets unmodified offset, NOT modified in case of daylight savings.int
hashCode()
Overrides hashCode.boolean
inDaylightTime(java.util.Date date)
Queries if the given date is in daylight savings time in this time zone.boolean
isFrozen()
Determines whether the object has been frozen or not.boolean
observesDaylightTime()
Queries if this time zone is in daylight saving time or will observe daylight saving time at any future time.private void
readObject(java.io.ObjectInputStream s)
void
setRawOffset(int offsetMillis)
Sets the base time zone offset to GMT.java.util.TimeZone
unwrap()
boolean
useDaylightTime()
Queries if this time zone uses daylight savings time.-
Methods inherited from class com.ibm.icu.util.TimeZone
countEquivalentIDs, equals, forLocaleOrDefault, forULocaleOrDefault, getAvailableIDs, getAvailableIDs, getAvailableIDs, getAvailableIDs, getCanonicalID, getCanonicalID, getDefault, getDefaultTimeZoneType, getDisplayName, getDisplayName, getDisplayName, getDisplayName, getDisplayName, getDisplayName, getEquivalentID, getFrozenTimeZone, getIanaID, getID, getIDForWindowsID, getOffset, getRegion, getTimeZone, getTimeZone, getTZDataVersion, getWindowsID, hasSameRules, setDefault, setDefaultTimeZoneType, setICUDefault, setID
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Field Detail
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serialVersionUID
private static final long serialVersionUID
- See Also:
- Constant Field Values
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AVAILABLESET
private static final java.util.TreeSet<java.lang.String> AVAILABLESET
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javatz
private java.util.TimeZone javatz
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javacal
private transient java.util.Calendar javacal
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mObservesDaylightTime
private static java.lang.reflect.Method mObservesDaylightTime
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isFrozen
private transient volatile boolean isFrozen
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Constructor Detail
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JavaTimeZone
public JavaTimeZone()
Constructs a JavaTimeZone with the default Java TimeZone
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JavaTimeZone
public JavaTimeZone(java.util.TimeZone jtz, java.lang.String id)
Constructs a JavaTimeZone with the specified Java TimeZone and ID.- Parameters:
jtz
- the Java TimeZoneid
- the ID of the zone. if null, the zone ID is initialized by the given Java TimeZone's ID.
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Method Detail
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createTimeZone
public static JavaTimeZone createTimeZone(java.lang.String id)
Creates an instance of JavaTimeZone with the given timezone ID.- Parameters:
id
- A timezone ID, either a system ID or a custom ID.- Returns:
- An instance of JavaTimeZone for the given ID, or null when the ID cannot be understood.
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getOffset
public int getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds)
Description copied from class:TimeZone
Gets the time zone offset, for current date, modified in case of daylight savings. This is the offset to add to UTC to get local time.- Specified by:
getOffset
in classTimeZone
- Parameters:
era
- the era of the given date.year
- the year in the given date.month
- the month in the given date. Month is 0-based. e.g., 0 for January.day
- the day-in-month of the given date.dayOfWeek
- the day-of-week of the given date.milliseconds
- the millis in day in standard local time.- Returns:
- the offset to add to GMT to get local time.
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getOffset
public void getOffset(long date, boolean local, int[] offsets)
Description copied from class:TimeZone
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().- Overrides:
getOffset
in classTimeZone
- Parameters:
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 onlocal
.local
- if true,date
is local wall time; otherwise it is in GMT time.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 torawOffset
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.
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getRawOffset
public int getRawOffset()
Description copied from class:TimeZone
Gets unmodified offset, NOT modified in case of daylight savings. This is the offset to add to UTC to get local time.- Specified by:
getRawOffset
in classTimeZone
- Returns:
- the unmodified offset to add to UTC to get local time.
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inDaylightTime
public boolean inDaylightTime(java.util.Date date)
Description copied from class:TimeZone
Queries if the given date is in daylight savings time in this time zone.- Specified by:
inDaylightTime
in classTimeZone
- Parameters:
date
- the given Date.- Returns:
- true if the given date is in daylight savings time, false, otherwise.
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setRawOffset
public void setRawOffset(int offsetMillis)
Description copied from class:TimeZone
Sets the base time zone offset to GMT. This is the offset to add to UTC to get local time.- Specified by:
setRawOffset
in classTimeZone
- Parameters:
offsetMillis
- the given base time zone offset to GMT.
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useDaylightTime
public boolean useDaylightTime()
Description copied from class:TimeZone
Queries if this time zone uses daylight savings time.- Specified by:
useDaylightTime
in classTimeZone
- Returns:
- true if this time zone uses daylight savings time,
false, otherwise.
Note: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
false
for such case. The default implementation of this method returnstrue
when the time zone uses daylight savings time in the current (Gregorian) calendar year.
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observesDaylightTime
public boolean observesDaylightTime()
Description copied from class:TimeZone
Queries if this time zone is in daylight saving time or will observe daylight saving time at any future time.The default implementation in this class returns
true
ifTimeZone.useDaylightTime()
orinDaylightTime(new Date())
returnstrue
.Note: This method was added for
TimeZone
compatibility support. TheTimeZone.useDaylightTime()
method only checks the last known rule(s), therefore it may return false even the zone observes daylight saving time currently.TimeZone
addedobservesDaylightTime()
to resolve the issue. In ICU,TimeZone.useDaylightTime()
works differently. The ICU implementation checks if the zone uses daylight saving time in the current calendar year. Therefore, it will never returnfalse
if daylight saving time is currently used.ICU's TimeZone subclass implementations override this method to support the same behavior with
TimeZone.observesDaylightTime()
. UnlikeTimeZone.useDaylightTime()
, the implementation does not take past daylight saving time into account, so that this method may returnfalse
even whenTimeZone.useDaylightTime()
returnstrue
.- Overrides:
observesDaylightTime
in classTimeZone
- Returns:
true
if this time zone is in daylight saving time or will observe daylight saving time at any future time.- See Also:
TimeZone.useDaylightTime()
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getDSTSavings
public int getDSTSavings()
Description copied from class:TimeZone
Returns the amount of time to be added to local standard time to get local wall clock time.The default implementation always returns 3600000 milliseconds (i.e., one hour) if this time zone observes Daylight Saving Time. Otherwise, 0 (zero) is returned.
If an underlying TimeZone implementation subclass supports historical Daylight Saving Time changes, this method returns the known latest daylight saving value.
- Overrides:
getDSTSavings
in classTimeZone
- Returns:
- the amount of saving time in milliseconds
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unwrap
public java.util.TimeZone unwrap()
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clone
public java.lang.Object clone()
Description copied from class:TimeZone
Overrides clone.
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hashCode
public int hashCode()
Description copied from class:TimeZone
Overrides hashCode.
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readObject
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, java.lang.ClassNotFoundException
- Throws:
java.io.IOException
java.lang.ClassNotFoundException
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isFrozen
public boolean isFrozen()
Description copied from class:TimeZone
Determines whether the object has been frozen or not.
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cloneAsThawed
public TimeZone cloneAsThawed()
Description copied from class:TimeZone
Provides for the clone operation. Any clone is initially unfrozen.- Specified by:
cloneAsThawed
in interfaceFreezable<TimeZone>
- Overrides:
cloneAsThawed
in classTimeZone
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