public abstract class TimeZone extends Object implements Cloneable
TimeZone
represents a time zone offset, and also figures out daylight
savings.
Typically, you get a TimeZone
using getDefault
which creates a TimeZone
based on the time zone where the program
is running. For example, for a program running in Japan, getDefault
creates a TimeZone
object based on Japanese Standard Time.
You can also get a TimeZone
using getTimeZone
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 TimeZone
object with:
You can use theTimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
getAvailableIDs
method to iterate through
all the supported time zone IDs. You can then choose a
supported ID to get a TimeZone
.
If the time zone you want is not represented by one of the
supported IDs, then a custom time zone ID can be specified to
produce a TimeZone. The syntax of a custom time zone ID is:
Hours must be between 0 to 23 and Minutes must be between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten hours and ten minutes ahead of GMT, respectively.CustomID:GMT
Sign Hours:
MinutesGMT
Sign Hours MinutesGMT
Sign Hours Sign: one of+ -
Hours: Digit Digit Digit Minutes: Digit Digit Digit: one of0 1 2 3 4 5 6 7 8 9
The format is locale independent and digits must be taken from the
Basic Latin block of the Unicode standard. No daylight saving time
transition schedule can be specified with a custom time zone ID. If
the specified string doesn't match the syntax, "GMT"
is used.
When creating a TimeZone
, the specified custom time
zone ID is normalized in the following syntax:
For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".NormalizedCustomID:GMT
Sign TwoDigitHours:
Minutes Sign: one of+ -
TwoDigitHours: Digit Digit Minutes: Digit Digit Digit: one of0 1 2 3 4 5 6 7 8 9
This class is a pure subset of the java.util.TimeZone class in JDK 1.8.
The only time zone ID that is required to be supported is "GMT".
Apart from the methods and variables being subset, the semantics of the getTimeZone() method may also be subset: custom IDs such as "GMT-8:00" are not required to be supported.
Calendar
Modifier and Type | Field and Description |
---|---|
static int |
LONG
A style specifier for
getDisplayName() indicating
a long name, such as "Pacific Standard Time." |
static int |
SHORT
A style specifier for
getDisplayName() indicating
a short name, such as "PST." |
Constructor and Description |
---|
TimeZone()
Sole constructor.
|
Modifier and Type | Method and Description |
---|---|
Object |
clone()
Creates a copy of this
TimeZone . |
static String[] |
getAvailableIDs()
Gets all the available IDs supported.
|
static String[] |
getAvailableIDs(int rawOffset)
Gets the available IDs according to the given time zone offset in milliseconds.
|
static TimeZone |
getDefault()
Gets the default
TimeZone for this host. |
String |
getDisplayName()
Returns a long standard time name of this
TimeZone suitable for
presentation to the user in the default locale. |
String |
getDisplayName(boolean daylight,
int style)
Returns a name in the specified
style of this TimeZone
suitable for presentation to the user in the default locale. |
int |
getDSTSavings()
Returns the amount of time to be added to local standard time
to get local wall clock time.
|
String |
getID()
Gets the ID of this time zone.
|
abstract 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.
|
int |
getOffset(long date)
Returns the offset of this time zone from UTC at the specified
date.
|
abstract int |
getRawOffset()
Returns the amount of time in milliseconds to add to UTC to get
standard time in this time zone.
|
static TimeZone |
getTimeZone(String ID)
Gets the
TimeZone for the given ID. |
boolean |
hasSameRules(TimeZone other)
Returns true if this zone has the same rule and offset as another zone.
|
abstract boolean |
inDaylightTime(Date date)
Queries if the given
date is in Daylight Saving Time in
this time zone. |
static void |
setDefault(TimeZone zone)
Sets the
TimeZone that is
returned by the getDefault method. |
void |
setID(String ID)
Sets the time zone ID.
|
abstract void |
setRawOffset(int offsetMillis)
Sets the base time zone offset to GMT.
|
abstract boolean |
useDaylightTime()
Queries if this
TimeZone uses Daylight Saving Time. |
public static final int LONG
getDisplayName()
indicating
a long name, such as "Pacific Standard Time."SHORT
,
Constant Field Valuespublic static final int SHORT
getDisplayName()
indicating
a short name, such as "PST."LONG
,
Constant Field Valuespublic TimeZone()
public Object clone()
TimeZone
.public static String[] getAvailableIDs()
public static String[] getAvailableIDs(int rawOffset)
rawOffset
- the given time zone GMT offset in milliseconds.getRawOffset()
public static TimeZone getDefault()
TimeZone
for this host.
The source of the default TimeZone
may vary with implementation.TimeZone
.setDefault(java.util.TimeZone)
public final String getDisplayName()
TimeZone
suitable for
presentation to the user in the default locale.
This method returns the long name, not including daylight savings.
If the display name is not available for the locale,
then this method returns a string in the
normalized custom ID format.public final String getDisplayName(boolean daylight, int style)
style
of this TimeZone
suitable for presentation to the user in the default locale. If the
specified daylight
is true
, a Daylight Saving Time name
is returned (even if this TimeZone
doesn't observe Daylight Saving
Time). Otherwise, a Standard Time name is returned.
If the display name is not available for the locale, then this
method returns a string in the
normalized custom ID format.daylight
- if true, return the daylight savings name.style
- either LONG
or SHORT
public int getDSTSavings()
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.
public String getID()
public abstract int getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds)
This method returns a historically correct offset if an
underlying TimeZone
implementation subclass
supports historical Daylight Saving Time schedule and GMT
offset changes.
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 milliseconds in day in standard
local time.Calendar.ZONE_OFFSET
,
Calendar.DST_OFFSET
public int getOffset(long date)
This method returns a historically correct offset value if an underlying TimeZone implementation subclass supports historical Daylight Saving Time schedule and GMT offset changes.
date
- the date represented in milliseconds since January 1, 1970 00:00:00 GMTCalendar.ZONE_OFFSET
,
Calendar.DST_OFFSET
public abstract int getRawOffset()
If an underlying TimeZone
implementation subclass
supports historical GMT offset changes, the method returns the
raw offset value of the current date. In Honolulu, for example,
its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
this method always returns -36000000 milliseconds (i.e., -10
hours).
Calendar.ZONE_OFFSET
public static TimeZone getTimeZone(String ID)
TimeZone
for the given ID.ID
- the ID for a TimeZone
, either an abbreviation
such as "PST", a full name such as "America/Los_Angeles", or a custom
ID such as "GMT-8:00". Note that the support of abbreviations is
for JDK 1.1.x compatibility only and full names should be used.TimeZone
, or the GMT zone if the given ID
cannot be understood.public boolean hasSameRules(TimeZone other)
other
- the TimeZone
object to be compared withpublic abstract boolean inDaylightTime(Date date)
date
is in Daylight Saving Time in
this time zone.date
- the given Date.true
if the given date is in Daylight Saving Time,
false
, otherwise.public static void setDefault(TimeZone zone)
TimeZone
that is
returned by the getDefault
method. If zone
is null, reset the default to the value it had originally when the
VM first started.zone
- the new default time zoneSecurityException
- if the security policy does not allow the operationgetDefault()
public void setID(String ID)
ID
- the new time zone ID.public abstract void setRawOffset(int offsetMillis)
If an underlying TimeZone
implementation subclass
supports historical GMT offset changes, the specified GMT
offset is set as the latest GMT offset and the difference from
the known latest GMT offset value is used to adjust all
historical GMT offset values.
offsetMillis
- the given base time zone offset to GMT.public abstract boolean useDaylightTime()
TimeZone
uses Daylight Saving Time.
If an underlyingTimeZone
implementation subclass
supports historical Daylight Saving Time schedule changes, the
method refers to the latest Daylight Saving Time schedule
information.
Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. Use of this specification is subject to license terms.