TimeZone class

TimeZone represents a time zone offset, and daylight savings.

You get a TimeZone using getDefault(). getDefault() creates a TimeZone based on the time zone where the program is running. You can also get a TimeZone using getTimeZone along with a time zone ID.

You can get a U.S. Pacific Time TimeZone object with:


TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");

You can use the 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:


     CustomID:
             GMT Sign Hours : Minutes
             GMT Sign Hours Minutes
             GMT Sign Hours
     Sign: one of
             + -
     Hours:
             Digit
             Digit Digit
     Minutes:
             Digit Digit
     Digit: one of
             0 1 2 3 4 5 6 7 8 9

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.

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:


     NormalizedCustomID:
             GMT Sign TwoDigitHours : Minutes
     Sign: one of
             + -
     TwoDigitHours:
             Digit Digit
     Minutes:
             Digit Digit
     Digit: one of
             0 1 2 3 4 5 6 7 8 9

For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".

Display Name formatter

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

TimeZone(): constructor.

Create TimeZone

static TimeZone getDefault(): Gets the default TimeZone for this host.
static TimeZone getTimeZone(String ID): Gets the TimeZone for the given ID.

Get availablve timezone ids

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.

Get display name for a timezone

String getDisplayName(): Returns a name of this time zone suitable for presentation to the user in the default locale.
String getDisplayName(boolean daylight, int style): Returns a name of this time zone suitable for presentation to the user in the default locale.
String getDisplayName(boolean daylight, int style, Locale locale): Returns a name of this time zone suitable for presentation to the user in the specified locale.
String getDisplayName(Locale locale): Returns a name of this time zone suitable for presentation to the user in the specified locale.

Get daylight saving

int getDSTSavings(): Returns the amount of time to be added to local standard time to get local wall clock time.
abstract boolean inDaylightTime(Date date): Queries if the given date is in daylight savings time in this time zone.
abstract boolean useDaylightTime(): Queries if this time zone uses daylight savings time.

Change the 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.

Get timezone id

String getID(): Gets the ID of this time zone.

Get timezone offset

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.

Compare two timezones

boolean hasSameRules(TimeZone other): Returns true if this zone has the same rule and offset as another zone.

Revised from Open JDK source code

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