java.util
Class TimeZone

java.lang.Object
  |
  +--java.util.TimeZone

All Implemented Interfaces:

Cloneable, Serializable

Direct Known Subclasses:

SimpleTimeZone

public abstract class TimeZone

extends Object

implements Serializable, 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:

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

You can use 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 you can create a custom time zone ID with the following syntax:

 GMT[+|-]hh[[:]mm]
 

For example, you might specify GMT+14:00 as a custom time zone ID. The TimeZone that is returned when you specify a custom time zone ID does not include daylight savings time.

For compatibility with JDK 1.1.x, some other three-letter time zone IDs (such as "PST", "CTT", "AST") are also supported. However, their use is deprecated 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.

Since:

JDK1.1

See Also:

Calendar, GregorianCalendar, SimpleTimeZone, Serialized Form

Field Summary

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 Summary

TimeZone()
Sole constructor.

Method Summary

Object	clone() Overrides Cloneable
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.
static TimeZone	getDefault() Gets the default TimeZone for this host.
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.
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.
abstract int	getRawOffset() Gets unmodified offset, NOT modified in case of daylight savings.
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 savings 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 time zone uses daylight savings time.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SHORT

public static final int SHORT

A style specifier for getDisplayName() indicating a short name, such as "PST."

Since:

1.2

See Also:

LONG, Constant Field Values

LONG

public static final int LONG

A style specifier for getDisplayName() indicating a long name, such as "Pacific Standard Time."

Since:

1.2

See Also:

SHORT, Constant Field Values

Constructor Detail

TimeZone

public TimeZone()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

getOffset

public 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. This is the offset to add *to* UTC to get local time.

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.

setRawOffset

public abstract void setRawOffset(int offsetMillis)

Sets the base time zone offset to GMT. This is the offset to add *to* UTC to get local time.

Parameters:

offsetMillis - the given base time zone offset to GMT.

getRawOffset

public abstract int getRawOffset()

Gets unmodified offset, NOT modified in case of daylight savings. This is the offset to add *to* UTC to get local time.

Returns:

the unmodified offset to add *to* UTC to get local time.

getID

public String getID()

Gets the ID of this time zone.

Returns:

the ID of this time zone.

setID

public void setID(String ID)

Sets the time zone ID. This does not change any other data in the time zone object.

Parameters:

ID - the new time zone ID.

getDisplayName

public final String getDisplayName()

Returns a name of this time zone 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 format GMT[+-]hh:mm.

Returns:

the human-readable name of this time zone in the default locale.

Since:

1.2

getDisplayName

public final String getDisplayName(Locale 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, then this method returns a string in the format GMT[+-]hh:mm.

Parameters:

locale - the locale in which to supply the display name.

Returns:

the human-readable name of this time zone in the given locale or in the default locale if the given locale is not recognized.

Since:

1.2

getDisplayName

public final String getDisplayName(boolean daylight,
                                   int style)

Returns a name of this time zone suitable for presentation to the user in the default locale. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Parameters:

daylight - if true, return the daylight savings name.

style - either LONG or SHORT

Returns:

the human-readable name of this time zone in the default locale.

Since:

1.2

getDisplayName

public 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. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Parameters:

daylight - if true, return the daylight savings name.

style - either LONG or SHORT

locale - the locale in which to supply the display name.

Returns:

the human-readable name of this time zone in the given locale or in the default locale if the given locale is not recognized.

Throws:

IllegalArgumentException - style is invalid.

Since:

1.2

useDaylightTime

public abstract boolean useDaylightTime()

Queries if this time zone uses daylight savings time.

Returns:

true if this time zone uses daylight savings time, false, otherwise.

inDaylightTime

public abstract boolean inDaylightTime(Date date)

Queries if the given date is in daylight savings time in this time zone.

Parameters:

date - the given Date.

Returns:

true if the given date is in daylight savings time, false, otherwise.

getTimeZone

public static TimeZone getTimeZone(String ID)

Gets the TimeZone for the given ID.

Parameters:

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.

Returns:

the specified TimeZone, or the GMT zone if the given ID cannot be understood.

getAvailableIDs

public static String[] getAvailableIDs(int rawOffset)

Gets the available IDs according to the given time zone offset.

Parameters:

rawOffset - the given time zone GMT offset.

Returns:

an array of IDs, where the time zone for that ID has the specified GMT offset. For example, "America/Phoenix" and "America/Denver" both have GMT-07:00, but differ in daylight savings behavior.

getAvailableIDs

public static String[] getAvailableIDs()

Gets all the available IDs supported.

Returns:

an array of IDs.

getDefault

public static TimeZone getDefault()

Gets the default TimeZone for this host. The source of the default TimeZone may vary with implementation.

Returns:

a default TimeZone.

setDefault

public static void setDefault(TimeZone zone)

Sets the 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.

Parameters:

zone - the new default time zone

hasSameRules

public boolean hasSameRules(TimeZone other)

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.

Parameters:

other - the TimeZone object to be compared with

Returns:

true if the other zone is not null and is the same as this one, with the possible exception of the ID

Since:

1.2

clone

public Object clone()

Overrides Cloneable

Overrides:

clone in class Object

Returns:

a clone of this instance.

See Also:

Cloneable