Chapter 17
The java.util Package

TimeZone

Name

TimeZone

Synopsis

Class Name:

java.util.TimeZone

Superclass:

java.lang.Object

Immediate Subclasses:

java.util.SimpleTimeZone

Interfaces Implemented:

java.io.Serializable, java.lang.Cloneable

Availability:

New as of JDK 1.1

The TimeZone class is an abstract class that represents a time zone offset. In addition, the class incorporates knowledge about daylight savings time. Usually, you get a TimeZone object by calling getDefault(). This method creates a TimeZone that is appropriate for the current locale. You can also call getTimeZone() to obtain a TimeZone object for a specific time zone.

Class Summary

public abstract class java.util.TimeZone extends java.lang.Object
                      implements java.io.Serializable, java.lang.Cloneable {
  // Class Methods
  public static synchronized String[] getAvailableIDs();
  public static synchronized String[] getAvailableIDs(int rawOffset);
  public static synchronized TimeZone getDefault();
  public static synchronized TimeZone getTimeZone(String ID);
  public static synchronized void setDefault(TimeZone zone);
  // Instance Methods
  public Object clone();
  public String getID();
  public abstract int getOffset(int era, int year, int month, 
                               int day, int dayOfWeek, int milliseconds);
  public abstract int getRawOffset();
  public abstract boolean inDaylightTime(Date date);
  public void setID(String ID);
  public abstract void setRawOffset(int offsetMillis);
  public abstract boolean useDaylightTime();
}

Class Methods

getAvailiableIDs

public static synchronized String[] getAvailableIDs()

Returns

An array of strings that contains the predefined time zone IDs.

Description

This method returns a list of the predefined time zone IDs. Time zones are defined for the following ID values, starting from Greenwich, England, and progressing eastward around the world:

GMT	Greenwich Mean Time
ECT	European Central Time
EET	Eastern European Time
ART	(Arabic) Egypt Standard Time
EAT	Eastern African Time
MET	Middle East Time
NET	Near East Time
PLT	Pakistan Lahore Time
IST	India Standard Time
BST	Bangladesh Standard Time
VST	Vietnam Standard Time
CTT	China Taiwan Time
JST	Japan Standard Time
ACT	Australia Central Time
AET	Australia Eastern Time
SST	Solomon Standard Time
NST	New Zealand Standard Time
MIT	Midway Islands Time
HST	Hawaii Standard Time
AST	Alaska Standard Time
PST	Pacific Standard Time
PNT	Phoenix Standard Time
MST	Mountain Standard Time
CST	Central Standard Time
EST	Eastern Standard Time
IET	Indiana Eastern Standard Time
PRT	Puerto Rico and U.S. Virgin Islands Time
CNT	Canada Newfoundland Time
AGT	Argentina Standard Time
BET	Brazil Eastern Time
CAT	Central African Time

public static synchronized String[] getAvailableIDs(int rawOffset)

Returns

An array of strings that contains the predefined time zone IDs with the given raw offset value.

Description

This method returns a list of the predefined time zone IDs that have the given raw offset value from GMT. For example, both PNT and MST have an offset of GMT-07:00.

getDefault

public static synchronized TimeZone getDefault()

Returns

A TimeZone that represents the local time zone.

Description

This method returns the default TimeZone object for the local system.

getTimeZone

public static synchronized TimeZone getTimeZone(String ID)

Parameters

ID: The ID of a time zone.

Returns

A TimeZone that represents the time zone with the given ID.

Description

This method returns the TimeZone object that corresponds to the time zone with the given ID.

setDefault

public static synchronized void setDefault(TimeZone zone)

Parameters

zone: The new default time zone.

Description

This method sets the TimeZone that is returned by getDefault().

Instance Methods

clone

public Object clone()

Returns

A copy of this TimeZone.

Overrides

Object.clone()

Description

This method creates a copy of this TimeZone and returns it.

getID

public String getID()

Returns

The ID of this TimeZone.

Description

This method returns the ID string of this TimeZone.

getOffset

 public abstract int getOffset(int era, int year, int month, int day, int dayOfWeek, int millis)

Parameters

era

The era.

year

The year.

month

The month.

day

The day.

dayOfWeek

The day of the week.

millis

The time of day in milliseconds.

Returns

An offset from GMT, in milliseconds.

Description

This method calculates an offset from GMT for the given date for this TimeZone. In other words, the offset takes daylight savings time into account. The return value should be added to GMT to get local time.

getRawOffset

public abstract int getRawOffset()

Returns

An offset from GMT, in milliseconds.

Description

This method returns the raw offset from GMT for this TimeZone. In other words, the offset does not take daylight savings time into account.

inDaylightTime

public abstract boolean isDaylightTime(Date date)

Parameters

date: The date to be tested.

Returns

true if the given date is between the start and end of daylight savings time for this TimeZone; false otherwise.

Description

This method returns a boolean value that indicates if the given date is in daylight savings time for this TimeZone.

setID

public void setID(String ID)

Parameters

ID: The new time zone ID.

Description

This method sets the ID of this TimeZone.

setRawOffset

public abstract void setRawOffset(int offsetMillis)

Parameters

offsetMillis: The new raw offset from GMT, in milliseconds.

Description

This method is used to set the raw offset value for this TimeZone.

useDaylightTime

public abstract boolean useDaylightTime()

Returns

true if this TimeZone uses daylight savings time; false otherwise.

Description

This method returns a boolean value that indicates whether or not this TimeZone uses daylight savings time.

Inherited Methods

Method	Inherited From	Method	Inherited From
`finalize()`	`Object`	`getClass()`	`Object`
`hashCode()`	`Object`	`notify()`	`Object`
`notifyAll()`	`Object`	`toString()`	`Object`
`wait()`	`Object`	`wait(long)`	`Object`
`wait(long, int)`	`Object`