[Chapter 17] TimeZone

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| 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

## Description

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` |  |

## See Also

`Calendar`, `Cloneable`, `GregorianCalendar`, `Locale`, `Serializable`, `SimpleTimeZone`

StringTokenizer |  | TooManyListenersException