SimpleTimeZone

public class SimpleTimeZone extends TimeZone

SimpleTimeZone is a concrete subclass of TimeZone that represents a time zone for use with a Gregorian calendar. The class holds an offset from GMT, called raw offset, and start and end rules for a daylight saving time schedule. Since it only holds single values for each, it cannot handle historical changes in the offset from GMT and the daylight saving schedule, except that the setStartYear method can specify the year when the daylight saving time schedule starts in effect.

To construct a SimpleTimeZone with a daylight saving time schedule, the schedule can be described with a set of rules, start-rule and end-rule. A day when daylight saving time starts or ends is specified by a combination of month, day-of-month, and day-of-week values. The month value is represented by a Calendar MONTH field value, such as Calendar.MARCH. The day-of-week value is represented by a Calendar DAY_OF_WEEK value, such as SUNDAY. The meanings of value combinations are as follows.

• Exact day of month
  To specify an exact day of month, set the month and day-of-month to an exact value, and day-of-week to zero. For example, to specify March 1, set the month to MARCH, day-of-month to 1, and day-of-week to 0.
• Day of week on or after day of month
  To specify a day of week on or after an exact day of month, set the month to an exact month value, day-of-month to the day on or after which the rule is applied, and day-of-week to a negative DAY_OF_WEEK field value. For example, to specify the second Sunday of April, set month to APRIL, day-of-month to 8, and day-of-week to -SUNDAY.
• Day of week on or before day of month
  To specify a day of the week on or before an exact day of the month, set day-of-month and day-of-week to a negative value. For example, to specify the last Wednesday on or before the 21st of March, set month to MARCH, day-of-month is -21 and day-of-week is -WEDNESDAY.
• Last day-of-week of month
  To specify, the last day-of-week of the month, set day-of-week to a DAY_OF_WEEK value and day-of-month to -1. For example, to specify the last Sunday of October, set month to OCTOBER, day-of-week to SUNDAY and day-of-month to -1.

The time of the day at which daylight saving time starts or ends is specified by a millisecond value within the day. There are three kinds of modes to specify the time: WALL_TIME, STANDARD_TIME and UTC_TIME. For example, if daylight saving time ends at 2:00 am in the wall clock time, it can be specified by 7200000 milliseconds in the WALL_TIME mode. In this case, the wall clock time for an end-rule means the same thing as the daylight time.

The following are examples of parameters for constructing time zone objects.

      // Base GMT offset: -8:00
      // DST starts:      at 2:00am in standard time
      //                  on the first Sunday in April
      // DST ends:        at 2:00am in daylight time
      //                  on the last Sunday in October
      // Save:            1 hour
      SimpleTimeZone(-28800000,
                     "America/Los_Angeles",
                     Calendar.APRIL, 1, -Calendar.SUNDAY,
                     7200000,
                     Calendar.OCTOBER, -1, Calendar.SUNDAY,
                     7200000,
                     3600000)

      // Base GMT offset: +1:00
      // DST starts:      at 1:00am in UTC time
      //                  on the last Sunday in March
      // DST ends:        at 1:00am in UTC time
      //                  on the last Sunday in October
      // Save:            1 hour
      SimpleTimeZone(3600000,
                     "Europe/Paris",
                     Calendar.MARCH, -1, Calendar.SUNDAY,
                     3600000, SimpleTimeZone.UTC_TIME,
                     Calendar.OCTOBER, -1, Calendar.SUNDAY,
                     3600000, SimpleTimeZone.UTC_TIME,
                     3600000)
 

These parameter rules are also applicable to the set rule methods, such as setStartRule.

See Also

• Calendar
• GregorianCalendar
• TimeZone

Constant Summary

int	STANDARD_TIME	Constant for a mode of start or end time specified as standard time.
int	UTC_TIME	Constant for a mode of start or end time specified as UTC.
int	WALL_TIME	Constant for a mode of start or end time specified as wall clock time.

Inherited Constant Summary

From class java.util.TimeZone

int	LONG	A style specifier for getDisplayName() indicating a long name, such as "Pacific Standard Time."
int	SHORT	A style specifier for getDisplayName() indicating a short name, such as "PST."

Public Constructor Summary

	SimpleTimeZone(int rawOffset, String ID) Constructs a SimpleTimeZone with the given base time zone offset from GMT and time zone ID with no daylight saving time schedule.
	SimpleTimeZone(int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int endMonth, int endDay, int endDayOfWeek, int endTime) Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time.
	SimpleTimeZone(int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int endMonth, int endDay, int endDayOfWeek, int endTime, int dstSavings) Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time.
	SimpleTimeZone(int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int startTimeMode, int endMonth, int endDay, int endDayOfWeek, int endTime, int endTimeMode, int dstSavings) Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time.

Public Method Summary

Object	clone() Returns a clone of this SimpleTimeZone instance.
boolean	equals(Object obj) Compares the equality of two SimpleTimeZone objects.
int	getDSTSavings() Returns the amount of time in milliseconds that the clock is advanced during daylight saving time.
int	getOffset(long date) Returns the offset of this time zone from UTC at the given time.
int	getOffset(int era, int year, int month, int day, int dayOfWeek, int millis) Returns the difference in milliseconds between local time and UTC, taking into account both the raw offset and the effect of daylight saving, for the specified date and time.
int	getRawOffset() Gets the GMT offset for this time zone.
boolean	hasSameRules(TimeZone other) Returns true if this zone has the same rules and offset as another zone.
synchronized int	hashCode() Generates the hash code for the SimpleDateFormat object.
boolean	inDaylightTime(Date date) Queries if the given date is in daylight saving time.
boolean	observesDaylightTime() Returns true if this SimpleTimeZone observes Daylight Saving Time.
void	setDSTSavings(int millisSavedDuringDST) Sets the amount of time in milliseconds that the clock is advanced during daylight saving time.
void	setEndRule(int endMonth, int endDay, int endDayOfWeek, int endTime, boolean after) Sets the daylight saving time end rule to a weekday before or after the given date within a month, e.g., the first Monday on or after the 8th.
void	setEndRule(int endMonth, int endDay, int endDayOfWeek, int endTime) Sets the daylight saving time end rule.
void	setEndRule(int endMonth, int endDay, int endTime) Sets the daylight saving time end rule to a fixed date within a month.
void	setRawOffset(int offsetMillis) Sets the base time zone offset to GMT.
void	setStartRule(int startMonth, int startDay, int startDayOfWeek, int startTime) Sets the daylight saving time start rule.
void	setStartRule(int startMonth, int startDay, int startTime) Sets the daylight saving time start rule to a fixed date within a month.
void	setStartRule(int startMonth, int startDay, int startDayOfWeek, int startTime, boolean after) Sets the daylight saving time start rule to a weekday before or after the given date within a month, e.g., the first Monday on or after the 8th.
void	setStartYear(int year) Sets the daylight saving time starting year.
String	toString() Returns a string representation of this time zone.
boolean	useDaylightTime() Queries if this time zone uses daylight saving time.

Inherited Method Summary

From class java.util.TimeZone

Object	clone() Creates a copy of this TimeZone.
synchronized static String[]	getAvailableIDs() Gets all the available IDs supported.
synchronized static String[]	getAvailableIDs(int rawOffset) Gets the available IDs according to the given time zone offset in milliseconds.
int	getDSTSavings() Returns the amount of time to be added to local standard time to get local wall clock time.
static TimeZone	getDefault() Gets the default TimeZone for this host.
String	getDisplayName(boolean daylightTime, int style, Locale locale) Returns the short or long name of this time zone with either standard or daylight time, as written in locale.
final String	getDisplayName(Locale locale) Returns a long standard time name of this TimeZone suitable for presentation to the user in the specified locale.
final 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.
final String	getDisplayName() Returns a long standard time name of this TimeZone suitable for presentation to the user in the default locale.
String	getID() Gets the ID of this time zone.
int	getOffset(long date) Returns the offset of this time zone from UTC at the specified date.
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() Returns the amount of time in milliseconds to add to UTC to get standard time in this time zone.
synchronized 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.
boolean	observesDaylightTime() Returns true if this TimeZone is currently in Daylight Saving Time, or if a transition from Standard Time to Daylight Saving Time occurs at any future time.
synchronized static void	setDefault(TimeZone timeZone) 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.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Constants

public static final int STANDARD_TIME

Constant for a mode of start or end time specified as standard time.

Constant Value: 1

public static final int UTC_TIME

Constant for a mode of start or end time specified as UTC. European Union rules are specified as UTC time, for example.

Constant Value: 2

public static final int WALL_TIME

Constant for a mode of start or end time specified as wall clock time. Wall clock time is standard time for the onset rule, and daylight time for the end rule.

Constant Value: 0

Public Constructors

public SimpleTimeZone (int rawOffset, String ID)

Constructs a SimpleTimeZone with the given base time zone offset from GMT and time zone ID with no daylight saving time schedule.

Parameters

rawOffset	The base time zone offset in milliseconds to GMT.
ID	The time zone name that is given to this instance.

public SimpleTimeZone (int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int endMonth, int endDay, int endDayOfWeek, int endTime)

Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time. Both startTime and endTime are specified to be represented in the wall clock time. The amount of daylight saving is assumed to be 3600000 milliseconds (i.e., one hour). This constructor is equivalent to:

     SimpleTimeZone(rawOffset,
                    ID,
                    startMonth,
                    startDay,
                    startDayOfWeek,
                    startTime,
                    SimpleTimeZone.WALL_TIME,
                    endMonth,
                    endDay,
                    endDayOfWeek,
                    endTime,
                    SimpleTimeZone.WALL_TIME,
                    3600000)
 

Parameters

rawOffset	The given base time zone offset from GMT.
ID	The time zone ID which is given to this object.
startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts. See the class description for the special cases of this parameter.
startDayOfWeek	The daylight saving time starting day-of-week. See the class description for the special cases of this parameter.
startTime	The daylight saving time starting time in local wall clock time (in milliseconds within the day), which is local standard time in this case.
endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends. See the class description for the special cases of this parameter.
endDayOfWeek	The daylight saving time ending day-of-week. See the class description for the special cases of this parameter.
endTime	The daylight saving ending time in local wall clock time, (in milliseconds within the day) which is local daylight time in this case.

Throws

IllegalArgumentException	if the month, day, dayOfWeek, or time parameters are out of range for the start or end rule

public SimpleTimeZone (int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int endMonth, int endDay, int endDayOfWeek, int endTime, int dstSavings)

Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time. Both startTime and endTime are assumed to be represented in the wall clock time. This constructor is equivalent to:

     SimpleTimeZone(rawOffset,
                    ID,
                    startMonth,
                    startDay,
                    startDayOfWeek,
                    startTime,
                    SimpleTimeZone.WALL_TIME,
                    endMonth,
                    endDay,
                    endDayOfWeek,
                    endTime,
                    SimpleTimeZone.WALL_TIME,
                    dstSavings)
 

Parameters

rawOffset	The given base time zone offset from GMT.
ID	The time zone ID which is given to this object.
startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts. See the class description for the special cases of this parameter.
startDayOfWeek	The daylight saving time starting day-of-week. See the class description for the special cases of this parameter.
startTime	The daylight saving time starting time in local wall clock time, which is local standard time in this case.
endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends. See the class description for the special cases of this parameter.
endDayOfWeek	The daylight saving time ending day-of-week. See the class description for the special cases of this parameter.
endTime	The daylight saving ending time in local wall clock time, which is local daylight time in this case.
dstSavings	The amount of time in milliseconds saved during daylight saving time.

Throws

IllegalArgumentException	if the month, day, dayOfWeek, or time parameters are out of range for the start or end rule

public SimpleTimeZone (int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int startTimeMode, int endMonth, int endDay, int endDayOfWeek, int endTime, int endTimeMode, int dstSavings)

Constructs a SimpleTimeZone with the given base time zone offset from GMT, time zone ID, and rules for starting and ending the daylight time. This constructor takes the full set of the start and end rules parameters, including modes of startTime and endTime. The mode specifies either wall time or standard time or UTC time.

Parameters

rawOffset	The given base time zone offset from GMT.
ID	The time zone ID which is given to this object.
startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts. See the class description for the special cases of this parameter.
startDayOfWeek	The daylight saving time starting day-of-week. See the class description for the special cases of this parameter.
startTime	The daylight saving time starting time in the time mode specified by startTimeMode.
startTimeMode	The mode of the start time specified by startTime.
endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends. See the class description for the special cases of this parameter.
endDayOfWeek	The daylight saving time ending day-of-week. See the class description for the special cases of this parameter.
endTime	The daylight saving ending time in time time mode specified by endTimeMode.
endTimeMode	The mode of the end time specified by endTime
dstSavings	The amount of time in milliseconds saved during daylight saving time.

Throws

IllegalArgumentException	if the month, day, dayOfWeek, time more, or time parameters are out of range for the start or end rule, or if a time mode value is invalid.

See Also

• WALL_TIME
• STANDARD_TIME
• UTC_TIME

Public Methods

public Object clone ()

Returns a clone of this SimpleTimeZone instance.

Returns

• a clone of this instance.

public boolean equals (Object obj)

Compares the equality of two SimpleTimeZone objects.

Parameters

obj	The SimpleTimeZone object to be compared with.

Returns

• True if the given obj is the same as this SimpleTimeZone object; false otherwise.

public int getDSTSavings ()

Returns the amount of time in milliseconds that the clock is advanced during daylight saving time.

Returns

• the number of milliseconds the time is advanced with respect to standard time when the daylight saving rules are in effect, or 0 (zero) if this time zone doesn't observe daylight saving time.

See Also

• setDSTSavings(int)

public int getOffset (long date)

Returns the offset of this time zone from UTC at the given time. If daylight saving time is in effect at the given time, the offset value is adjusted with the amount of daylight saving.

Parameters

date	the time at which the time zone offset is found

Returns

• the amount of time in milliseconds to add to UTC to get local time.

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

Returns the difference in milliseconds between local time and UTC, taking into account both the raw offset and the effect of daylight saving, for the specified date and time. This method assumes that the start and end month are distinct. It also uses a default GregorianCalendar object as its underlying calendar, such as for determining leap years. Do not use the result of this method with a calendar other than a default GregorianCalendar.

Note: In general, clients should use Calendar.get(ZONE_OFFSET) + Calendar.get(DST_OFFSET) instead of calling this method.

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.
millis	The milliseconds in day in standard local time.

Returns

• The milliseconds to add to UTC to get local time.

Throws

IllegalArgumentException	the era, month, day, dayOfWeek, or millis parameters are out of range

public int getRawOffset ()

Gets the GMT offset for this time zone.

Returns

• the GMT offset value in milliseconds

See Also

• setRawOffset(int)

public boolean hasSameRules (TimeZone other)

Returns true if this zone has the same rules and offset as another zone.

Parameters

other	the TimeZone object to be compared with

Returns

• true if the given zone is a SimpleTimeZone and has the same rules and offset as this one

public synchronized int hashCode ()

Generates the hash code for the SimpleDateFormat object.

Returns

• the hash code for this object

public boolean inDaylightTime (Date date)

Queries if the given date is in daylight saving time.

Parameters

date	the given Date.

Returns

• true if daylight saving time is in effective at the given date; false otherwise.

public boolean observesDaylightTime ()

Returns true if this SimpleTimeZone observes Daylight Saving Time. This method is equivalent to useDaylightTime().

Returns

• true if this SimpleTimeZone observes Daylight Saving Time; false otherwise.

public void setDSTSavings (int millisSavedDuringDST)

Sets the amount of time in milliseconds that the clock is advanced during daylight saving time.

Parameters

millisSavedDuringDST	the number of milliseconds the time is advanced with respect to standard time when the daylight saving time rules are in effect. A positive number, typically one hour (3600000).

See Also

• getDSTSavings()

public void setEndRule (int endMonth, int endDay, int endDayOfWeek, int endTime, boolean after)

Sets the daylight saving time end rule to a weekday before or after the given date within a month, e.g., the first Monday on or after the 8th.

Parameters

endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends.
endDayOfWeek	The daylight saving time ending day-of-week.
endTime	The daylight saving ending time in local wall clock time, (in milliseconds within the day) which is local daylight time in this case.
after	If true, this rule selects the first endDayOfWeek on or after endDay. If false, this rule selects the last endDayOfWeek on or before endDay of the month.

Throws

IllegalArgumentException	the endMonth, endDay, endDayOfWeek, or endTime parameters are out of range

public void setEndRule (int endMonth, int endDay, int endDayOfWeek, int endTime)

Sets the daylight saving time end rule. For example, if daylight saving time ends on the last Sunday in October at 2 am in wall clock time, you can set the end rule by calling: setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2*60*60*1000);

Parameters

endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends. See the class description for the special cases of this parameter.
endDayOfWeek	The daylight saving time ending day-of-week. See the class description for the special cases of this parameter.
endTime	The daylight saving ending time in local wall clock time, (in milliseconds within the day) which is local daylight time in this case.

Throws

IllegalArgumentException	if the endMonth, endDay, endDayOfWeek, or endTime parameters are out of range

public void setEndRule (int endMonth, int endDay, int endTime)

Sets the daylight saving time end rule to a fixed date within a month. This method is equivalent to:

setEndRule(endMonth, endDay, 0, endTime)

Parameters

endMonth	The daylight saving time ending month. Month is a MONTH field value (0-based. e.g., 9 for October).
endDay	The day of the month on which the daylight saving time ends.
endTime	The daylight saving ending time in local wall clock time, (in milliseconds within the day) which is local daylight time in this case.

Throws

IllegalArgumentException	the endMonth, endDay, or endTime parameters are out of range

public 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.

See Also

• getRawOffset()

public void setStartRule (int startMonth, int startDay, int startDayOfWeek, int startTime)

Sets the daylight saving time start rule. For example, if daylight saving time starts on the first Sunday in April at 2 am in local wall clock time, you can set the start rule by calling:

setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2*60*60*1000);

Parameters

startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts. See the class description for the special cases of this parameter.
startDayOfWeek	The daylight saving time starting day-of-week. See the class description for the special cases of this parameter.
startTime	The daylight saving time starting time in local wall clock time, which is local standard time in this case.

Throws

IllegalArgumentException	if the startMonth, startDay, startDayOfWeek, or startTime parameters are out of range

public void setStartRule (int startMonth, int startDay, int startTime)

Sets the daylight saving time start rule to a fixed date within a month. This method is equivalent to:

setStartRule(startMonth, startDay, 0, startTime)

Parameters

startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts.
startTime	The daylight saving time starting time in local wall clock time, which is local standard time in this case. See the class description for the special cases of this parameter.

Throws

IllegalArgumentException	if the startMonth, startDayOfMonth, or startTime parameters are out of range

public void setStartRule (int startMonth, int startDay, int startDayOfWeek, int startTime, boolean after)

Sets the daylight saving time start rule to a weekday before or after the given date within a month, e.g., the first Monday on or after the 8th.

Parameters

startMonth	The daylight saving time starting month. Month is a MONTH field value (0-based. e.g., 0 for January).
startDay	The day of the month on which the daylight saving time starts.
startDayOfWeek	The daylight saving time starting day-of-week.
startTime	The daylight saving time starting time in local wall clock time, which is local standard time in this case.
after	If true, this rule selects the first dayOfWeek on or after dayOfMonth. If false, this rule selects the last dayOfWeek on or before dayOfMonth.

Throws

IllegalArgumentException	if the startMonth, startDay, startDayOfWeek, or startTime parameters are out of range

public void setStartYear (int year)

Sets the daylight saving time starting year.

Parameters

year	The daylight saving starting year.

public String toString ()

Returns a string representation of this time zone.

Returns

• a string representation of this time zone.

public boolean useDaylightTime ()

Queries if this time zone uses daylight saving time.

Returns

• true if this time zone uses daylight saving time; false otherwise.