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 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.

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

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