Class SimpleTimeZone

java.lang.Object
com.ibm.icu.util.TimeZone
com.ibm.icu.util.BasicTimeZone
com.ibm.icu.util.SimpleTimeZone
All Implemented Interfaces:
Freezable<TimeZone>, Serializable, Cloneable
public class SimpleTimeZone extends BasicTimeZone implements Cloneable
[icu enhancement] ICU's replacement for java.util.SimpleTimeZone. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.

SimpleTimeZone is a concrete subclass of TimeZone that represents a time zone for use with a Gregorian calendar. This class does not handle historical changes.

Use a negative value for dayOfWeekInMonth to indicate that SimpleTimeZone should count from the end of the month backwards. For example, if Daylight Savings Time starts or ends at the last Sunday in a month, use dayOfWeekInMonth = -1 along with dayOfWeek = Calendar.SUNDAY to specify the rule.

Author:
Deborah Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu
See Also:
Status:
Stable ICU 2.0.

  • Field Details

    • WALL_TIME

      public static final int WALL_TIME
      Constant for a mode of start or end time specified as local wall time.
      See Also:
      Status:
      Stable ICU 3.8.

    • STANDARD_TIME

      public static final int STANDARD_TIME
      Constant for a mode of start or end time specified as local standard time.
      See Also:
      Status:
      Stable ICU 3.8.

    • UTC_TIME

      public static final int UTC_TIME
      Constant for a mode of start or end time specified as UTC.
      See Also:
      Status:
      Stable ICU 3.8.

  • Constructor Details

    • SimpleTimeZone

      public SimpleTimeZone(int rawOffset, String ID)
      Constructs a SimpleTimeZone with the given base time zone offset from GMT and time zone ID. Timezone IDs can be obtained from TimeZone.getAvailableIDs. Normally you should use TimeZone.getDefault to construct a TimeZone.
      Parameters:
      rawOffset - The given base time zone offset to GMT.
      ID - The time zone ID which is obtained from TimeZone.getAvailableIDs.
      Status:
      Stable ICU 2.0.

    • SimpleTimeZone

      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, time to start and end the daylight time. Timezone IDs can be obtained from TimeZone.getAvailableIDs. Normally you should use TimeZone.getDefault to create a TimeZone. For a time zone that does not use daylight saving time, do not use this constructor; instead you should use SimpleTimeZone(rawOffset, ID).

      By default, this constructor specifies day-of-week-in-month rules. That is, if the startDay is 1, and the startDayOfWeek is SUNDAY, then this indicates the first Sunday in the startMonth. A startDay of -1 likewise indicates the last Sunday. However, by using negative or zero values for certain parameters, other types of rules can be specified.

      Day of month. To specify an exact day of the month, such as March 1, set startDayOfWeek to zero.

      Day of week after day of month. To specify the first day of the week occurring on or after an exact day of the month, make the day of the week negative. For example, if startDay is 5 and startDayOfWeek is -MONDAY, this indicates the first Monday on or after the 5th day of the startMonth.

      Day of week before day of month. To specify the last day of the week occurring on or before an exact day of the month, make the day of the week and the day of the month negative. For example, if startDay is -21 and startDayOfWeek is -WEDNESDAY, this indicates the last Wednesday on or before the 21st of the startMonth.

      The above examples refer to the startMonth, startDay, and startDayOfWeek; the same applies for the endMonth, endDay, and endDayOfWeek.

      Parameters:
      rawOffset - The given base time zone offset to GMT.
      ID - The time zone ID which is obtained from TimeZone.getAvailableIDs.
      startMonth - The daylight savings starting month. Month is 0-based. eg, 0 for January.
      startDay - The daylight savings starting day-of-week-in-month. Please see the member description for an example.
      startDayOfWeek - The daylight savings starting day-of-week. Please see the member description for an example.
      startTime - The daylight savings starting time in local wall time, which is standard time in this case. Please see the member description for an example.
      endMonth - The daylight savings ending month. Month is 0-based. eg, 0 for January.
      endDay - The daylight savings ending day-of-week-in-month. Please see the member description for an example.
      endDayOfWeek - The daylight savings ending day-of-week. Please see the member description for an example.
      endTime - The daylight savings ending time in local wall time, which is daylight time in this case. Please see the member description for an example.
      Throws:
      IllegalArgumentException - the month, day, dayOfWeek, or time parameters are out of range for the start or end rule
      Status:
      Stable ICU 2.0.

    • SimpleTimeZone

      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, time and its mode to start and end the daylight time. The mode specifies either WALL_TIME or STANDARD_TIME or UTC_TIME.
      Parameters:
      rawOffset - The given base time zone offset to GMT.
      ID - The time zone ID which is obtained from TimeZone.getAvailableIDs.
      startMonth - The daylight savings starting month. Month is 0-based. eg, 0 for January.
      startDay - The daylight savings starting day-of-week-in-month. Please see the member description for an example.
      startDayOfWeek - The daylight savings starting day-of-week. Please see the member description for an example.
      startTime - The daylight savings starting time in local wall time, which is standard time in this case. Please see the member description for an example.
      startTimeMode - The mode of the start time specified by startTime.
      endMonth - The daylight savings ending month. Month is 0-based. eg, 0 for January.
      endDay - The daylight savings ending day-of-week-in-month. Please see the member description for an example.
      endDayOfWeek - The daylight savings ending day-of-week. Please see the member description for an example.
      endTime - The daylight savings ending time in local wall time, which is daylight time in this case. Please see the member description for an example.
      endTimeMode - The mode of the end time specified by endTime.
      dstSavings - The amount of time in ms saved during DST.
      Throws:
      IllegalArgumentException - the month, day, dayOfWeek, or time parameters are out of range for the start or end rule
      Status:
      Stable ICU 3.8.

    • SimpleTimeZone

      public SimpleTimeZone(int rawOffset, String ID, int startMonth, int startDay, int startDayOfWeek, int startTime, int endMonth, int endDay, int endDayOfWeek, int endTime, int dstSavings)
      Constructor. This constructor is identical to the 10-argument constructor, but also takes a dstSavings parameter.
      Parameters:
      rawOffset - The given base time zone offset to GMT.
      ID - The time zone ID which is obtained from TimeZone.getAvailableIDs.
      startMonth - The daylight savings starting month. Month is 0-based. eg, 0 for January.
      startDay - The daylight savings starting day-of-week-in-month. Please see the member description for an example.
      startDayOfWeek - The daylight savings starting day-of-week. Please see the member description for an example.
      startTime - The daylight savings starting time in local wall time, which is standard time in this case. Please see the member description for an example.
      endMonth - The daylight savings ending month. Month is 0-based. eg, 0 for January.
      endDay - The daylight savings ending day-of-week-in-month. Please see the member description for an example.
      endDayOfWeek - The daylight savings ending day-of-week. Please see the member description for an example.
      endTime - The daylight savings ending time in local wall time, which is daylight time in this case. Please see the member description for an example.
      dstSavings - The amount of time in ms saved during DST.
      Throws:
      IllegalArgumentException - the month, day, dayOfWeek, or time parameters are out of range for the start or end rule
      Status:
      Stable ICU 2.0.

  • Method Details

    • setID

      public void setID(String ID)
      Sets the time zone ID. This does not change any other data in the time zone object.
      Overrides:
      setID in class TimeZone
      Parameters:
      ID - the new time zone ID.
      Status:
      Stable ICU 3.8.

    • setRawOffset

      public void setRawOffset(int offsetMillis)
      Overrides TimeZone Sets the base time zone offset to GMT. This is the offset to add "to" UTC to get local time.
      Specified by:
      setRawOffset in class TimeZone
      Parameters:
      offsetMillis - the raw offset of the time zone
      Status:
      Stable ICU 2.0.

    • getRawOffset

      public int getRawOffset()
      Overrides TimeZone Gets the GMT offset for this time zone.
      Specified by:
      getRawOffset in class TimeZone
      Returns:
      the raw offset
      Status:
      Stable ICU 2.0.

    • setStartYear

      public void setStartYear(int year)
      Sets the daylight savings starting year.
      Parameters:
      year - The daylight savings starting year.
      Status:
      Stable ICU 2.0.

    • setStartRule

      public void setStartRule(int month, int dayOfWeekInMonth, int dayOfWeek, int time)
      Sets the daylight savings starting rule. For example, Daylight Savings Time starts at the second Sunday in March, at 2 AM in standard time. Therefore, you can set the start rule by calling: setStartRule(Calendar.MARCH, 2, Calendar.SUNDAY, 2*60*60*1000);
      Parameters:
      month - The daylight savings starting month. Month is 0-based. eg, 0 for January.
      dayOfWeekInMonth - The daylight savings starting day-of-week-in-month. Please see the member description for an example.
      dayOfWeek - The daylight savings starting day-of-week. Please see the member description for an example.
      time - The daylight savings starting time in local wall time, which is standard time in this case. Please see the member description for an example.
      Throws:
      IllegalArgumentException - the month, dayOfWeekInMonth, dayOfWeek, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setStartRule

      public void setStartRule(int month, int dayOfMonth, int time)
      Sets the DST start rule to a fixed date within a month.
      Parameters:
      month - The month in which this rule occurs (0-based).
      dayOfMonth - The date in that month (1-based).
      time - The time of that day (number of millis after midnight) when DST takes effect in local wall time, which is standard time in this case.
      Throws:
      IllegalArgumentException - the month, dayOfMonth, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setStartRule

      public void setStartRule(int month, int dayOfMonth, int dayOfWeek, int time, boolean after)
      Sets the DST start rule to a weekday before or after a give date within a month, e.g., the first Monday on or after the 8th.
      Parameters:
      month - The month in which this rule occurs (0-based).
      dayOfMonth - A date within that month (1-based).
      dayOfWeek - The day of the week on which this rule occurs.
      time - The time of that day (number of millis after midnight) when DST takes effect in local wall time, which is 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 - the month, dayOfMonth, dayOfWeek, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setEndRule

      public void setEndRule(int month, int dayOfWeekInMonth, int dayOfWeek, int time)
      Sets the daylight savings ending rule. For example, if Daylight Savings Time ends at the last (-1) Sunday in October, at 2 AM in standard time, you can set the end rule by calling: setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2*60*60*1000);
      Parameters:
      month - The daylight savings ending month. Month is 0-based. eg, 0 for January.
      dayOfWeekInMonth - The daylight savings ending day-of-week-in-month. Please see the member description for an example.
      dayOfWeek - The daylight savings ending day-of-week. Please see the member description for an example.
      time - The daylight savings ending time in local wall time, which is daylight time in this case. Please see the member description for an example.
      Throws:
      IllegalArgumentException - the month, dayOfWeekInMonth, dayOfWeek, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setEndRule

      public void setEndRule(int month, int dayOfMonth, int time)
      Sets the DST end rule to a fixed date within a month.
      Parameters:
      month - The month in which this rule occurs (0-based).
      dayOfMonth - The date in that month (1-based).
      time - The time of that day (number of millis after midnight) when DST ends in local wall time, which is daylight time in this case.
      Throws:
      IllegalArgumentException - the month, dayOfMonth, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setEndRule

      public void setEndRule(int month, int dayOfMonth, int dayOfWeek, int time, boolean after)
      Sets the DST end rule to a weekday before or after a give date within a month, e.g., the first Monday on or after the 8th.
      Parameters:
      month - The month in which this rule occurs (0-based).
      dayOfMonth - A date within that month (1-based).
      dayOfWeek - The day of the week on which this rule occurs.
      time - The time of that day (number of millis after midnight) when DST ends in local wall time, which is daylight 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 - the month, dayOfMonth, dayOfWeek, or time parameters are out of range
      Status:
      Stable ICU 2.0.

    • setDSTSavings

      public void setDSTSavings(int millisSavedDuringDST)
      Sets the amount of time in ms that the clock is advanced during DST.
      Parameters:
      millisSavedDuringDST - the number of milliseconds the time is advanced with respect to standard time when the daylight savings rules are in effect. Typically one hour (+3600000). The amount could be negative, but not 0.
      Status:
      Stable ICU 2.0.

    • getDSTSavings

      public int getDSTSavings()
      Returns the amount of time in ms that the clock is advanced during DST.
      Overrides:
      getDSTSavings in class TimeZone
      Returns:
      the number of milliseconds the time is advanced with respect to standard time when the daylight savings rules are in effect. Typically one hour (3600000). The amount could be negative, but not 0.
      Status:
      Stable ICU 2.0.

    • toString

      public String toString()
      Returns a string representation of this object.
      Overrides:
      toString in class Object
      Returns:
      a string representation of this object
      Status:
      Stable ICU 2.0.

    • getOffset

      public int getOffset(int era, int year, int month, int day, int dayOfWeek, int millis)
      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.
      Specified by:
      getOffset in class TimeZone
      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 millis in day in standard local time.
      Returns:
      the offset to add to GMT to get local time.
      Status:
      Stable ICU 2.0.

    • getOffset

      @Deprecated public int getOffset(int era, int year, int month, int day, int dayOfWeek, int millis, int monthLength)
      Deprecated.
      This API is ICU internal only.
      Status:
      Internal. This API is ICU internal only.

    • getOffsetFromLocal

      public void getOffsetFromLocal(long date, BasicTimeZone.LocalOption nonExistingTimeOpt, BasicTimeZone.LocalOption duplicatedTimeOpt, int[] offsets)
      [icu] Returns time zone offsets from local wall time.
      Overrides:
      getOffsetFromLocal in class BasicTimeZone
      Status:
      Stable ICU 69.

    • useDaylightTime

      public boolean useDaylightTime()
      Overrides TimeZone Queries if this time zone uses Daylight Saving Time.
      Specified by:
      useDaylightTime in class TimeZone
      Returns:
      true if this time zone uses daylight savings time, false, otherwise.

      Note:The default implementation of ICU TimeZone uses the tz database, which supports historic rule changes, for system time zones. With the implementation, there are time zones that used daylight savings time in the past, but no longer used currently. For example, Asia/Tokyo has never used daylight savings time since 1951. Most clients would expect that this method to return false for such case. The default implementation of this method returns true when the time zone uses daylight savings time in the current (Gregorian) calendar year.

      Status:
      Stable ICU 2.0.

    • observesDaylightTime

      public boolean observesDaylightTime()
      Queries if this time zone is in daylight saving time or will observe daylight saving time at any future time.

      The default implementation in this class returns true if TimeZone.useDaylightTime() or inDaylightTime(new Date()) returns true.

      Note: This method was added for TimeZone compatibility support. The TimeZone.useDaylightTime() method only checks the last known rule(s), therefore it may return false even the zone observes daylight saving time currently. TimeZone added observesDaylightTime() to resolve the issue. In ICU, TimeZone.useDaylightTime() works differently. The ICU implementation checks if the zone uses daylight saving time in the current calendar year. Therefore, it will never return false if daylight saving time is currently used.

      ICU's TimeZone subclass implementations override this method to support the same behavior with TimeZone.observesDaylightTime(). Unlike TimeZone.useDaylightTime(), the implementation does not take past daylight saving time into account, so that this method may return false even when TimeZone.useDaylightTime() returns true.

      Overrides:
      observesDaylightTime in class TimeZone
      Returns:
      true if this time zone is in daylight saving time or will observe daylight saving time at any future time.
      See Also:
      Status:
      Stable ICU 49.

    • inDaylightTime

      public boolean inDaylightTime(Date date)
      Overrides TimeZone Queries if the give date is in Daylight Saving Time.
      Specified by:
      inDaylightTime in class TimeZone
      Parameters:
      date - the given Date.
      Returns:
      true if the given date is in daylight savings time, false, otherwise.
      Status:
      Stable ICU 2.0.

    • equals

      public boolean equals(Object obj)
      Overrides equals.
      Overrides:
      equals in class TimeZone
      Returns:
      true if obj is a SimpleTimeZone equivalent to this
      Status:
      Stable ICU 2.0.

    • hashCode

      public int hashCode()
      Overrides hashCode.
      Overrides:
      hashCode in class TimeZone
      Returns:
      a hash code value for this object.
      Status:
      Stable ICU 2.0.

    • clone

      public SimpleTimeZone clone()
      Overrides clone.
      Overrides:
      clone in class TimeZone
      Status:
      Stable ICU 2.0.

    • hasSameRules

      public boolean hasSameRules(TimeZone othr)
      Returns true if this zone has the same rules and offset as another zone.
      Overrides:
      hasSameRules in class TimeZone
      Parameters:
      othr - the TimeZone object to be compared with
      Returns:
      true if the given zone has the same rules and offset as this one
      Status:
      Stable ICU 2.0.

    • getNextTransition

      public TimeZoneTransition getNextTransition(long base, boolean inclusive)
      [icu] Returns the first time zone transition after the base time.

      Example code: 

      System.out.println("### Iterates time zone transitions in America/Los_Angeles starting 2005-01-01 and forward");

// A TimeZone instance created by getTimeZone with TIMEZONE_ICU is always a BasicTimeZone
BasicTimeZone btz = (BasicTimeZone)TimeZone.getTimeZone("America/Los_Angeles", TimeZone.TIMEZONE_ICU);

// Date format for the wall time
SimpleDateFormat wallTimeFmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z", ULocale.US);
wallTimeFmt.setTimeZone(btz);

long start = 1104537600000L;    // 2005-01-01 0:00 UTC
for (int i = 0; i < 5; i++) {   // Up to 5 transitions
    TimeZoneTransition trans = btz.getNextTransition(start, false /* not including start time */);

    // Display the transition time and offset information
    long transTime = trans.getTime();
    System.out.println(wallTimeFmt.format(new Date(transTime - 1)) + " -> " + wallTimeFmt.format(new Date(transTime)));
    System.out.println(" - Before (Offset/Save): " + trans.getFrom().getRawOffset() + "/" + trans.getFrom().getDSTSavings());
    System.out.println(" - After  (Offset/Save): " + trans.getTo().getRawOffset() + "/" + trans.getTo().getDSTSavings());

    // Update start time for next transition
    start = transTime;
}
      Specified by:
      getNextTransition in class BasicTimeZone
      Parameters:
      base - The base time.
      inclusive - Whether the base time is inclusive or not.
      Returns:
      A Date holding the first time zone transition time after the given base time, or null if no time zone transitions are available after the base time.
      Status:
      Stable ICU 3.8.

    • getPreviousTransition

      public TimeZoneTransition getPreviousTransition(long base, boolean inclusive)
      [icu] Returns the last time zone transition before the base time.

      Example code: 

      System.out.println("### Iterates time zone transitions in America/Los_Angeles starting 2010-01-01 and backward");

// A TimeZone instance created by getTimeZone with TIMEZONE_ICU is always a BasicTimeZone
BasicTimeZone btz = (BasicTimeZone)TimeZone.getTimeZone("America/Los_Angeles", TimeZone.TIMEZONE_ICU);

// Date format for the wall time
SimpleDateFormat wallTimeFmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z", ULocale.US);
wallTimeFmt.setTimeZone(btz);

long start = 1262304000000L;    // 2010-01-01 0:00 UTC
for (int i = 0; i < 5; i++) {   // Up to 5 transitions
    TimeZoneTransition trans = btz.getPreviousTransition(start, false /* not including start time */);

    // Display the transition time and offset information
    long transTime = trans.getTime();
    System.out.println(wallTimeFmt.format(new Date(transTime - 1)) + " -> " + wallTimeFmt.format(new Date(transTime)));
    System.out.println(" - Before (Offset/Save): " + trans.getFrom().getRawOffset() + "/" + trans.getFrom().getDSTSavings());
    System.out.println(" - After  (Offset/Save): " + trans.getTo().getRawOffset() + "/" + trans.getTo().getDSTSavings());

    // Update start time for next transition
    start = transTime;
}
      Specified by:
      getPreviousTransition in class BasicTimeZone
      Parameters:
      base - The base time.
      inclusive - Whether the base time is inclusive or not.
      Returns:
      A Date holding the last time zone transition time before the given base time, or null if no time zone transitions are available before the base time.
      Status:
      Stable ICU 3.8.

    • getTimeZoneRules

      public TimeZoneRule[] getTimeZoneRules()
      [icu] Returns the array of TimeZoneRule which represents the rule of this time zone object. The first element in the result array will be the InitialTimeZoneRule instance for the initial rule. The rest will be either AnnualTimeZoneRule or TimeArrayTimeZoneRule instances representing transitions.
      Specified by:
      getTimeZoneRules in class BasicTimeZone
      Returns:
      The array of TimeZoneRule which represents this time zone.
      Status:
      Stable ICU 3.8.

    • isFrozen

      public boolean isFrozen()
      Determines whether the object has been frozen or not.
      Specified by:
      isFrozen in interface Freezable<TimeZone>
      Overrides:
      isFrozen in class TimeZone
      Status:
      Stable ICU 49.

    • freeze

      public TimeZone freeze()
      Freezes the object.
      Specified by:
      freeze in interface Freezable<TimeZone>
      Overrides:
      freeze in class TimeZone
      Returns:
      the object itself.
      Status:
      Stable ICU 49.

    • cloneAsThawed

      public SimpleTimeZone cloneAsThawed()
      Provides for the clone operation. Any clone is initially unfrozen.
      Specified by:
      cloneAsThawed in interface Freezable<TimeZone>
      Overrides:
      cloneAsThawed in class TimeZone
      Status:
      Stable ICU 49.