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 {@link
* #setStartYear 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 {@link Calendar#MONTH MONTH} field
* value, such as {@link Calendar#MARCH}. The day-of-week value is
* represented by a Calendar {@link Calendar#DAY_OF_WEEK DAY_OF_WEEK} value,
* such as {@link Calendar#SUNDAY SUNDAY}. The meanings of value combinations
* are as follows.
*
*
-{@link
* Calendar#SUNDAY SUNDAY}.-{@link Calendar#WEDNESDAY WEDNESDAY}. * 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)
* setStartRule.
*
* @since 1.1
* @see Calendar
* @see GregorianCalendar
* @see TimeZone
* @author David Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu
*/
public class SimpleTimeZone extends TimeZone {
/**
* Constructs a SimpleTimeZone with the given base time zone offset from GMT
* and time zone ID with no daylight saving time schedule.
*
* @param rawOffset The base time zone offset in milliseconds to GMT.
* @param ID The time zone name that is given to this instance.
*/
public SimpleTimeZone(int rawOffset, String ID)
{
this.rawOffset = rawOffset;
setID (ID);
dstSavings = millisPerHour; // In case user sets rules later
}
/**
* 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.{@link #WALL_TIME},
* endMonth,
* endDay,
* endDayOfWeek,
* endTime,
* SimpleTimeZone.{@link #WALL_TIME},
* 3600000)
* 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.{@link #WALL_TIME},
* endMonth,
* endDay,
* endDayOfWeek,
* endTime,
* SimpleTimeZone.{@link #WALL_TIME},
* dstSavings)
* startTime and
* endTime. The mode specifies either {@link #WALL_TIME wall
* time} or {@link #STANDARD_TIME standard time} or {@link #UTC_TIME UTC
* time}.
*
* @param rawOffset The given base time zone offset from GMT.
* @param ID The time zone ID which is given to this object.
* @param startMonth The daylight saving time starting month. Month is
* a {@link Calendar#MONTH MONTH} field
* value (0-based. e.g., 0 for January).
* @param startDay The day of the month on which the daylight saving time starts.
* See the class description for the special cases of this parameter.
* @param startDayOfWeek The daylight saving time starting day-of-week.
* See the class description for the special cases of this parameter.
* @param startTime The daylight saving time starting time in the time mode
* specified by startTimeMode.
* @param startTimeMode The mode of the start time specified by startTime.
* @param endMonth The daylight saving time ending month. Month is
* a {@link Calendar#MONTH MONTH} field
* value (0-based. e.g., 9 for October).
* @param endDay The day of the month on which the daylight saving time ends.
* See the class description for the special cases of this parameter.
* @param endDayOfWeek The daylight saving time ending day-of-week.
* See the class description for the special cases of this parameter.
* @param endTime The daylight saving ending time in time time mode
* specified by endTimeMode.
* @param endTimeMode The mode of the end time specified by endTime
* @param dstSavings The amount of time in milliseconds saved during
* daylight saving time.
*
* @exception 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 #WALL_TIME
* @see #STANDARD_TIME
* @see #UTC_TIME
*
* @since 1.4
*/
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) {
setID(ID);
this.rawOffset = rawOffset;
this.startMonth = startMonth;
this.startDay = startDay;
this.startDayOfWeek = startDayOfWeek;
this.startTime = startTime;
this.startTimeMode = startTimeMode;
this.endMonth = endMonth;
this.endDay = endDay;
this.endDayOfWeek = endDayOfWeek;
this.endTime = endTime;
this.endTimeMode = endTimeMode;
this.dstSavings = dstSavings;
// this.useDaylight is set by decodeRules
decodeRules();
if (dstSavings <= 0) {
throw new IllegalArgumentException("Illegal daylight saving value: " + dstSavings);
}
}
/**
* Sets the daylight saving time starting year.
*
* @param year The daylight saving starting year.
*/
public void setStartYear(int year)
{
startYear = year;
invalidateCache();
}
/**
* 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);startMonth, startDay,
* startDayOfWeek, or startTime parameters are out of range
*/
public void setStartRule(int startMonth, int startDay, int startDayOfWeek, int startTime)
{
this.startMonth = startMonth;
this.startDay = startDay;
this.startDayOfWeek = startDayOfWeek;
this.startTime = startTime;
startTimeMode = WALL_TIME;
decodeStartRule();
invalidateCache();
}
/**
* Sets the daylight saving time start rule to a fixed date within a month.
* This method is equivalent to:
* setStartRule(startMonth, startDay, 0, startTime)startMonth,
* startDayOfMonth, or startTime parameters are out of range
* @since 1.2
*/
public void setStartRule(int startMonth, int startDay, int startTime) {
setStartRule(startMonth, startDay, 0, startTime);
}
/**
* 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.
*
* @param startMonth The daylight saving time starting month. Month is
* a {@link Calendar#MONTH MONTH} field
* value (0-based. e.g., 0 for January).
* @param startDay The day of the month on which the daylight saving time starts.
* @param startDayOfWeek The daylight saving time starting day-of-week.
* @param startTime The daylight saving time starting time in local wall clock
* time, which is local standard time in this case.
* @param 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.
* @exception IllegalArgumentException if the startMonth, startDay,
* startDayOfWeek, or startTime parameters are out of range
* @since 1.2
*/
public void setStartRule(int startMonth, int startDay, int startDayOfWeek,
int startTime, boolean after)
{
// TODO: this method doesn't check the initial values of dayOfMonth or dayOfWeek.
if (after) {
setStartRule(startMonth, startDay, -startDayOfWeek, startTime);
} else {
setStartRule(startMonth, -startDay, -startDayOfWeek, startTime);
}
}
/**
* 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);
*
* @param endMonth The daylight saving time ending month. Month is
* a {@link Calendar#MONTH MONTH} field
* value (0-based. e.g., 9 for October).
* @param endDay The day of the month on which the daylight saving time ends.
* See the class description for the special cases of this parameter.
* @param endDayOfWeek The daylight saving time ending day-of-week.
* See the class description for the special cases of this parameter.
* @param endTime The daylight saving ending time in local wall clock time,
* (in milliseconds within the day) which is local daylight
* time in this case.
* @exception IllegalArgumentException if the endMonth, endDay,
* endDayOfWeek, or endTime parameters are out of range
*/
public void setEndRule(int endMonth, int endDay, int endDayOfWeek,
int endTime)
{
this.endMonth = endMonth;
this.endDay = endDay;
this.endDayOfWeek = endDayOfWeek;
this.endTime = endTime;
this.endTimeMode = WALL_TIME;
decodeEndRule();
invalidateCache();
}
/**
* Sets the daylight saving time end rule to a fixed date within a month.
* This method is equivalent to:
* setEndRule(endMonth, endDay, 0, endTime)endMonth, endDay,
* or endTime parameters are out of range
* @since 1.2
*/
public void setEndRule(int endMonth, int endDay, int endTime)
{
setEndRule(endMonth, endDay, 0, endTime);
}
/**
* 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.
*
* @param endMonth The daylight saving time ending month. Month is
* a {@link Calendar#MONTH MONTH} field
* value (0-based. e.g., 9 for October).
* @param endDay The day of the month on which the daylight saving time ends.
* @param endDayOfWeek The daylight saving time ending day-of-week.
* @param endTime The daylight saving ending time in local wall clock time,
* (in milliseconds within the day) which is local daylight
* time in this case.
* @param 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.
* @exception IllegalArgumentException the endMonth, endDay,
* endDayOfWeek, or endTime parameters are out of range
* @since 1.2
*/
public void setEndRule(int endMonth, int endDay, int endDayOfWeek, int endTime, boolean after)
{
if (after) {
setEndRule(endMonth, endDay, -endDayOfWeek, endTime);
} else {
setEndRule(endMonth, -endDay, -endDayOfWeek, endTime);
}
}
/**
* 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.
*
* @param date the time at which the time zone offset is found
* @return the amount of time in milliseconds to add to UTC to get
* local time.
* @since 1.4
*/
public int getOffset(long date) {
return getOffsets(date, null);
}
/**
* @see TimeZone#getOffsets
*/
int getOffsets(long date, int[] offsets) {
int offset = rawOffset;
computeOffset:
if (useDaylight) {
synchronized (this) {
if (cacheStart != 0) {
if (date >= cacheStart && date < cacheEnd) {
offset += dstSavings;
break computeOffset;
}
}
}
BaseCalendar cal = date >= GregorianCalendar.DEFAULT_GREGORIAN_CUTOVER ?
gcal : (BaseCalendar) CalendarSystem.forName("julian");
BaseCalendar.Date cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);
// Get the year in local time
cal.getCalendarDate(date + rawOffset, cdate);
int year = cdate.getNormalizedYear();
if (year >= startYear) {
// Clear time elements for the transition calculations
cdate.setTimeOfDay(0, 0, 0, 0);
offset = getOffset(cal, cdate, year, date);
}
}
if (offsets != null) {
offsets[0] = rawOffset;
offsets[1] = offset - rawOffset;
}
return offset;
}
/**
* 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 {@link 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.
*
* @param era The era of the given date.
* @param year The year in the given date.
* @param month The month in the given date. Month is 0-based. e.g.,
* 0 for January.
* @param day The day-in-month of the given date.
* @param dayOfWeek The day-of-week of the given date.
* @param millis The milliseconds in day in standard local time.
* @return The milliseconds to add to UTC to get local time.
* @exception IllegalArgumentException the era,
* month, day, dayOfWeek,
* or millis parameters are out of range
*/
public int getOffset(int era, int year, int month, int day, int dayOfWeek,
int millis)
{
if (era != GregorianCalendar.AD && era != GregorianCalendar.BC) {
throw new IllegalArgumentException("Illegal era " + era);
}
int y = year;
if (era == GregorianCalendar.BC) {
// adjust y with the GregorianCalendar-style year numbering.
y = 1 - y;
}
// If the year isn't representable with the 64-bit long
// integer in milliseconds, convert the year to an
// equivalent year. This is required to pass some JCK test cases
// which are actually useless though because the specified years
// can't be supported by the Java time system.
if (y >= 292278994) {
y = 2800 + y % 2800;
} else if (y <= -292269054) {
// y %= 28 also produces an equivalent year, but positive
// year numbers would be convenient to use the UNIX cal
// command.
y = (int) CalendarUtils.mod((long) y, 28);
}
// convert year to its 1-based month value
int m = month + 1;
// First, calculate time as a Gregorian date.
BaseCalendar cal = gcal;
BaseCalendar.Date cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);
cdate.setDate(y, m, day);
long time = cal.getTime(cdate); // normalize cdate
time += millis - rawOffset; // UTC time
// If the time value represents a time before the default
// Gregorian cutover, recalculate time using the Julian
// calendar system. For the Julian calendar system, the
// normalized year numbering is ..., -2 (BCE 2), -1 (BCE 1),
// 1, 2 ... which is different from the GregorianCalendar
// style year numbering (..., -1, 0 (BCE 1), 1, 2, ...).
if (time < GregorianCalendar.DEFAULT_GREGORIAN_CUTOVER) {
cal = (BaseCalendar) CalendarSystem.forName("julian");
cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);
cdate.setNormalizedDate(y, m, day);
time = cal.getTime(cdate) + millis - rawOffset;
}
if ((cdate.getNormalizedYear() != y)
|| (cdate.getMonth() != m)
|| (cdate.getDayOfMonth() != day)
// The validation should be cdate.getDayOfWeek() ==
// dayOfWeek. However, we don't check dayOfWeek for
// compatibility.
|| (dayOfWeek < Calendar.SUNDAY || dayOfWeek > Calendar.SATURDAY)
|| (millis < 0 || millis >= (24*60*60*1000))) {
throw new IllegalArgumentException();
}
if (!useDaylight || year < startYear || era != GregorianCalendar.CE) {
return rawOffset;
}
return getOffset(cal, cdate, y, time);
}
private int getOffset(BaseCalendar cal, BaseCalendar.Date cdate, int year, long time) {
synchronized (this) {
if (cacheStart != 0) {
if (time >= cacheStart && time < cacheEnd) {
return rawOffset + dstSavings;
}
if (year == cacheYear) {
return rawOffset;
}
}
}
long start = getStart(cal, cdate, year);
long end = getEnd(cal, cdate, year);
int offset = rawOffset;
if (start <= end) {
if (time >= start && time < end) {
offset += dstSavings;
}
synchronized (this) {
cacheYear = year;
cacheStart = start;
cacheEnd = end;
}
} else {
if (time < end) {
// TODO: support Gregorian cutover. The previous year
// may be in the other calendar system.
start = getStart(cal, cdate, year - 1);
if (time >= start) {
offset += dstSavings;
}
} else if (time >= start) {
// TODO: support Gregorian cutover. The next year
// may be in the other calendar system.
end = getEnd(cal, cdate, year + 1);
if (time < end) {
offset += dstSavings;
}
}
if (start <= end) {
synchronized (this) {
// The start and end transitions are in multiple years.
cacheYear = (long) startYear - 1;
cacheStart = start;
cacheEnd = end;
}
}
}
return offset;
}
private long getStart(BaseCalendar cal, BaseCalendar.Date cdate, int year) {
int time = startTime;
if (startTimeMode != UTC_TIME) {
time -= rawOffset;
}
return getTransition(cal, cdate, startMode, year, startMonth, startDay,
startDayOfWeek, time);
}
private long getEnd(BaseCalendar cal, BaseCalendar.Date cdate, int year) {
int time = endTime;
if (endTimeMode != UTC_TIME) {
time -= rawOffset;
}
if (endTimeMode == WALL_TIME) {
time -= dstSavings;
}
return getTransition(cal, cdate, endMode, year, endMonth, endDay,
endDayOfWeek, time);
}
private long getTransition(BaseCalendar cal, BaseCalendar.Date cdate,
int mode, int year, int month, int dayOfMonth,
int dayOfWeek, int timeOfDay) {
cdate.setNormalizedYear(year);
cdate.setMonth(month + 1);
switch (mode) {
case DOM_MODE:
cdate.setDayOfMonth(dayOfMonth);
break;
case DOW_IN_MONTH_MODE:
cdate.setDayOfMonth(1);
if (dayOfMonth < 0) {
cdate.setDayOfMonth(cal.getMonthLength(cdate));
}
cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(dayOfMonth, dayOfWeek, cdate);
break;
case DOW_GE_DOM_MODE:
cdate.setDayOfMonth(dayOfMonth);
cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(1, dayOfWeek, cdate);
break;
case DOW_LE_DOM_MODE:
cdate.setDayOfMonth(dayOfMonth);
cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(-1, dayOfWeek, cdate);
break;
}
return cal.getTime(cdate) + timeOfDay;
}
/**
* Gets the GMT offset for this time zone.
* @return the GMT offset value in milliseconds
* @see #setRawOffset
*/
public int getRawOffset()
{
// The given date will be taken into account while
// we have the historical time zone data in place.
return rawOffset;
}
/**
* Sets the base time zone offset to GMT.
* This is the offset to add to UTC to get local time.
* @see #getRawOffset
*/
public void setRawOffset(int offsetMillis)
{
this.rawOffset = offsetMillis;
}
/**
* Sets the amount of time in milliseconds that the clock is advanced
* during daylight saving time.
* @param 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 #getDSTSavings
* @since 1.2
*/
public void setDSTSavings(int millisSavedDuringDST) {
if (millisSavedDuringDST <= 0) {
throw new IllegalArgumentException("Illegal daylight saving value: "
+ millisSavedDuringDST);
}
dstSavings = millisSavedDuringDST;
}
/**
* Returns the amount of time in milliseconds that the clock is
* advanced during daylight saving time.
*
* @return 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 #setDSTSavings
* @since 1.2
*/
public int getDSTSavings() {
return useDaylight ? dstSavings : 0;
}
/**
* Queries if this time zone uses daylight saving time.
* @return true if this time zone uses daylight saving time;
* false otherwise.
*/
public boolean useDaylightTime()
{
return useDaylight;
}
/**
* Returns {@code true} if this {@code SimpleTimeZone} observes
* Daylight Saving Time. This method is equivalent to {@link
* #useDaylightTime()}.
*
* @return {@code true} if this {@code SimpleTimeZone} observes
* Daylight Saving Time; {@code false} otherwise.
* @since 1.7
*/
@Override
public boolean observesDaylightTime() {
return useDaylightTime();
}
/**
* Queries if the given date is in daylight saving time.
* @return true if daylight saving time is in effective at the
* given date; false otherwise.
*/
public boolean inDaylightTime(Date date)
{
return (getOffset(date.getTime()) != rawOffset);
}
/**
* Returns a clone of this SimpleTimeZone instance.
* @return a clone of this instance.
*/
public Object clone()
{
return super.clone();
}
/**
* Generates the hash code for the SimpleDateFormat object.
* @return the hash code for this object
*/
public synchronized int hashCode()
{
return startMonth ^ startDay ^ startDayOfWeek ^ startTime ^
endMonth ^ endDay ^ endDayOfWeek ^ endTime ^ rawOffset;
}
/**
* Compares the equality of two SimpleTimeZone objects.
*
* @param obj The SimpleTimeZone object to be compared with.
* @return True if the given obj is the same as this
* SimpleTimeZone object; false otherwise.
*/
public boolean equals(Object obj)
{
if (this == obj) {
return true;
}
if (!(obj instanceof SimpleTimeZone)) {
return false;
}
SimpleTimeZone that = (SimpleTimeZone) obj;
return getID().equals(that.getID()) &&
hasSameRules(that);
}
/**
* Returns true if this zone has the same rules and offset as another zone.
* @param other the TimeZone object to be compared with
* @return true if the given zone is a SimpleTimeZone and has the
* same rules and offset as this one
* @since 1.2
*/
public boolean hasSameRules(TimeZone other) {
if (this == other) {
return true;
}
if (!(other instanceof SimpleTimeZone)) {
return false;
}
SimpleTimeZone that = (SimpleTimeZone) other;
return rawOffset == that.rawOffset &&
useDaylight == that.useDaylight &&
(!useDaylight
// Only check rules if using DST
|| (dstSavings == that.dstSavings &&
startMode == that.startMode &&
startMonth == that.startMonth &&
startDay == that.startDay &&
startDayOfWeek == that.startDayOfWeek &&
startTime == that.startTime &&
startTimeMode == that.startTimeMode &&
endMode == that.endMode &&
endMonth == that.endMonth &&
endDay == that.endDay &&
endDayOfWeek == that.endDayOfWeek &&
endTime == that.endTime &&
endTimeMode == that.endTimeMode &&
startYear == that.startYear));
}
/**
* Returns a string representation of this time zone.
* @return a string representation of this time zone.
*/
public String toString() {
return getClass().getName() +
"[id=" + getID() +
",offset=" + rawOffset +
",dstSavings=" + dstSavings +
",useDaylight=" + useDaylight +
",startYear=" + startYear +
",startMode=" + startMode +
",startMonth=" + startMonth +
",startDay=" + startDay +
",startDayOfWeek=" + startDayOfWeek +
",startTime=" + startTime +
",startTimeMode=" + startTimeMode +
",endMode=" + endMode +
",endMonth=" + endMonth +
",endDay=" + endDay +
",endDayOfWeek=" + endDayOfWeek +
",endTime=" + endTime +
",endTimeMode=" + endTimeMode + ']';
}
// =======================privates===============================
/**
* The month in which daylight saving time starts. This value must be
* between Calendar.JANUARY and
* Calendar.DECEMBER inclusive. This value must not equal
* endMonth.
*
If useDaylight is false, this value is ignored.
* @serial
*/
private int startMonth;
/**
* This field has two possible interpretations:
*
startMode == DOW_IN_MONTHstartDay indicates the day of the month of
* startMonth on which daylight
* saving time starts, from 1 to 28, 30, or 31, depending on the
* startMonth.
* startMode != DOW_IN_MONTHstartDay indicates which startDayOfWeek in the
* month startMonth daylight
* saving time starts on. For example, a value of +1 and a
* startDayOfWeek of Calendar.SUNDAY indicates the
* first Sunday of startMonth. Likewise, +2 would indicate the
* second Sunday, and -1 the last Sunday. A value of 0 is illegal.
* If useDaylight is false, this value is ignored.
* @serial
*/
private int startDay;
/**
* The day of the week on which daylight saving time starts. This value
* must be between Calendar.SUNDAY and
* Calendar.SATURDAY inclusive.
*
If useDaylight is false or
* startMode == DAY_OF_MONTH, this value is ignored.
* @serial
*/
private int startDayOfWeek;
/**
* The time in milliseconds after midnight at which daylight saving
* time starts. This value is expressed as wall time, standard time,
* or UTC time, depending on the setting of startTimeMode.
*
If useDaylight is false, this value is ignored.
* @serial
*/
private int startTime;
/**
* The format of startTime, either WALL_TIME, STANDARD_TIME, or UTC_TIME.
* @serial
* @since 1.3
*/
private int startTimeMode;
/**
* The month in which daylight saving time ends. This value must be
* between Calendar.JANUARY and
* Calendar.UNDECIMBER. This value must not equal
* startMonth.
*
If useDaylight is false, this value is ignored.
* @serial
*/
private int endMonth;
/**
* This field has two possible interpretations:
*
endMode == DOW_IN_MONTHendDay indicates the day of the month of
* endMonth on which daylight
* saving time ends, from 1 to 28, 30, or 31, depending on the
* endMonth.
* endMode != DOW_IN_MONTHendDay indicates which endDayOfWeek in th
* month endMonth daylight
* saving time ends on. For example, a value of +1 and a
* endDayOfWeek of Calendar.SUNDAY indicates the
* first Sunday of endMonth. Likewise, +2 would indicate the
* second Sunday, and -1 the last Sunday. A value of 0 is illegal.
* If useDaylight is false, this value is ignored.
* @serial
*/
private int endDay;
/**
* The day of the week on which daylight saving time ends. This value
* must be between Calendar.SUNDAY and
* Calendar.SATURDAY inclusive.
*
If useDaylight is false or
* endMode == DAY_OF_MONTH, this value is ignored.
* @serial
*/
private int endDayOfWeek;
/**
* The time in milliseconds after midnight at which daylight saving
* time ends. This value is expressed as wall time, standard time,
* or UTC time, depending on the setting of endTimeMode.
*
If useDaylight is false, this value is ignored.
* @serial
*/
private int endTime;
/**
* The format of endTime, either WALL_TIME,
* STANDARD_TIME, or UTC_TIME.
* @serial
* @since 1.3
*/
private int endTimeMode;
/**
* The year in which daylight saving time is first observed. This is an {@link GregorianCalendar#AD AD}
* value. If this value is less than 1 then daylight saving time is observed
* for all AD years.
*
If useDaylight is false, this value is ignored.
* @serial
*/
private int startYear;
/**
* The offset in milliseconds between this zone and GMT. Negative offsets
* are to the west of Greenwich. To obtain local standard time,
* add the offset to GMT time. To obtain local wall time it may also be
* necessary to add dstSavings.
* @serial
*/
private int rawOffset;
/**
* A boolean value which is true if and only if this zone uses daylight
* saving time. If this value is false, several other fields are ignored.
* @serial
*/
private boolean useDaylight=false; // indicate if this time zone uses DST
private static final int millisPerHour = 60*60*1000;
private static final int millisPerDay = 24*millisPerHour;
/**
* This field was serialized in JDK 1.1, so we have to keep it that way
* to maintain serialization compatibility. However, there's no need to
* recreate the array each time we create a new time zone.
* @serial An array of bytes containing the values {31, 28, 31, 30, 31, 30,
* 31, 31, 30, 31, 30, 31}. This is ignored as of the Java 2 platform v1.2, however, it must
* be streamed out for compatibility with JDK 1.1.
*/
private final byte monthLength[] = staticMonthLength;
private final static byte staticMonthLength[] = {31,28,31,30,31,30,31,31,30,31,30,31};
private final static byte staticLeapMonthLength[] = {31,29,31,30,31,30,31,31,30,31,30,31};
/**
* Variables specifying the mode of the start rule. Takes the following
* values:
*
DOM_MODEDOW_IN_MONTH_MODEDOW_GE_DOM_MODEDOW_LE_DOM_MODEstartDay field.
* If useDaylight is false, this value is ignored.
* @serial
* @since 1.1.4
*/
private int startMode;
/**
* Variables specifying the mode of the end rule. Takes the following
* values:
*
DOM_MODEDOW_IN_MONTH_MODEDOW_GE_DOM_MODEDOW_LE_DOM_MODEendDay field.
* If useDaylight is false, this value is ignored.
* @serial
* @since 1.1.4
*/
private int endMode;
/**
* A positive value indicating the amount of time saved during DST in
* milliseconds.
* Typically one hour (3600000); sometimes 30 minutes (1800000).
*
If useDaylight is false, this value is ignored.
* @serial
* @since 1.1.4
*/
private int dstSavings;
private static final Gregorian gcal = CalendarSystem.getGregorianCalendar();
/**
* Cache values representing a single period of daylight saving
* time. When the cache values are valid, cacheStart is the start
* time (inclusive) of daylight saving time and cacheEnd is the
* end time (exclusive).
*
* cacheYear has a year value if both cacheStart and cacheEnd are
* in the same year. cacheYear is set to startYear - 1 if
* cacheStart and cacheEnd are in different years. cacheStart is 0
* if the cache values are void. cacheYear is a long to support
* Integer.MIN_VALUE - 1 (JCK requirement).
*/
private transient long cacheYear;
private transient long cacheStart;
private transient long cacheEnd;
/**
* Constants specifying values of startMode and endMode.
*/
private static final int DOM_MODE = 1; // Exact day of month, "Mar 1"
private static final int DOW_IN_MONTH_MODE = 2; // Day of week in month, "lastSun"
private static final int DOW_GE_DOM_MODE = 3; // Day of week after day of month, "Sun>=15"
private static final int DOW_LE_DOM_MODE = 4; // Day of week before day of month, "Sun<=21"
/**
* 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.
* @since 1.4
*/
public static final int WALL_TIME = 0; // Zero for backward compatibility
/**
* Constant for a mode of start or end time specified as standard time.
* @since 1.4
*/
public static final int STANDARD_TIME = 1;
/**
* Constant for a mode of start or end time specified as UTC. European
* Union rules are specified as UTC time, for example.
* @since 1.4
*/
public static final int UTC_TIME = 2;
// Proclaim compatibility with 1.1
static final long serialVersionUID = -403250971215465050L;
// the internal serial version which says which version was written
// - 0 (default) for version up to JDK 1.1.3
// - 1 for version from JDK 1.1.4, which includes 3 new fields
// - 2 for JDK 1.3, which includes 2 new fields
static final int currentSerialVersion = 2;
/**
* The version of the serialized data on the stream. Possible values:
*
startMode,
* endMode, and dstSavings.
* startTimeMode
* and endTimeMode.
* serialVersionOnStream
* is written.
* @serial
* @since 1.1.4
*/
private int serialVersionOnStream = currentSerialVersion;
synchronized private void invalidateCache() {
cacheYear = startYear - 1;
cacheStart = cacheEnd = 0;
}
//----------------------------------------------------------------------
// Rule representation
//
// We represent the following flavors of rules:
// 5 the fifth of the month
// lastSun the last Sunday in the month
// lastMon the last Monday in the month
// Sun>=8 first Sunday on or after the eighth
// Sun<=25 last Sunday on or before the 25th
// This is further complicated by the fact that we need to remain
// backward compatible with the 1.1 FCS. Finally, we need to minimize
// API changes. In order to satisfy these requirements, we support
// three representation systems, and we translate between them.
//
// INTERNAL REPRESENTATION
// This is the format SimpleTimeZone objects take after construction or
// streaming in is complete. Rules are represented directly, using an
// unencoded format. We will discuss the start rule only below; the end
// rule is analogous.
// startMode Takes on enumerated values DAY_OF_MONTH,
// DOW_IN_MONTH, DOW_AFTER_DOM, or DOW_BEFORE_DOM.
// startDay The day of the month, or for DOW_IN_MONTH mode, a
// value indicating which DOW, such as +1 for first,
// +2 for second, -1 for last, etc.
// startDayOfWeek The day of the week. Ignored for DAY_OF_MONTH.
//
// ENCODED REPRESENTATION
// This is the format accepted by the constructor and by setStartRule()
// and setEndRule(). It uses various combinations of positive, negative,
// and zero values to encode the different rules. This representation
// allows us to specify all the different rule flavors without altering
// the API.
// MODE startMonth startDay startDayOfWeek
// DOW_IN_MONTH_MODE >=0 !=0 >0
// DOM_MODE >=0 >0 ==0
// DOW_GE_DOM_MODE >=0 >0 <0
// DOW_LE_DOM_MODE >=0 <0 <0
// (no DST) don't care ==0 don't care
//
// STREAMED REPRESENTATION
// We must retain binary compatibility with the 1.1 FCS. The 1.1 code only
// handles DOW_IN_MONTH_MODE and non-DST mode, the latter indicated by the
// flag useDaylight. When we stream an object out, we translate into an
// approximate DOW_IN_MONTH_MODE representation so the object can be parsed
// and used by 1.1 code. Following that, we write out the full
// representation separately so that contemporary code can recognize and
// parse it. The full representation is written in a "packed" format,
// consisting of a version number, a length, and an array of bytes. Future
// versions of this class may specify different versions. If they wish to
// include additional data, they should do so by storing them after the
// packed representation below.
//----------------------------------------------------------------------
/**
* Given a set of encoded rules in startDay and startDayOfMonth, decode
* them and set the startMode appropriately. Do the same for endDay and
* endDayOfMonth. Upon entry, the day of week variables may be zero or
* negative, in order to indicate special modes. The day of month
* variables may also be negative. Upon exit, the mode variables will be
* set, and the day of week and day of month variables will be positive.
* This method also recognizes a startDay or endDay of zero as indicating
* no DST.
*/
private void decodeRules()
{
decodeStartRule();
decodeEndRule();
}
/**
* Decode the start rule and validate the parameters. The parameters are
* expected to be in encoded form, which represents the various rule modes
* by negating or zeroing certain values. Representation formats are:
* *
* DOW_IN_MONTH DOM DOW>=DOM DOW<=DOM no DST
* ------------ ----- -------- -------- ----------
* month 0..11 same same same don't care
* day -5..5 1..31 1..31 -1..-31 0
* dayOfWeek 1..7 0 -1..-7 -1..-7 don't care
* time 0..ONEDAY same same same don't care
*
* The range for month does not include UNDECIMBER since this class is
* really specific to GregorianCalendar, which does not use that month.
* The range for time includes ONEDAY (vs. ending at ONEDAY-1) because the
* end rule is an exclusive limit point. That is, the range of times that
* are in DST include those >= the start and < the end. For this reason,
* it should be possible to specify an end of ONEDAY in order to include the
* entire day. Although this is equivalent to time 0 of the following day,
* it's not always possible to specify that, for example, on December 31.
* While arguably the start range should still be 0..ONEDAY-1, we keep
* the start and end ranges the same for consistency.
*/
private void decodeStartRule() {
useDaylight = (startDay != 0) && (endDay != 0);
if (startDay != 0) {
if (startMonth < Calendar.JANUARY || startMonth > Calendar.DECEMBER) {
throw new IllegalArgumentException(
"Illegal start month " + startMonth);
}
if (startTime < 0 || startTime > millisPerDay) {
throw new IllegalArgumentException(
"Illegal start time " + startTime);
}
if (startDayOfWeek == 0) {
startMode = DOM_MODE;
} else {
if (startDayOfWeek > 0) {
startMode = DOW_IN_MONTH_MODE;
} else {
startDayOfWeek = -startDayOfWeek;
if (startDay > 0) {
startMode = DOW_GE_DOM_MODE;
} else {
startDay = -startDay;
startMode = DOW_LE_DOM_MODE;
}
}
if (startDayOfWeek > Calendar.SATURDAY) {
throw new IllegalArgumentException(
"Illegal start day of week " + startDayOfWeek);
}
}
if (startMode == DOW_IN_MONTH_MODE) {
if (startDay < -5 || startDay > 5) {
throw new IllegalArgumentException(
"Illegal start day of week in month " + startDay);
}
} else if (startDay < 1 || startDay > staticMonthLength[startMonth]) {
throw new IllegalArgumentException(
"Illegal start day " + startDay);
}
}
}
/**
* Decode the end rule and validate the parameters. This method is exactly
* analogous to decodeStartRule().
* @see decodeStartRule
*/
private void decodeEndRule() {
useDaylight = (startDay != 0) && (endDay != 0);
if (endDay != 0) {
if (endMonth < Calendar.JANUARY || endMonth > Calendar.DECEMBER) {
throw new IllegalArgumentException(
"Illegal end month " + endMonth);
}
if (endTime < 0 || endTime > millisPerDay) {
throw new IllegalArgumentException(
"Illegal end time " + endTime);
}
if (endDayOfWeek == 0) {
endMode = DOM_MODE;
} else {
if (endDayOfWeek > 0) {
endMode = DOW_IN_MONTH_MODE;
} else {
endDayOfWeek = -endDayOfWeek;
if (endDay > 0) {
endMode = DOW_GE_DOM_MODE;
} else {
endDay = -endDay;
endMode = DOW_LE_DOM_MODE;
}
}
if (endDayOfWeek > Calendar.SATURDAY) {
throw new IllegalArgumentException(
"Illegal end day of week " + endDayOfWeek);
}
}
if (endMode == DOW_IN_MONTH_MODE) {
if (endDay < -5 || endDay > 5) {
throw new IllegalArgumentException(
"Illegal end day of week in month " + endDay);
}
} else if (endDay < 1 || endDay > staticMonthLength[endMonth]) {
throw new IllegalArgumentException(
"Illegal end day " + endDay);
}
}
}
/**
* Make rules compatible to 1.1 FCS code. Since 1.1 FCS code only understands
* day-of-week-in-month rules, we must modify other modes of rules to their
* approximate equivalent in 1.1 FCS terms. This method is used when streaming
* out objects of this class. After it is called, the rules will be modified,
* with a possible loss of information. startMode and endMode will NOT be
* altered, even though semantically they should be set to DOW_IN_MONTH_MODE,
* since the rule modification is only intended to be temporary.
*/
private void makeRulesCompatible()
{
switch (startMode) {
case DOM_MODE:
startDay = 1 + (startDay / 7);
startDayOfWeek = Calendar.SUNDAY;
break;
case DOW_GE_DOM_MODE:
// A day-of-month of 1 is equivalent to DOW_IN_MONTH_MODE
// that is, Sun>=1 == firstSun.
if (startDay != 1) {
startDay = 1 + (startDay / 7);
}
break;
case DOW_LE_DOM_MODE:
if (startDay >= 30) {
startDay = -1;
} else {
startDay = 1 + (startDay / 7);
}
break;
}
switch (endMode) {
case DOM_MODE:
endDay = 1 + (endDay / 7);
endDayOfWeek = Calendar.SUNDAY;
break;
case DOW_GE_DOM_MODE:
// A day-of-month of 1 is equivalent to DOW_IN_MONTH_MODE
// that is, Sun>=1 == firstSun.
if (endDay != 1) {
endDay = 1 + (endDay / 7);
}
break;
case DOW_LE_DOM_MODE:
if (endDay >= 30) {
endDay = -1;
} else {
endDay = 1 + (endDay / 7);
}
break;
}
/*
* Adjust the start and end times to wall time. This works perfectly
* well unless it pushes into the next or previous day. If that
* happens, we attempt to adjust the day rule somewhat crudely. The day
* rules have been forced into DOW_IN_MONTH mode already, so we change
* the day of week to move forward or back by a day. It's possible to
* make a more refined adjustment of the original rules first, but in
* most cases this extra effort will go to waste once we adjust the day
* rules anyway.
*/
switch (startTimeMode) {
case UTC_TIME:
startTime += rawOffset;
break;
}
while (startTime < 0) {
startTime += millisPerDay;
startDayOfWeek = 1 + ((startDayOfWeek+5) % 7); // Back 1 day
}
while (startTime >= millisPerDay) {
startTime -= millisPerDay;
startDayOfWeek = 1 + (startDayOfWeek % 7); // Forward 1 day
}
switch (endTimeMode) {
case UTC_TIME:
endTime += rawOffset + dstSavings;
break;
case STANDARD_TIME:
endTime += dstSavings;
}
while (endTime < 0) {
endTime += millisPerDay;
endDayOfWeek = 1 + ((endDayOfWeek+5) % 7); // Back 1 day
}
while (endTime >= millisPerDay) {
endTime -= millisPerDay;
endDayOfWeek = 1 + (endDayOfWeek % 7); // Forward 1 day
}
}
/**
* Pack the start and end rules into an array of bytes. Only pack
* data which is not preserved by makeRulesCompatible.
*/
private byte[] packRules()
{
byte[] rules = new byte[6];
rules[0] = (byte)startDay;
rules[1] = (byte)startDayOfWeek;
rules[2] = (byte)endDay;
rules[3] = (byte)endDayOfWeek;
// As of serial version 2, include time modes
rules[4] = (byte)startTimeMode;
rules[5] = (byte)endTimeMode;
return rules;
}
/**
* Given an array of bytes produced by packRules, interpret them
* as the start and end rules.
*/
private void unpackRules(byte[] rules)
{
startDay = rules[0];
startDayOfWeek = rules[1];
endDay = rules[2];
endDayOfWeek = rules[3];
// As of serial version 2, include time modes
if (rules.length >= 6) {
startTimeMode = rules[4];
endTimeMode = rules[5];
}
}
/**
* Pack the start and end times into an array of bytes. This is required
* as of serial version 2.
*/
private int[] packTimes() {
int[] times = new int[2];
times[0] = startTime;
times[1] = endTime;
return times;
}
/**
* Unpack the start and end times from an array of bytes. This is required
* as of serial version 2.
*/
private void unpackTimes(int[] times) {
startTime = times[0];
endTime = times[1];
}
/**
* Save the state of this object to a stream (i.e., serialize it).
*
* @serialData We write out two formats, a JDK 1.1 compatible format, using
* DOW_IN_MONTH_MODE rules, in the required section, followed
* by the full rules, in packed format, in the optional section. The
* optional section will be ignored by JDK 1.1 code upon stream in.
* Contents of the optional section: The length of a byte array is
* emitted (int); this is 4 as of this release. The byte array of the given
* length is emitted. The contents of the byte array are the true values of
* the fields startDay, startDayOfWeek,
* endDay, and endDayOfWeek. The values of these
* fields in the required section are approximate values suited to the rule
* mode DOW_IN_MONTH_MODE, which is the only mode recognized by
* JDK 1.1.
*/
private void writeObject(ObjectOutputStream stream)
throws IOException
{
// Construct a binary rule
byte[] rules = packRules();
int[] times = packTimes();
// Convert to 1.1 FCS rules. This step may cause us to lose information.
makeRulesCompatible();
// Write out the 1.1 FCS rules
stream.defaultWriteObject();
// Write out the binary rules in the optional data area of the stream.
stream.writeInt(rules.length);
stream.write(rules);
stream.writeObject(times);
// Recover the original rules. This recovers the information lost
// by makeRulesCompatible.
unpackRules(rules);
unpackTimes(times);
}
/**
* Reconstitute this object from a stream (i.e., deserialize it).
*
* We handle both JDK 1.1
* binary formats and full formats with a packed byte array.
*/
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException
{
stream.defaultReadObject();
if (serialVersionOnStream < 1) {
// Fix a bug in the 1.1 SimpleTimeZone code -- namely,
// startDayOfWeek and endDayOfWeek were usually uninitialized. We can't do
// too much, so we assume SUNDAY, which actually works most of the time.
if (startDayOfWeek == 0) {
startDayOfWeek = Calendar.SUNDAY;
}
if (endDayOfWeek == 0) {
endDayOfWeek = Calendar.SUNDAY;
}
// The variables dstSavings, startMode, and endMode are post-1.1, so they
// won't be present if we're reading from a 1.1 stream. Fix them up.
startMode = endMode = DOW_IN_MONTH_MODE;
dstSavings = millisPerHour;
} else {
// For 1.1.4, in addition to the 3 new instance variables, we also
// store the actual rules (which have not be made compatible with 1.1)
// in the optional area. Read them in here and parse them.
int length = stream.readInt();
byte[] rules = new byte[length];
stream.readFully(rules);
unpackRules(rules);
}
if (serialVersionOnStream >= 2) {
int[] times = (int[]) stream.readObject();
unpackTimes(times);
}
serialVersionOnStream = currentSerialVersion;
}
}