sun.util.calendar

Class ZoneInfo

java.lang.Object

java.util.TimeZone

sun.util.calendar.ZoneInfo

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class ZoneInfo
extends java.util.TimeZone

ZoneInfo is an implementation subclass of TimeZone that represents GMT offsets and daylight saving time transitions of a time zone.

The daylight saving time transitions are described in the transitions table consisting of a chronological sequence of transitions of GMT offset and/or daylight saving time changes. Since all transitions are represented in UTC, in theory, ZoneInfo can be used with any calendar systems except for the getOffset method that takes Gregorian calendar date fields.

This table covers transitions from 1900 until 2037 (as of version 1.4), Before 1900, it assumes that there was no daylight saving time and the getOffset methods always return the getRawOffset() value. No Local Mean Time is supported. If a specified date is beyond the transition table and this time zone is supposed to observe daylight saving time in 2037, it delegates operations to a SimpleTimeZone object created using the daylight saving time schedule as of 2037.

The date items, transitions, GMT offset(s), etc. are read from a database file. See ZoneInfoFile for details.

Since:

1.4

See Also:

SimpleTimeZone, Serialized Form

Field Summary

Fields inherited from class java.util.TimeZone

LONG, SHORT

Constructor Summary

Constructors

Constructor and Description
ZoneInfo() A constructor.
ZoneInfo(java.lang.String ID, int rawOffset) A Constructor for CustomID.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	clone() Returns a copy of this ZoneInfo.
boolean	equals(java.lang.Object obj) Compares the equity of two ZoneInfo objects.
static java.util.Map<java.lang.String,java.lang.String>	getAliasTable() Returns a Map from alias time zone IDs to their standard time zone IDs.
static java.lang.String[]	getAvailableIDs() Gets all available IDs supported in the Java run-time.
static java.lang.String[]	getAvailableIDs(int rawOffset) Gets all available IDs that have the same value as the specified raw GMT offset.
int	getDSTSavings() Returns the amount of time in milliseconds that the clock is advanced during daylight saving time is in effect in its last daylight saving time rule.
java.util.SimpleTimeZone	getLastRuleInstance() Returns a SimpleTimeZone object that represents the last known daylight saving time rules.
int	getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds) Returns the difference in milliseconds between local time and UTC, taking into account both the raw offset and the effect of daylight savings, for the specified date and time.
int	getOffset(long date) Returns the difference in milliseconds between local time and UTC of given time, taking into account both the raw offset and the effect of daylight savings.
int	getOffsets(long utc, int[] offsets)
int	getOffsetsByStandard(long standard, int[] offsets)
int	getOffsetsByWall(long wall, int[] offsets)
int	getRawOffset() Returns the GMT offset of the current date.
static java.util.TimeZone	getTimeZone(java.lang.String ID) Gets the ZoneInfo for the given ID.
int	hashCode() Returns a hash code value calculated from the GMT offset and transitions.
boolean	hasSameRules(java.util.TimeZone other) Returns true if this zone has the same raw GMT offset value and transition table as another zone info.
boolean	inDaylightTime(java.util.Date date) Queries if the specified date is in Daylight Saving Time.
boolean	isDirty()
void	setRawOffset(int offsetMillis) Sets the base time zone offset from GMT.
java.lang.String	toString() Returns a string representation of this time zone.
boolean	useDaylightTime() Queries if this time zone uses Daylight Saving Time in the last known rule.

Methods inherited from class java.util.TimeZone

getDefault, getDisplayName, getDisplayName, getDisplayName, getDisplayName, getID, observesDaylightTime, setDefault, setID

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ZoneInfo

public ZoneInfo()

A constructor.

ZoneInfo

public ZoneInfo(java.lang.String ID,
        int rawOffset)

A Constructor for CustomID.

Method Detail

getOffset

public int getOffset(long date)

Returns the difference in milliseconds between local time and UTC of given time, taking into account both the raw offset and the effect of daylight savings.

Overrides:

getOffset in class java.util.TimeZone

Parameters:

date - the milliseconds in UTC

Returns:

the milliseconds to add to UTC to get local wall time

getOffsets

public int getOffsets(long utc,
             int[] offsets)

getOffsetsByStandard

public int getOffsetsByStandard(long standard,
                       int[] offsets)

getOffsetsByWall

public int getOffsetsByWall(long wall,
                   int[] offsets)

getOffset

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

Returns the difference in milliseconds between local time and UTC, taking into account both the raw offset and the effect of daylight savings, for the specified date and time. This method assumes that the start and end month are distinct. This method assumes a Gregorian calendar for calculations.

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

Specified by:

getOffset in class java.util.TimeZone

Parameters:

era - The era of the given date. The value must be either GregorianCalendar.AD or GregorianCalendar.BC.

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.

setRawOffset

public void setRawOffset(int offsetMillis)

Sets the base time zone offset from GMT. This operation modifies all the transitions of this ZoneInfo object, including historical ones, if applicable.

Specified by:

setRawOffset in class java.util.TimeZone

Parameters:

offsetMillis - the base time zone offset to GMT.

See Also:

getRawOffset

getRawOffset

public int getRawOffset()

Returns the GMT offset of the current date. This GMT offset value is not modified during Daylight Saving Time.

Specified by:

getRawOffset in class java.util.TimeZone

Returns:

the GMT offset value in milliseconds to add to UTC time to get local standard time

isDirty

public boolean isDirty()

useDaylightTime

public boolean useDaylightTime()

Queries if this time zone uses Daylight Saving Time in the last known rule.

Specified by:

useDaylightTime in class java.util.TimeZone

inDaylightTime

public boolean inDaylightTime(java.util.Date date)

Queries if the specified date is in Daylight Saving Time.

Specified by:

inDaylightTime in class java.util.TimeZone

getDSTSavings

public int getDSTSavings()

Returns the amount of time in milliseconds that the clock is advanced during daylight saving time is in effect in its last daylight saving time rule.

Overrides:

getDSTSavings in class java.util.TimeZone

Returns:

the number of milliseconds the time is advanced with respect to standard time when daylight saving time is in effect.

toString

public java.lang.String toString()

Returns a string representation of this time zone.

Overrides:

toString in class java.lang.Object

Returns:

the string

getAvailableIDs

public static java.lang.String[] getAvailableIDs()

Gets all available IDs supported in the Java run-time.

Returns:

an array of time zone IDs.

getAvailableIDs

public static java.lang.String[] getAvailableIDs(int rawOffset)

Gets all available IDs that have the same value as the specified raw GMT offset.

Parameters:

rawOffset - the GMT offset in milliseconds. This value should not include any daylight saving time.

Returns:

an array of time zone IDs.

getTimeZone

public static java.util.TimeZone getTimeZone(java.lang.String ID)

Gets the ZoneInfo for the given ID.

Parameters:

ID - the ID for a ZoneInfo. See TimeZone for detail.

Returns:

the specified ZoneInfo object, or null if there is no time zone of the ID.

getLastRuleInstance

public java.util.SimpleTimeZone getLastRuleInstance()

Returns a SimpleTimeZone object that represents the last known daylight saving time rules.

Returns:

a SimpleTimeZone object or null if this time zone doesn't observe DST.

clone

public java.lang.Object clone()

Returns a copy of this ZoneInfo.

Overrides:

clone in class java.util.TimeZone

hashCode

public int hashCode()

Returns a hash code value calculated from the GMT offset and transitions.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code of this time zone

equals

public boolean equals(java.lang.Object obj)

Compares the equity of two ZoneInfo objects.

Overrides:

equals in class java.lang.Object

Parameters:

obj - the object to be compared with

Returns:

true if given object is same as this ZoneInfo object, false otherwise.

hasSameRules

public boolean hasSameRules(java.util.TimeZone other)

Returns true if this zone has the same raw GMT offset value and transition table as another zone info. If the specified TimeZone object is not a ZoneInfo instance, this method returns true if the specified TimeZone object has the same raw GMT offset value with no daylight saving time.

Overrides:

hasSameRules in class java.util.TimeZone

Parameters:

other - the ZoneInfo object to be compared with

Returns:

true if the given TimeZone has the same GMT offset and transition information; false, otherwise.

getAliasTable

public static java.util.Map<java.lang.String,java.lang.String> getAliasTable()

Returns a Map from alias time zone IDs to their standard time zone IDs.

Returns:

the Map that holds the mappings from alias time zone IDs to their standard time zone IDs, or null if ZoneInfoMappings file is not available.