Class TimeZoneNames
- All Implemented Interfaces:
Serializable
TimeZoneNames
is an abstract class representing the time zone display name data model defined
by UTS#35 Unicode Locale Data Markup Language (LDML).
The model defines meta zone, which is used for storing a set of display names. A meta zone can be shared
by multiple time zones. Also a time zone may have multiple meta zone historic mappings.
For example, people in the United States refer the zone used by the east part of North America as "Eastern Time". The tz database contains multiple time zones "America/New_York", "America/Detroit", "America/Montreal" and some others that belong to "Eastern Time". However, assigning different display names to these time zones does not make much sense for most of people.
In CLDR (which uses LDML for representing locale data), the display name "Eastern Time" is stored as long generic display name of a meta zone identified by the ID "America_Eastern". Then, there is another table maintaining the historic mapping to meta zones for each time zone. The time zones in the above example ("America/New_York", "America/Detroit"...) are mapped to the meta zone "America_Eastern".
Sometimes, a time zone is mapped to a different time zone in the past. For example, "America/Indiana/Knox" had been moving "Eastern Time" and "Central Time" back and forth. Therefore, it is necessary that time zone to meta zones mapping data are stored by date range.
Note:
TimeZoneFormat
assumes an instance of TimeZoneNames
is immutable. If you want to provide
your own TimeZoneNames
implementation and use it with TimeZoneFormat
, you must follow
the contract.
The methods in this class assume that time zone IDs are already canonicalized. For example, you may not get proper
result returned by a method with time zone ID "America/Indiana/Indianapolis", because it's not a canonical time zone
ID (the canonical time zone ID for the time zone is "America/Indianapolis". See
TimeZone.getCanonicalID(String)
about ICU canonical time zone IDs.
In CLDR, most of time zone display names except location names are provided through meta zones. But a time zone may have a specific name that is not shared with other time zones. For example, time zone "Europe/London" has English long name for standard time "Greenwich Mean Time", which is also shared with other time zones. However, the long name for daylight saving time is "British Summer Time", which is only used for "Europe/London".
getTimeZoneDisplayName(String, NameType)
is designed for accessing a name only used by a single time zone.
But is not necessarily mean that a subclass implementation use the same model with CLDR. A subclass implementation
may provide time zone names only through getTimeZoneDisplayName(String, NameType)
, or only through
getMetaZoneDisplayName(String, NameType)
, or both.
The default TimeZoneNames
implementation returned by getInstance(ULocale)
uses the locale data
imported from CLDR. In CLDR, set of meta zone IDs and mappings between zone IDs and meta zone IDs are shared by all
locales. Therefore, the behavior of getAvailableMetaZoneIDs()
, getAvailableMetaZoneIDs(String)
,
getMetaZoneID(String, long)
, and getReferenceZoneID(String, String)
won't be changed no matter
what locale is used for getting an instance of TimeZoneNames
.
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic class
Deprecated.This API is ICU internal only.static class
AMatchInfo
represents a time zone name match used byfind(CharSequence, int, EnumSet)
.static enum
Time zone display name types -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
Sole constructor for invocation by subclass constructors. -
Method Summary
Modifier and TypeMethodDescriptionfind
(CharSequence text, int start, EnumSet<TimeZoneNames.NameType> types) Finds time zone name prefix matches for the input text at the given offset and returns a collection of the matches.Returns an immutable set of all available meta zone IDs.Returns an immutable set of all available meta zone IDs used by the given time zone.final String
getDisplayName
(String tzID, TimeZoneNames.NameType type, long date) Returns the display name of the time zone at the given date.void
getDisplayNames
(String tzID, TimeZoneNames.NameType[] types, long date, String[] dest, int destOffset) Deprecated.This API is ICU internal only.Returns the exemplar location name for the given time zone.static TimeZoneNames
getInstance
(ULocale locale) Returns an instance ofTimeZoneNames
for the specified locale.static TimeZoneNames
getInstance
(Locale locale) Returns an instance ofTimeZoneNames
for the specifiedLocale
.abstract String
getMetaZoneDisplayName
(String mzID, TimeZoneNames.NameType type) Returns the display name of the meta zone.abstract String
getMetaZoneID
(String tzID, long date) Returns the meta zone ID for the given canonical time zone ID at the given date.abstract String
getReferenceZoneID
(String mzID, String region) Returns the reference zone ID for the given meta zone ID for the region.abstract String
getTimeZoneDisplayName
(String tzID, TimeZoneNames.NameType type) Returns the display name of the time zone.static TimeZoneNames
getTZDBInstance
(ULocale locale) Returns an instance ofTimeZoneNames
containing only short specific zone names (TimeZoneNames.NameType.SHORT_STANDARD
andTimeZoneNames.NameType.SHORT_DAYLIGHT
), compatible with the IANA tz database's zone abbreviations (not localized).void
Deprecated.This API is ICU internal only.
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Constructor Details
-
TimeZoneNames
protected TimeZoneNames()Sole constructor for invocation by subclass constructors.
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Method Details
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getInstance
Returns an instance ofTimeZoneNames
for the specified locale.- Parameters:
locale
- The locale.- Returns:
- An instance of
TimeZoneNames
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getInstance
Returns an instance ofTimeZoneNames
for the specifiedLocale
.- Parameters:
locale
- TheLocale
.- Returns:
- An instance of
TimeZoneDisplayNames
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getTZDBInstance
Returns an instance ofTimeZoneNames
containing only short specific zone names (TimeZoneNames.NameType.SHORT_STANDARD
andTimeZoneNames.NameType.SHORT_DAYLIGHT
), compatible with the IANA tz database's zone abbreviations (not localized).
Note: The input locale is used for resolving ambiguous names (e.g. "IST" is parsed as Israel Standard Time for Israel, while it is parsed as India Standard Time for all other regions). The zone names returned by this instance are not localized. -
getAvailableMetaZoneIDs
Returns an immutable set of all available meta zone IDs.- Returns:
- An immutable set of all available meta zone IDs.
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getAvailableMetaZoneIDs
Returns an immutable set of all available meta zone IDs used by the given time zone.- Parameters:
tzID
- The canonical time zone ID.- Returns:
- An immutable set of all available meta zone IDs used by the given time zone.
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getMetaZoneID
Returns the meta zone ID for the given canonical time zone ID at the given date.- Parameters:
tzID
- The canonical time zone ID.date
- The date.- Returns:
- The meta zone ID for the given time zone ID at the given date. If the time zone does not have a corresponding meta zone at the given date or the implementation does not support meta zones, null is returned.
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getReferenceZoneID
Returns the reference zone ID for the given meta zone ID for the region. Note: Each meta zone must have a reference zone associated with a special region "001" (world). Some meta zones may have region specific reference zone IDs other than the special region "001". When a meta zone does not have any region specific reference zone IDs, this method return the reference zone ID for the special region "001" (world).- Parameters:
mzID
- The meta zone ID.region
- The region.- Returns:
- The reference zone ID ("golden zone" in the LDML specification) for the given time zone ID for the region. If the meta zone is unknown or the implementation does not support meta zones, null is returned.
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getMetaZoneDisplayName
Returns the display name of the meta zone.- Parameters:
mzID
- The meta zone ID.type
- The display name type. SeeTimeZoneNames.NameType
.- Returns:
- The display name of the meta zone. When this object does not have a localized display name for the given meta zone with the specified type or the implementation does not provide any display names associated with meta zones, null is returned.
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getDisplayName
Returns the display name of the time zone at the given date.Note: This method calls the subclass's
getTimeZoneDisplayName(String, NameType)
first. When the result is null, this method callsgetMetaZoneID(String, long)
to get the meta zone ID mapped from the time zone, then callsgetMetaZoneDisplayName(String, NameType)
.- Parameters:
tzID
- The canonical time zone ID.type
- The display name type. SeeTimeZoneNames.NameType
.date
- The date- Returns:
- The display name for the time zone at the given date. When this object does not have a localized display name for the time zone with the specified type and date, null is returned.
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getTimeZoneDisplayName
Returns the display name of the time zone. UnlikegetDisplayName(String, NameType, long)
, this method does not get a name from a meta zone used by the time zone.- Parameters:
tzID
- The canonical time zone ID.type
- The display name type. SeeTimeZoneNames.NameType
.- Returns:
- The display name for the time zone. When this object does not have a localized display name for the given time zone with the specified type, null is returned.
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getExemplarLocationName
Returns the exemplar location name for the given time zone. When this object does not have a localized location name, the default implementation may still returns a programmatically generated name with the logic described below.- Check if the ID contains "/". If not, return null.
- Check if the ID does not start with "Etc/" or "SystemV/". If it does, return null.
- Extract a substring after the last occurrence of "/".
- Replace "_" with " ".
- Parameters:
tzID
- The canonical time zone ID- Returns:
- The exemplar location name for the given time zone, or null when a localized location name is not available and the fallback logic described above cannot extract location from the ID.
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find
public Collection<TimeZoneNames.MatchInfo> find(CharSequence text, int start, EnumSet<TimeZoneNames.NameType> types) Finds time zone name prefix matches for the input text at the given offset and returns a collection of the matches.- Parameters:
text
- the text.start
- the starting offset within the text.types
- the set of name types, ornull
for all name types.- Returns:
- A collection of matches.
- See Also:
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loadAllDisplayNames
Deprecated.This API is ICU internal only. -
getDisplayNames
@Deprecated public void getDisplayNames(String tzID, TimeZoneNames.NameType[] types, long date, String[] dest, int destOffset) Deprecated.This API is ICU internal only.
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