net.time4j.tz

Interface ZoneProvider

public interface ZoneProvider

SPI interface which encapsulates the timezone repository and provides all necessary data for a given timezone id.

Implementations are usually stateless and should normally not try to manage a cache. Instead Time4J uses its own cache. The fact that this interface is used per java.util.ServiceLoader requires a concrete implementation to offer a public no-arg constructor.

Since:

2.0

Author:

Meno Hochschild

See Also:

ServiceLoader

Method Summary

Methods

Modifier and Type	Method and Description
Map<String,String>	getAliases() Gets an alias table whose keys represent alternative identifiers mapped to other aliases or finally canonical timezone IDs..
Set<String>	getAvailableIDs() Gets all available and supported timezone identifiers.
String	getLocation() Describes the location or source of the repository.
String	getName() Gets the name of the underlying repository.
String	getVersion() Queries the version of the underlying repository.
boolean	isFallbackEnabled() Determines if in case of a failed search another timezone should be permitted as alternative with possibly different rules.
TransitionHistory	load(String zoneID, boolean fallback) Loads an offset transition table for given timezone id.

Method Detail

getAvailableIDs

Set<String> getAvailableIDs()

Gets all available and supported timezone identifiers.

Returns:

unmodifiable set of timezone ids

See Also:

TimeZone.getAvailableIDs()

getAliases

Map<String,String> getAliases()

Gets an alias table whose keys represent alternative identifiers mapped to other aliases or finally canonical timezone IDs..

Example: "PST" => "America/Los_Angeles".

Returns:

map from all timezone aliases to canoncial ids

load

TransitionHistory load(String zoneID,
                     boolean fallback)

Loads an offset transition table for given timezone id.

This callback method has a second argument which indicates if Time4J wants this method to return exactly matching data (default) or permits the use of aliases (only possible if the method isFallbackEnabled() returns true).

Parameters:

zoneID - timezone id (i.e. "Europe/London")

fallback - fallback allowed if a timezone id cannot be found, not even by alias?

Returns:

timezone history or null if there are no data

Throws:

IllegalStateException - if timezone database is broken

See Also:

getAvailableIDs(), getAliases(), isFallbackEnabled(), TimeZone.getTimeZone(String)

isFallbackEnabled

boolean isFallbackEnabled()

Determines if in case of a failed search another timezone should be permitted as alternative with possibly different rules.

Returns:

boolean

See Also:

load(String, boolean)

getName

String getName()

Gets the name of the underlying repository.

The Olson/IANA-repository has the name "TZDB".

Returns:

String

getLocation

String getLocation()

Describes the location or source of the repository.

Returns:

String which refers to an URI or empty if unknown

getVersion

String getVersion()

Queries the version of the underlying repository.

In most cases the version has the Olson format starting with a four-digit year number followed by a small letter in range a-z.

Returns:

String (for example "2011n") or empty if unknown