java.time.zone

Class TzdbZoneRulesProvider

java.lang.Object

java.time.zone.ZoneRulesProvider

java.time.zone.TzdbZoneRulesProvider

public class TzdbZoneRulesProvider
extends ZoneRulesProvider

Provides zone rules for the time-zones defined by IANA Time Zone Database (TZDB).

Constructor Summary

Constructors

Constructor and Description
TzdbZoneRulesProvider() Creates a provider and initializes it.

Method Summary

Modifier and Type	Method and Description
protected ZoneRules	provideRules(String zoneId, boolean forCaching) SPI method to get the rules for the zone ID.
protected NavigableMap<String,ZoneRules>	provideVersions(String zoneId) SPI method to get the history of rules for the zone ID.
protected Set<String>	provideZoneIds() SPI method to get the available zone IDs.

Methods inherited from class java.time.zone.ZoneRulesProvider

getAvailableZoneIds, getRules, getVersions, provideRefresh, refresh

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TzdbZoneRulesProvider

public TzdbZoneRulesProvider()
                      throws IOException

Creates a provider and initializes it.

The initialization phase attempts to read from the tzdb binary resource that contains the zone rules. If it fails to open or read the resource, it will throw an exception.

Throws:

IOException - if the tzdb binary resource could not be open/read, or the tzdb data is not valid

Method Detail

provideRules

@Nullable
protected ZoneRules provideRules(String zoneId,
                                           boolean forCaching)

Description copied from class: ZoneRulesProvider

SPI method to get the rules for the zone ID.

This loads the rules for the specified zone ID. The provider implementation must validate that the zone ID is valid and available, throwing a ZoneRulesException if it is not. The result of the method in the valid case depends on the caching flag.

If the provider implementation is not dynamic, then the result of the method must be the non-null set of rules selected by the ID.

If the provider implementation is dynamic, then the flag gives the option of preventing the returned rules from being cached in ZoneId. When the flag is true, the provider is permitted to return null, where null will prevent the rules from being cached in ZoneId. When the flag is false, the provider must return non-null rules.

Specified by:

provideRules in class ZoneRulesProvider

Parameters:

zoneId - the zone ID as defined by ZoneId, not null

forCaching - whether the rules are being queried for caching, true if the returned rules will be cached by ZoneId, false if they will be returned to the user without being cached in ZoneId

Returns:

the rules, null if forCaching is true and this is a dynamic provider that wants to prevent caching in ZoneId, otherwise not null

provideVersions

protected NavigableMap<String,ZoneRules> provideVersions(String zoneId)

Description copied from class: ZoneRulesProvider

SPI method to get the history of rules for the zone ID.

This returns a map of historical rules keyed by a version string. The exact meaning and format of the version is provider specific. The version must follow lexicographical order, thus the returned map will be ordered from the oldest known rules to the newest available rules.

Implementations must provide a result for each valid zone ID, however they do not have to provide a history of rules. Thus, the map will contain at least one element, and will only contain more than one element if historical rule information is available.

The returned versions remain available and valid for the lifetime of the application. A dynamic provider may increase the set of versions as more data becomes available.

Specified by:

provideVersions in class ZoneRulesProvider

Parameters:

zoneId - the zone ID as defined by ZoneId, not null

Returns:

a modifiable copy of the history of the rules for the ID, sorted from oldest to newest, not null

provideZoneIds

protected Set<String> provideZoneIds()

Description copied from class: ZoneRulesProvider

SPI method to get the available zone IDs.

This obtains the IDs that this ZoneRulesProvider provides. A provider should provide data for at least one zone ID.

The returned zone IDs remain available and valid for the lifetime of the application. A dynamic provider may increase the set of IDs as more data becomes available.

Specified by:

provideZoneIds in class ZoneRulesProvider

Returns:

the set of zone IDs being provided, not null