IcuZoneRulesProvider

public class IcuZoneRulesProvider extends ZoneRulesProvider

A ZoneRulesProvider that generates rules from ICU4J TimeZones. This provider ensures that classes in java.time use the same time zone information as ICU4J.

Public Constructor Summary

Protected Method Summary

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

Inherited Method Summary

Public Constructors

public IcuZoneRulesProvider ()

Protected Methods

protected ZoneRules provideRules (String zoneId, boolean forCaching)

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.

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

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

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 order from the oldest known rules to the newest available rules. The default 'TZDB' group uses version numbering consisting of the year followed by a letter, such as '2009e' or '2012f'.

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.

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

protected Set<String> provideZoneIds ()

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.

Returns
  • the set of zone IDs being provided, not null