/** * Gets the history of rules for the zone ID. * <p> * Time-zones are defined by governments and change frequently. * This method allows applications to find the history of changes to the * rules for a single zone ID. The map is keyed by a string, which is the * version string associated with the rules. * <p> * 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'. * <p> * 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 always contain one element, and will only contain more * than one element if historical rule information is available. * * @param zoneId the zone region ID as used by {@code ZoneId}, not null * @return a modifiable copy of the history of the rules for the ID, sorted * from oldest to newest, not null * @throws ZoneRulesException if history cannot be obtained for the zone ID */ public static NavigableMap<String, ZoneRules> getVersions(String zoneId) { Jdk8Methods.requireNonNull(zoneId, "zoneId"); return getProvider(zoneId).provideVersions(zoneId); }
/** * Gets the history of rules for the zone ID. * <p> * Time-zones are defined by governments and change frequently. * This method allows applications to find the history of changes to the * rules for a single zone ID. The map is keyed by a string, which is the * version string associated with the rules. * <p> * 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'. * <p> * 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 always contain one element, and will only contain more * than one element if historical rule information is available. * * @param zoneId the zone region ID as used by {@code ZoneId}, not null * @return a modifiable copy of the history of the rules for the ID, sorted * from oldest to newest, not null * @throws ZoneRulesException if history cannot be obtained for the zone ID */ public static NavigableMap<String, ZoneRules> getVersions(String zoneId) { Jdk8Methods.requireNonNull(zoneId, "zoneId"); return getProvider(zoneId).provideVersions(zoneId); }