net.sf.saxon.expr.number
Class NamedTimeZone

java.lang.Object
  net.sf.saxon.expr.number.NamedTimeZone

public class NamedTimeZone
extends Object

This class attempts to identify a timezone name, given the date (including the time zone offset) and the country. The process is heuristic: sometimes there is more than one timezone that matches this information, sometimes there is none, but the class simply does its best. This is in support of the XSLT format-date() function.

Constructor Summary

NamedTimeZone()

Method Summary

static int	civilTimeOffset(DateTimeValue date, String olsenName) Get the civil time offset to be made to a given date/time in a given civil timezone.
static String	formatTimeZoneOffset(DateTimeValue timeValue) Format a timezone in numeric form for example +03:00 (or Z for +00:00)
static String	getOlsenTimeZoneName(DateTimeValue date, String country) Try to identify a timezone name corresponding to a given date (including time zone) and a given country.
static String	getTimeZoneNameForDate(DateTimeValue date, String country) Try to identify a timezone name corresponding to a given date (including time zone) and a given country.
static Boolean	inSummerTime(DateTimeValue date, String region) Determine whether a given date/time is in summer time (daylight savings time) in a given region.

Methods inherited from class java.lang.Object

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

Constructor Detail

NamedTimeZone

public NamedTimeZone()

Method Detail

getTimeZoneNameForDate

public static String getTimeZoneNameForDate(DateTimeValue date,
                                            String country)

Try to identify a timezone name corresponding to a given date (including time zone) and a given country. Note that this takes account of Java's calendar of daylight savings time changes in different countries. The returned value is the convenional short timezone name, for example PDT for Pacific Daylight Time

Parameters:

date - the dateTimeValue, including timezone

country - the two-letter ISO country code

Returns:

the short timezone name if a timezone with the given time displacement is in use in the country in question (on the appropriate date, if known). Otherwise, the formatted (numeric) timezone offset. If the dateTimeValue supplied has no timezone, return a zero-length string.

formatTimeZoneOffset

public static String formatTimeZoneOffset(DateTimeValue timeValue)

Format a timezone in numeric form for example +03:00 (or Z for +00:00)

Parameters:

timeValue - the value whose timezone is to be formatted

Returns:

the formatted timezone

getOlsenTimeZoneName

public static String getOlsenTimeZoneName(DateTimeValue date,
                                          String country)

Try to identify a timezone name corresponding to a given date (including time zone) and a given country. Note that this takes account of Java's calendar of daylight savings time changes in different countries. The returned value is the Olsen time zone name, for example "Pacific/Los_Angeles", followed by an asterisk (*) if the time is in daylight savings time in that timezone.

Parameters:

date - the dateTimeValue, including timezone

country - the country, as a two-letter code

Returns:

the Olsen timezone name if a timezone with the given time displacement is in use in the country in question (on the appropriate date, if known). In this case an asterisk is appended to the result if the date/time is in daylight savings time. Otherwise, the formatted (numeric) timezone offset. If the dateTimeValue supplied has no timezone, return a zero-length string.

inSummerTime

public static Boolean inSummerTime(DateTimeValue date,
                                   String region)

Determine whether a given date/time is in summer time (daylight savings time) in a given region. This relies on the Java database of changes to daylight savings time. Since summer time changes are set by civil authorities the information is not necessarily reliable when applied to dates in the future.

Parameters:

date - the date/time in question

region - either the two-letter ISO country code, or an Olsen timezone name such as "America/New_York" or "Europe/Lisbon". If the country code denotes a country spanning several timezones, such as the US, then one of them is chosen arbitrarily.

Returns:

true if the date/time is known to be in summer time in the relevant country; false if it is known not to be in summer time; null if there is no timezone or if no information is available for the specified region.

civilTimeOffset

public static int civilTimeOffset(DateTimeValue date,
                                  String olsenName)

Get the civil time offset to be made to a given date/time in a given civil timezone. For example, if the timezone is America/New_York, the civil time offset will be -5 hours (= 5 x 3600000 ms) during the winter and -4 hours (=4 x 3600000 ms) during the summer

Parameters:

date - the date/time in question. If this has no timezone, it is assumed to be in GMT.

olsenName - the Olsen name of the timezone, for example Europe/Lisbon

Returns:

the civil time offset, in milliseconds, to be applied to the given date/time