Appendix C       Time Zones


This appendix describes how iPlanet Calendar Server processes time zones. It also describes how an administrator can add a new time zone table or modify the time zone tables supplied with iPlanet Calendar Server.

The file timezones.ics shown on page 166 contains the representation of the time zones supported by iPlanet Calendar Server. This file is located in the server-root/cal/bin/data directory (for example, opt/SUNWics5/cal/bin/data). This file contains 91 time zones.

At startup, the iPlanet Calendar Server reads the file timezones.ics, then generates 91 in-memory time zones and stores them in an array (cal_array). Therefore, all the time zones are kept in memory while the server is running.

If a WCAP command includes a time zone ID (tzid), it should reference a time zone in the cal_array. For more information on WCAP, refer to the iPlanet Calendar Server Programmer's Reference.

For example, if a command such as storeevents or fetchcomponents_by_range specifies a tzid parameter, the parameter value must be a tzid that is defined in the list of 91 time zones. The server will return data in that time zone and all data will have dates applied to that time zone.

If the command specifies an unrecognized tzid, the server will return a GMT time zone by default. All data returned on that command will have its dates applied in GMT.

Time Zone Administration

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This section describes how to:

• modify the iPlanet Calendar Server time zone list

• add a new time zone to iPlanet Calendar Server

To modify the iPlanet Calendar Server time zone list, an administrator must edit the file timezones.ics located in the server-root/cal/bin/data directory (for example, opt/SUNWics5/cal/bin/data). This file contains the iPlanet Calendar Server format of 91 time zones. (See iCalendar Specification for more details about the VTIMEZONE format).

Time zones are identified by the property TZID. For example, iPlanet Calendar Server recognizes the Pacific Standard Time Zone (PST/PDT) as the TZID "America/Los_Angeles". The following time zone defines the "America/Los_Angeles" time zone.

BEGIN:VTIMEZONE

TZID:America/Los_Angeles

BEGIN:STANDARD

DTSTART:19671025T020000

RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10

TZOFFSETFROM:-0700

TZOFFSETTO:-0800

TZNAME:PST

END:STANDARD

BEGIN:DAYLIGHT

DTSTART:19870405T020000

RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4

TZOFFSETFROM:-0800

TZOFFSETTO:-0700

TZNAME:PDT

END:DAYLIGHT

X-NSCP-TZCROSS:19880403T100000Z;19881030T090000Z;19890402T100000Z;19891029T090000Z;

19900401T100000Z;19901028T090000Z;19910407T100000Z;19911027T090000Z;

19920405T100000Z;19921025T090000Z;19930404T100000Z;19931031T090000Z;

19940403T100000Z;19941030T090000Z;19950402T100000Z;19951029T090000Z;

19960407T100000Z;19961027T090000Z;19970406T100000Z;19971026T090000Z;

19980405T100000Z;19981025T090000Z;19990404T100000Z;19991031T090000Z;

20000402T100000Z;20001029T090000Z;20010401T100000Z;20011028T090000Z;

20020407T100000Z;20021027T090000Z;20030406T100000Z;20031026T090000Z;

20040404T100000Z;20041031T090000Z;20050403T100000Z;20051030T090000Z;

20060402T100000Z;20061029T090000Z;20070401T100000Z;20071028T090000Z;

20080406T100000Z;20081026T090000Z;20090405T100000Z;20091025T090000Z;

20100404T100000Z;20101031T090000Z;20110403T100000Z;20111030T090000Z;

20120401T100000Z;20121028T090000Z;20130407T100000Z;20131027T090000Z;

20140406T100000Z;20141026T090000Z;20150405T100000Z;20151025T090000Z;

20160403T100000Z;20161030T090000Z;20170402T100000Z;20171029T090000Z;

20180401T100000Z;20181028T090000Z;20190407T100000Z;20191027T090000Z;

20200405T100000Z;20201025T090000Z;20210404T100000Z;20211031T090000Z;

20220403T100000Z;20221030T090000Z;20230402T100000Z;20231029T090000Z;

20240407T100000Z;20241027T090000Z;20250406T100000Z;20251026T090000Z;

20260405T100000Z;20261025T090000Z;20270404T100000Z;20271031T090000Z;

20280402T100000Z;20281029T090000Z;20290401T100000Z;20291028T090000Z;

20300407T100000Z;20301027T090000Z;20310406T100000Z;20311026T090000Z;

20320404T100000Z;20321031T090000Z;20330403T100000Z;20331030T090000Z;

20340402T100000Z;20341029T090000Z;20350401T100000Z;20351028T090000Z;

20360406T100000Z;20361026T090000Z;20370405T100000Z;20371025T090000Z;

20380404T100000Z;20381031T090000Z;20390403T100000Z;20391030T090000Z

END:VTIMEZONE

Time zones with daylight savings usually contain two parts: STANDARD and DAYLIGHT.

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Note	The "RRULE" property defines the pattern of the STANDARD and DAYLIGHT rules. The "TZOFFSETFROM" and "TZOFFSETTO" properties define the offset from GMT before and after the DAYLIGHT to STANDARD or STANDARD to DAYLIGHT change occurs.

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The "TZNAME" property is an abbreviated representation of the time zone. (The iCalendar Specification provides additional information about the representation of VTIMEZONE.)

Adding a New Time zone

The X-NSCP-TZCROSS property contains a large list of dates that indicate when the time zone crosses over from DAYLIGHT to STANDARD and STANDARD to DAYLIGHT:

• odd number dates indicate STANDARD to DAYLIGHT changes.

• even number dates indicate DAYLIGHT to STANDARD changes.

The Calendar Server's Web browser-based user interface uses the dates in X-NSCP-TZCROSS to signify when to display a change in the time zone.

Use the following steps to add a new time zone to the iPlanet Calendar Server

• Create TZID name not already included in the TZID list.

• Create a representation of the time zone.

• To support the Calendar Web browser user interface, you must generate the X-NSCP-TZCROSS list for the new time zone.

Modifying an Existing Time Zone

To modify an existing time zone:

• Modify a TZID to represent the desired time zone data.

• To support the Calendar Express client, you must generate the X-NSCP-TZCROSS list for the modified time zone.

Customizing Time Zones in the iPlanet Calendar Server User Interface

To modify the Web browser -based user interface to use a customized naming scheme for the time zone, you must add JavaScript code to map the new names to the time zone names supplied with iPlanet Calendar Server.

For example, an administrator who wants to use a customized time zone table called US Pacific instead of the supplied America/Los_Angeles table, must provide a program to map the US Pacific dates to the America /Los_Angeles table.

It is recommended, however, that administrators should not modify the time zone list unless absolutely necessary.

iPlanet Calendar Server Time Zones Table

The iPlanet Calendar Server time zone table is defined in a plain text file called timezones.ics located in the server-root/cal/bin/data directory (for example, opt/SUNWics5/cal/bin/data). It includes 91 time zones based on the JDK (Java Development Kit) version 1.1.

The following example shows the first few sections of the time zone table.

BEGIN:VCALENDAR

BEGIN:VTIMEZONE

TZID:Pacific/Apia

BEGIN:STANDARD

DTSTART:19970101T000000

TZOFFSETFROM:-1100

TZOFFSETTO:-1100

TZNAME:WST

TZNAME:SST

TZNAME:NUT

END:STANDARD

END:VTIMEZONE

BEGIN:VTIMEZONE

TZID:Pacific/Honolulu

BEGIN:STANDARD

DTSTART:19970101T000000

TZOFFSETFROM:-1000

TZOFFSETTO:-1000

TZNAME:HST

TZNAME:TKT

TZNAME:TAHT

END:STANDARD

END:VTIMEZONE

BEGIN:VTIMEZONE

TZID:America/Adak

BEGIN:STANDARD

DTSTART:19671025T020000

RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10

TZOFFSETFROM:-0900

TZOFFSETTO:-1000

TZNAME:HAST

END:STANDARD

BEGIN:DAYLIGHT

DTSTART:19870405T020000

RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4

TZOFFSETFROM:-1000

TZOFFSETTO:-0900

TZNAME:HADT

END:DAYLIGHT

X-NSCP-TZCROSS:19880403T120000Z;19881030T110000Z;19890402T120000Z;19891029T110000Z;

19900401T120000Z;19901028T110000Z;19910407T120000Z;19911027T110000Z;

19920405T120000Z;19921025T110000Z;19930404T120000Z;19931031T110000Z;

19940403T120000Z;19941030T110000Z;19950402T120000Z;19951029T110000Z;

19960407T120000Z;19961027T110000Z;19970406T120000Z;19971026T110000Z;

19980405T120000Z;19981025T110000Z;19990404T120000Z;19991031T110000Z;

20000402T120000Z;20001029T110000Z;20010401T120000Z;20011028T110000Z;

20020407T120000Z;20021027T110000Z;20030406T120000Z;20031026T110000Z;

20040404T120000Z;20041031T110000Z;20050403T120000Z;20051030T110000Z;

20060402T120000Z;20061029T110000Z;20070401T120000Z;20071028T110000Z;

20080406T120000Z;20081026T110000Z;20090405T120000Z;20091025T110000Z;

20100404T120000Z;20101031T110000Z;20110403T120000Z;20111030T110000Z;

20120401T120000Z;20121028T110000Z;20130407T120000Z;20131027T110000Z;

20140406T120000Z;20141026T110000Z;20150405T120000Z;20151025T110000Z;

20160403T120000Z;20161030T110000Z;20170402T120000Z;20171029T110000Z;

20180401T120000Z;20181028T110000Z;20190407T120000Z;20191027T110000Z;

20200405T120000Z;20201025T110000Z;20210404T120000Z;20211031T110000Z;

20220403T120000Z;20221030T110000Z;20230402T120000Z;20231029T110000Z;

20240407T120000Z;20241027T110000Z;20250406T120000Z;20251026T110000Z;

20260405T120000Z;20261025T110000Z;20270404T120000Z;20271031T110000Z;

20280402T120000Z;20281029T110000Z;20290401T120000Z;20291028T110000Z;

20300407T120000Z;20301027T110000Z;20310406T120000Z;20311026T110000Z;

20320404T120000Z;20321031T110000Z;20330403T120000Z;20331030T110000Z;

20340402T120000Z;20341029T110000Z;20350401T120000Z;20351028T110000Z;

20360406T120000Z;20361026T110000Z;20370405T120000Z;20371025T110000Z

END:VTIMEZONE