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3.8.5.2. Recurrence Date-Times

Property Name

RDATE

Purpose

This property defines the list of DATE-TIME values forrecurring events, to-dos, journal entries, or time zonedefinitions.

Value Type

The default value type for this property is DATE-TIME.The value type can be set to DATE or PERIOD.

Property Parameters

IANA, non-standard, value data type, and timezone identifier property parameters can be specified on thisproperty.

Conformance

This property can be specified in recurring"VEVENT","VTODO", and"VJOURNAL" calendar components as well as in the"STANDARD" and "DAYLIGHT" sub-components of the"VTIMEZONE"calendar component.

Description

This property can appear along with the"RRULE"property to define an aggregate set of repeating occurrences.When they both appear in a recurring component, the recurrenceinstances are defined by the union of occurrences defined by boththe"RDATE" and"RRULE".

The recurrence dates, if specified, are used in computing therecurrence set. The recurrence set is the complete set ofrecurrence instances for a calendar component. The recurrence setis generated by considering the initial"DTSTART" property alongwith the"RRULE","RDATE", and"EXDATE" properties containedwithin the recurring component. The"DTSTART" property definesthe first instance in the recurrence set. The"DTSTART" propertyvalue SHOULD match the pattern of the recurrence rule, ifspecified. The recurrence set generated with a"DTSTART" propertyvalue that doesn't match the pattern of the rule is undefined.The final recurrence set is generated by gathering all of thestart DATE-TIME values generated by any of the specified"RRULE"and"RDATE" properties, and then excluding any start DATE-TIMEvalues specified by"EXDATE" properties. This implies that startDATE-TIME values specified by"EXDATE" properties take precedenceover those specified by inclusion properties (i.e.,"RDATE" and"RRULE"). Where duplicate instances are generated by the"RRULE"and"RDATE" properties, only one recurrence is considered.Duplicate instances are ignored.

Format Definition

This property is defined by the followingnotation:

 rdate      ="RDATE" rdtparam ":" rdtval *("," rdtval) CRLF

 rdtparam   = *(            ;            ; The following are OPTIONAL,            ; but MUST NOT occur more than once.            ;            (";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) /            (";" tzidparam) /            ;            ; The following is OPTIONAL,            ; and MAY occur more than once.            ;            (";" other-param)            ;            )

 rdtval     = date-time / date / period ;Value MUST match value type

Example

The following are examples of this property

 RDATE:19970714T123000Z RDATE;TZID=America/New_York:19970714T083000

 RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,  19960404T010000Z/PT3H

 RDATE;VALUE=DATE:19970101,19970120,19970217,19970421  19970526,19970704,19970901,19971014,19971128,19971129,19971225

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