Property Name

RDATE

Purpose

This property defines the list of DATE-TIME values for recurring events, to-dos, journal entries, or time zone definitions.

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 time zone identifier property parameters can be specified on this property.

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 recurrence instances are defined by the union of occurrences defined by both the "RDATE" and "RRULE".

The recurrence dates, if specified, are used in computing the recurrence set. The recurrence set is the complete set of recurrence instances for a calendar component. The recurrence set is generated by considering the initial "DTSTART" property along with the "RRULE", "RDATE", and "EXDATE" properties contained within the recurring component. The "DTSTART" property defines the first instance in the recurrence set. The "DTSTART" property value SHOULD match the pattern of the recurrence rule, if specified. The recurrence set generated with a "DTSTART" property value that doesn't match the pattern of the rule is undefined. The final recurrence set is generated by gathering all of the start DATE-TIME values generated by any of the specified "RRULE" and "RDATE" properties, and then excluding any start DATE-TIME values specified by "EXDATE" properties. This implies that start DATE-TIME values specified by "EXDATE" properties take precedence over 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 following notation:

 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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