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iCal4j Extensions - Concept

The iCalendar property CONCEPT was recently ratified as a standard way to classify iCalendar objects. These extensions provide some suggested classifications that represent common use-cases for different types of iCalendar objects.


The following iCal4j concepts are derived from the different structural patterns used to support different use-cases for iCalendar objects.

These concepts include:

  • Event - an opaque VEVENT object that may support recurrences.
  • Observance - a transparent VEVENT object that may support recurrences.
  • Action - a VTODO object that is assignable to individuals for resolution. Supports recurrences.
  • Issue - a VTODO object capturing a one-off impediment to other activities or actors. Does not support recurrences.
  • Request - a VTODO object representing a service request, often fulfilled via an Action. May support recurrences.
  • Note - a VJOURNAL object capturing a note or annotation related to other activities or entities. Does not support recurrences.
  • Metric - a VJOURNAL object used to measure past activities or entities. Supports recurrences.
  • Availability - a VAVAILABILITY object that defines availability of an intangible or tangible resource. Supports recurrences.