[Seaside] [ANN] ICal ocurrences
jbjohns at libsource.com
Wed Nov 1 17:15:49 UTC 2006
I just published a new version of ICal (well a couple, ignore the first
jbjohns) that now supports querying what occurences of an event are
described by a recurrence rule. The public API consists of the
following 6 methods.
ICEvent>>occurrencesBetween: aStartTimeSpan and: anEndTimeSpan
ICEvent>>occurrences: aNumber after: aTimeSpan
ICEvent>>occurrences: aNumber between: aStartTimeSpan and: anEndTimeSpan
The first two require the rule to have a count or until directive, since
otherwise the set would be infinite (I will consider infinite sets later
:) ). All methods are constrained by the rule (i.e. if the rule has a
count directive of 4 then occurrences: 6 will still return only 4). The
ICEvent>>isValidForDate: method was also changed, so that it checks if
the given date is in the set.
Things to be aware of:
Right now the API only works for monthly recurrence rules, but I plan to
put in more soon (I will be focusing on Weekly and above). The rest
will spit out some "does not understand" messages for the occurrence
methods, but otherwise, everything works as before.
Right now the occurrence methods just return an ordered list of dates.
I haven't decided yet what should be returned (just a DateAndTime, or
maybe a complete event representing that day?) so I have just deferred
for now. Let me know what would be the most useful to you.
The classes wont change and the API listed above wont change, but the
methods in the ICFrequency classes will be moved around some.
BUG: If your ICEvent uses multiple rules and they have common dates
between them, they will all be in the returned set (i.e. there can be
multiples of the same date). I am thinking of using some other data
structure then OrderedCollection to fix this problem, and remove the
need for sorting to happen in various spots throughout.
ExclusionRules are not handled at the moment.
The methods are designed for TimeSpan resolution, but right now some of
the lower level methods work on Date's. This should mostly be
transparent, except that the set returned are Date's, instead of
DateAndTime's like they should be. :)
Thanks. Hope this is useful to someone. :)
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