Hi Elias, Glad that this is not a blocker for you and you are right that we should clarify it better in the documentation.
Thanks, Kostas > On Apr 27, 2017, at 3:28 AM, Elias Levy <fearsome.lucid...@gmail.com> wrote: > > You are correct. Apologies for the confusion. Given that > ctx.getEventsForPattern returns an iterator instead of a value and that the > example in the documentation deals with summing multiple matches, I got the > impression that the call would return all previous matches instead of one at > a time for each branch. > > I suppose it returns an iterator to support patterns where the event has some > associated enumerator, like times(), zeroOrMore(), or oneOrMore(), yes? > > Might be helpful to clarify this and point out that the iterator will contain > a single value for the common case of match with a enumerator of one, which > is the default. > > > On Wed, Apr 26, 2017 at 2:15 AM, Kostas Kloudas <k.klou...@data-artisans.com > <mailto:k.klou...@data-artisans.com>> wrote: > Hi Elias, > > If I understand correctly your use case, you want for an input: > > event_1 = (type=1, value_a=K, value_b=X) > event_2 = (type=2, value_a=K, value_b=X) > event_3 = (type=1, value_a=K, value_b=Y) > > to get a match: > > event_1, event_2 > > and discard event_3, right? > > In this case, Dawid is correct and from a first look at your code, it should > work. > If not, what is the output that you get? > > Kostas > > >> On Apr 26, 2017, at 8:39 AM, Dawid Wysakowicz <wysakowicz.da...@gmail.com >> <mailto:wysakowicz.da...@gmail.com>> wrote: >> >> Hi Elias, >> >> You can do it with 1.3 and IterativeConditions. Method >> ctx.getEventsForPattern("foo") returns only those events that were matched >> in "foo" pattern in that particular branch. >> I mean that for a sequence like (type =1, value_b = X); (type=1, value_b=Y); >> (type=2, value_b=X) both events of type = 1 create a seperate pattern branch >> and the event with type = 2 will be checked for a match twice for both of >> those branches. >> >> Regards, >> Dawid >> >> 2017-04-26 7:48 GMT+02:00 Elias Levy <fearsome.lucid...@gmail.com >> <mailto:fearsome.lucid...@gmail.com>>: >> There doesn't appear to be a way to join events across conditions using the >> CEP library. >> >> Consider events of the form (type, value_a, value_b) on a stream keyed by >> the value_a field. >> >> Under 1.2 you can create a pattern that for a given value_a, as specified by >> the stream key, there is a match if an event of type 1 is followed by an >> event of type 2 (e.g. >> begin("foo").where(_.type==1).followedBy("bar").where(_.type==2). But this >> will return a match regardless of whether value_b in the first event matches >> value_b in the second event. >> >> 1.3 snapshot introduces iterative conditions, but this is insufficient. In >> 1.3 you can do: >> >> begin("foo").where(_.type==1).followedBy("bar").where( >> (v, ctx) => { >> v.type == 2 && >> ctx.getEventsForPattern("foo").asScala.exists(prev => prev.value_b == >> v.value_b) >> }) >> >> This will accept the current event if any if any previously had a value_b >> that matches the current event. But the matches will include all previous >> events, even those that did not match the current event at value_b, instead >> of only matching the previous event where value_b equals the current event. >> >> Is there a way to only output the match there previous event matches the >> current event value_b (e.g. foo == (type=1, value_a=K, value_b=X) and bar == >> (type=2, value_a=K, value_b=X)? >> >> >> > >
