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>
> 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)?
>
>
>
