flink-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Yassine MARZOUGUI <y.marzou...@mindlytix.com>
Subject Re: notNext() and next(negation) not yielding same output in Flink CEP
Date Mon, 24 Jul 2017 08:40:56 GMT
Hi Dawid,

Thanks a lot for the explanation, it's all clear now.

Best,
Yassine

2017-07-23 13:11 GMT+02:00 Dawid Wysakowicz <wysakowicz.dawid@gmail.com>:

> Hi Yassine,
>
> First of all notNext(A) is not equal to next(not A). notNext should be
> considered as a “stopCondition” which tells if an event matching the A
> condition occurs the current partial match is discarded. The next(not A) on
> the other hand accepts every event that do not match the A condition.
>
> So let’s analyze a sequence of events like “b c a1 a2 a3 d”. For the first
> version with next(not A) the output will be “c a1 a2 a3 d” which is what
> you expect, I think. In the other version with notNext(A) a partial match
> “c a1” will be discarded after “a2” as the notNext says that after the A’s
> there should be no A.
>
> I hope this helps understanding how notNext works.
>
> Regards,
> Dawid
>
> > On 22 Jul 2017, at 20:32, Yassine MARZOUGUI <y.marzougui@mindlytix.com>
> wrote:
> >
> > Hi all,
> >
> > I would like to match the maximal consecutive sequences of events of
> type A in a stream.
> > I'm using the following :
> > Pattern.begin("start").where(event is not A)
> > .next("middle").where(event is A).oneOrMore().consecutive()
> > .next("not").where(event is not A)
> > I This give the output I want. However if I use
> notNext("not").where(event is A) instead of next("not").where(event is not
> A), the middle patterns contain only sequences of single elements of type A.
> > My understaning is that notNext() in this case is equivalent to
> next(negation), so why is the output different?
> >
> > Thank you in advance.
> >
> > Best,
> > Yassine
>
>

Mime
View raw message