Hi, So yes you can do it with IterativeConditions.
Cheers, Kostas > On Mar 1, 2018, at 1:15 PM, Esa Heikkinen <esa.heikki...@student.tut.fi> > wrote: > > > Hi > > 6) I meant that in the first step the CEP pattern queries value for “Id” and > stores the value to (global) variable for later use in the same pattern or > even other places in the application. Is this possible ? > > Best, Esa > > From: Kostas Kloudas [mailto:k.klou...@data-artisans.com] > Sent: Thursday, March 1, 2018 11:35 AM > To: Esa Heikkinen <esa.heikki...@student.tut.fi> > Cc: user@flink.apache.org > Subject: Re: Questions about the FlinkCEP > > Hi Esa, > > The answers to the questions are inlined. > > > On Feb 28, 2018, at 8:32 PM, Esa Heikkinen <heikk...@student.tut.fi > <mailto:heikk...@student.tut.fi>> wrote: > > Hi > > I have tried to learn FlinkCEP [1], but i have yet not found the clear > answers for questions: > 1) Whether the pattern of CEP is meant only for one data stream at the same > time ? > Yes. > > 2) If i have many different parallel data streams (or sources), should i > combine them into one data stream (and is this possible ?), if i want to use > same CEP pattern for all parallel streams at the same time ? > > Yes you should somehow combine them. This can be done with .union if this is > ok for you logic but > how to do it depends on your job. Or you can just apply the same pattern to > all your streams and then > union the result into a single output stream. > > > 3) What is the format of data stream of events for CEP ? > > The input can be an arbitrary data stream. > > https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/libs/cep.html > <https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/libs/cep.html> > https://flink.apache.org/news/2016/04/06/cep-monitoring.html > <https://flink.apache.org/news/2016/04/06/cep-monitoring.html> > https://data-artisans.com/blog/complex-event-processing-flink-cep-update > <https://data-artisans.com/blog/complex-event-processing-flink-cep-update> > > > > 4) Can i directly supply a data stream from env.socketTextStream() to CEP ? > > Yes. Why don’t you try it out ;) > > > 5) Can one event in stream include many "attributes" and values ? Or is it > only key-value-pair ? Timestamp of event ? > > An event can have arbitrary format. It is up to you to interpret your data. > > > 6) Can CEP save the found values of events for use in later "steps" ? For > example in pattern: > > val pattern = Pattern.begin("start").where(_.getId == 42) > > > .next("middle").subtype(classOf[SubEvent]).where(_.getVolume >= 10.0) > > > .followedBy("end").where(_.getName == "end") > Whether value of Id in"start"-step can be saved and check whether it (Id) is > same in "end"-step ? > > > If I get the question right, you can do it with Iterative conditions, as > described in the documentation. > > > [1] > https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/libs/cep.html > <https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/libs/cep.html> > > Best, Esa > > Best, > Kostas >
