Ok, thanks for the clarification Till. On Wed, Apr 20, 2016 at 4:46 PM, Till Rohrmann <trohrm...@apache.org> wrote:
> You could use CEP for that. First you would create a pattern of two states > which matches everything. In the select function you could then check > whether both elements are different. > > However, this would be a little bit of an overkill for this simple use > case. You could for example simply use a flat map operation which stores > the last seen element. Then whenever you see a different element you can > emit a change event. > > Cheers, > Till > > On Wed, Apr 20, 2016 at 2:43 PM, Stefano Baghino < > stefano.bagh...@radicalbit.io> wrote: > >> Can the CEP library be used for this use case? >> >> On Wed, Apr 20, 2016 at 2:02 PM, Aljoscha Krettek <aljos...@apache.org> >> wrote: >> >>> Hi, >>> this could be done by implementing a user function that keeps state or >>> by using windows with a custom Trigger. On only works, however, if you only >>> have one Kafka partition and if your Flink job is executing with >>> parallelism=1. Otherwise we don't have any ordering guarantees on streams. >>> >>> Cheers, >>> Aljoscha >>> >>> On Wed, 20 Apr 2016 at 12:50 <tole...@toletum.org> wrote: >>> >>>> Hi! I'm a beginner in Flink. >>>> I'm reading from a Kafka topic. In this topic, I receive a character >>>> each event, like that: >>>> >>>> Event.: 1 2 3 4 5 6 7 8 9... >>>> Data..: A A A B B B B C C... >>>> >>>> I would like to do a "trigger" when the character is different than >>>> before. For example: >>>> Event º1 fire because of A is different to "null" >>>> Event º4 fire because of B is different to A >>>> Event º8 fire because of C is different to B >>>> >>>> Could it be possible? >>>> >>> >> >> >> -- >> BR, >> Stefano Baghino >> >> Software Engineer @ Radicalbit >> > > -- BR, Stefano Baghino Software Engineer @ Radicalbit
