Thanks Till, At the end, I'm going to use a countWindowAll(2,1) and RichAllWindowFunction.
Regards, On mié., abr. 20, 2016 at 16:46, Till Rohrmann 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 wrote: Can the CEP library be used for this use case? On Wed, Apr 20, 2016 at 2:02 PM, Aljoscha Krettek 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 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
