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Exit pattern matching

Hi Flink Team,

First, I would like to thank for such a wonderful tool and appreciate your
I am developing an application where I am processing stream of geolocations
and detecting geofence if exactly 3 events are inside geofence. The code is
something like this:-

Pattern<KafkaLocationEvent, ?> geofencePattern =
                .where(new IterativeCondition<KafkaLocationEvent>() {

                    private static final long serialVersionUID = 1L;

                    public boolean filter(KafkaLocationEvent value,
Context<KafkaLocationEvent> ctx) throws Exception {
                        return distanceInMts < geofenceRadiusInMts;

                 PatternStream<KafkaTaskEvent> tempPatternStream =
CEP.pattern(messageStream, geofencePattern);

                 // select matching patterns and generate alerts
                    DataStream<String> alerts =
tempPatternStream.select(new GeofenceAlertPatternSelectFunction());

The issue is that alerts are generated even if I get 4th event inside
geofence and so on. I just want to generate alert once at the first pattern
match and exit the pattern after that.

As per docs, I am not able to find a relevant function I can use to do
this. Please help.
Thanks in Advance.


*Moiz Motorwala*