Cannot remove values from event stream without breaking pipeline stream

[flomickl]

Body

I tried to remove some values from the stream using the removeFieldBySelector

 event.removeFieldBySelector(latitudeMapper);
 event.removeFieldBySelector(longitudeMapper);

Full code here:

streampipes/streampipes-extensions/streampipes-processors-geo-jvm/src/main/java/org/apache/streampipes/processors/geo/jvm/jts/processor/latlngtojtspoint/LatLngToJtsPointProcessor.java

Line 105 in 8d0aea2

//event.removeFieldBySelector(latitudeMapper);

The values are removed from the stream, but something unknown, strange happens.
The next processor will not receive any events!

Is something wrong with the output strategy???

Workflow and example data can be found here
https://cwiki.apache.org/confluence/x/QZBbDg
and uncomment this lines.

StreamPipes Committer

I acknowledge that I am a maintainer/committer of the Apache StreamPipes project.

[bossenti]

@flomickl this sounds for me more like a discussion
If you don't agree, feel free to revert it to an issue

[flomickl]

so do I have to adjust the output strategy other than .keep() or append() if I use
event.removeFieldBySelector

...
public void onInvocation ...
        .outputStrategy(
            OutputStrategies.append(
                PrimitivePropertyBuilder
                    .create(Datatypes.String, GEOMETRY_RUNTIME)
                    .domainProperty("http://www.opengis.net/ont/geosparql#Geometry")
                    .build()
            )
        )
...

public void onEvent

...
event.removeFieldBySelector(latitudeMapper);
event.removeFieldBySelector(longitudeMapper);
 event.addField(GEOMETRY_RUNTIME, geom.toString());
...