How do I use the Projection Processor in SAM?

[#1]

I want to use the Projection Processor in my Streaming Analytics App to concatenate 2 fields of a data stream, so I can use both of them in a join processor. When I try to use the Projection processor, though, and I enter the projection fields and CONCAT-function and the right arguments and a field name, and then I press Ok and re-enter the processor, it is completely empty again. So how do I use the processor in a way that it doesn't reset all the time? Or is there a workaround to use 2 fields on a join processor?

EDIT: I am using HDF 3.0.2.0-76

[#2]

I found a work-around using NiFi: I use NiFi to add additional info to the content of the flow file and I updated the Schema Registry to reflect this, to then Join over the new value in the field "SignalID" as I called it.

[#3]

you could write your own User defined processor also.

[#4]

The above question and the entire response thread below were originally posted in the Community Help track. On Mon Jul 22 15:13 UTC 2019, a member of the HCC moderation staff moved it to the Data Ingestion & Streaming track. The Community Help Track is intended for questions about using the HCC site itself.