How to write dynamic attribute names ?

Hi All,

I'm trying to create and write dynamic attribute name with the joined workspace.

In a FFS file, I have C-SEGMT entities. I would like to count how any entities I have until the current year (e.g. 2023) but also for the two previous years (e.g. 2022 and 2021) and put the result in a dynamic attribute name (for my example, three attributes named "NumEntities__2023", "NumEntities__2022" and "NumEntities__2021"

I can create them, as you can see it in my Workbench and the screen capture, but I don't know how to write them in my Writer. It's OK for a FFS Writer, but if I want to write in a GEOJson file or other formats, it fails.

I could name them directly "NumEntities__2023", "NumEntities__2022", "NumEntities__2021" ; or I could expose them with AttributeExposer : I can see their name if I have enabled feature caching. But my goal is, if I run the workbench next year, the attributes will be automatically renamed "NumEntities__2024", "NumEntities__2023", "NumEntities__2022".

Does anyone has any idea ? The attributes must be in the same file and same FeatureType, so I can't use the fanout option (but maybe I have used it wrong). Published Parameter ?

Many thanks !

Have a good day