Is it possible to use systemd socket activation with librespot-java?

[GeorgeHJ]

Currently I have a systemd user unit for librespot-java which pretty much just runs a wrapper shell script.

My question was, whether there's a particular way to have systemd listen for something like the official Spotify client or spotify-tui so that the back-end is only running when there's a controller for it?

[zugazagoitia]

AFAIK you can do it through systemd if they are also a Unit, using Wants or Requires. You could also code that logic into the wrapper script.