I've got something in the works with @Value.

But I also realized that there could be more to it, i.e. 
1) there is the human friendly description (/tmp/xd/tmp/\<streamname/>)
2) there is the actual expression (/tmp/xd/tmp/${xd.stream.name})
3) there is early vs. late binding (xd.stream.name is not available until stream creation, whereas say "default.redis.port" is)