Does QuickFIX/J provide any way to specify field->values mappings in config files that should be used on specific sessions?
For example on SESSION_UAT I want to send on every NewOrder customTag1="Test", and on SESSION_PROD I want customTag1="Real"? The values may change over time and should be maintained by non-developers so I don't want to do that part in code.
I could myself add support for this but I wonder if there's anything like that already so I won't reinvent the wheel. I was looking at codegen package in QuickFIX/J for this but the code generating step is something I want to avoid.
No, this is not something that QF/j explicitly offers.
However, you could put a custom value in the QF/j session config file (see docs) and set your value according to that. That's a pretty easy way to do it.
Or if you don't want users to be able to edit the session config, it would be simple to roll your own config file format and reader.