Thanks a lot for your PR and especially adding also a test!

What I'm not so sure about is the fetchField in the builder. Don't you think it would be better just to set the DataFetcher instead having extra field? This also doesn't scale very well: Imagine we add a third or fourth provided DataFetcher.

What do you think?

Thanks

Yeah, the builder methods aren't necessary. However, I liked the way you don't have to specify the name of the property twice. It removes a failure possibility.
Another option would be to have a "DataFetcherStrategy" field in the builder containing an enum. It would default to "Property", but could be set to "Field". If more provided DataFetcher's are added they would be represented by additional enums.

Yes, you are right. Not having to specify the name twice is a good thing. I will merge this now. But probably I will change it to something more generic like your suggested "DataFetcherStrategy" field to make it more stable for other DataFetchers in the future.

Thanks again,
Andi