Does anyone have a working example of "AbstractMongoEvent for Spring MongoDB cascade save on DBRef?

Question

Java

Hello,
do you want to organize "cascade save" for yourself in mongodb or not bother, but save objects one by one?
mongdb - 3.4.2
The only good example found - not very working onBeforeConvert - looks different now.
https://www.javacodegeeks.com/2013/11/spring-data-...
Nothing unusual, just one object has @DBRef on another, I would like to save them in one fell swoop.
Thank you!