Spring Data MongoDB - Is there a way to have an implicit timestamp? - mongodb

Question

Using my MongoDB and Spring Data MongoDB I am currently looking for a timestamp to be visible in the collection documents.
For now the document looks like this:
{
"_id":"f84fd693-e04b-4acb-9390-32ee755c1506",
"name":"Herbert",
"age":{"$numberInt":"21"},
"_class":"com.alemannigame.backend.domain.Character"
}
However I'd like to have a "timestamp": "1988-03-12T02:30:12+00:00" (example format) in it as well. Is there a way to do so without having to write logic in a Service to actually add a timestamp manually?
I thought about something like:
#Document(withTimestamp: true) // this
data class Character(
#Id
val id: String,
val name: String,
val age: Int
)
Could not find anything similar in the interwebs! Nifty solutions are welcome!

Answer 1

So I found something out about Lifecycle Events for Spring Data MongoDB (https://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#mongo.aggregation).
This gave me several interceptors before a document is saved to MongoDB.
It's very straight forward to use. I chose the onBeforeConvert hook so I can manipulate my model before it is being saved.
As you can see I added the timestamp of the event to my source instance. I like Unix timestamps and since the event object already has that ready I reused it.
#Component
class MongoSaveInterceptor : AbstractMongoEventListener<Character>() {
override fun onBeforeConvert(event: BeforeConvertEvent<Character>) {
val source = event.source
source.timestamp = event.timestamp
}
}
When using MongoDB's implicit ObjectId (which I do not - I use an own UUID id) I think that event.timestamp is used here.