Spring Data MongoDB BeforeSaveCallback not working - spring

Question

I want to have similar functionality as I get with the JPA #PrePersist but in a mongodb database. Reading the spring data mongodb documentation I found the entity callbacks: https://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#entity-callbacks. They seem to work for what I need so I'm trying to implement some callbacks. I know there are some alternatives for what I'm doing (auditing annotations) but I want to keep with this for the moment.
This is how I register the callback, my entity definition and the repository:
#Configuration
public class BeforeSaveCallbackConfiguration {
#Bean
BeforeSaveCallback<Measurement> beforeSaveMeasurement() {
return (entity, document, collection) -> {
entity.setTimestamp(System.currentTimeMillis());
System.out.println("Before save, timestamp: " + entity.getTimestamp());
return entity;
};
}
}
public interface MeasurementRepository extends MongoRepository<Measurement, String> {
}
#Document
public class Measurement {
private String id;
private long timestamp;
private Float value1;
private Float value2;
// constructor, getters, setters ...
}
I save the entity using measurementRepository.save method of the repository. I actually see the printed line from the callback with the timestamp. However the data saved in the mongodb collection always have timestamp set to 0. Does anyone have any hint?

Answer 1

You implement BeforeConvertCallback interface can work for you：
#Component
public class TestCallBackImpl implements BeforeConvertCallback<Measurement> {
#Override
public Measurement onBeforeConvert(Measurement entity, String collection) {
entity.setTimestamp(System.currentTimeMillis());
return entity;
}
}