Spring Data Envers custom metadata

Question

I have marked my entity @Audited and I can see that it logs the revision number and timestamp of a new revision, but how can I add custom metadata? I believe it must be possible since org.springframework.data.RevisionMetadata has the getDelegate() method with the following Javadoc:

Returns the underlying revision metadata which might provider more detailed implementation specific information.

Answer 1

From a pure Hibernate Envers perspective, if you want your revision entity to store additional context information about a revision such as who modified the entities or perhaps a reason for the change, then you would want to do this through a RevisionListener callback combined with a custom extension to DefaultRevisionEntity.

For example:

@Entity
@RevisionEntity(CustomRevisionListener.class)
public class CustomRevisionEntity extends DefaultRevisionEntity {
  private String userName;
  /* getter/setters */
}

public class CustomRevisionListener implements RevisionListener {
  @Override
  public void newRevision(Object revisionEntity) {
     CustomRevisionEntity cre = (CustomRevisionEntity)revisionEntity;
     cre.setUserName( UserContextHolder.getUserContext().getUserName() );
  }
}

Envers will detect the special annotated @RevisionEntity entity-class and use it. It will also detect the specified RevisionListener implementation and will instantiate and callback to this class when a new revision entity is constructed.

Unfortunately, I can't speak for how this translates usage-wise with respect towardspring-data and spring-data-envers projects.