I am developing a system with Java EE and JPA where users can make changes to entities. It is needed to trace back to the changes when needed. So the all the changes and the user have to be recorded for each occasion when en update is made. What is the best way to record the changes.
For example, there is an Entity called Investigation. It has attributes like Name, Category, Price, Volume, etc. A user can search a single investigation and change the name in one instance and in another instance, another user can change the price. All these occasions with the change done and the user who did it is needed to be traced back when needed.
One method described in this link is that to label objects as old edited and create a new object with updated values, but the problem there are several other objects from different entities referring to the old one.
Another method as described in this link is to use a versioning field in a new table. Than can be achieved in JPA by creating a new entity that extends the main entity.
Out of these methods what is the best practice? Is there any other optimized way to keep the record editing history in Java Persistence?
EclipseLink supports history.
See, http://wiki.eclipse.org/EclipseLink/Examples/JPA/History
If you don't mind using Hibernate, Envers might be interesting for you. It performs auditing automatically, optionally appending metadata like current user.
For each audited entity it creates a history table that holds previous versions.
you could have a look at the usage of interceptors to intercept the calls to your bean which saves the data into the database. Within this interceptor you could inject the current SessionContext and read the current user out of it... than you could set this users as the entities "modifiedBy" String or whatever.
I didnt read it thoroughly, but by skimming through it might help you: http://kenai.com/projects/javaee-patterns/forums/forum/topics/3191-Adding-current-user-information-to-JPA-entities
