Update a certain field of an entity everytime before calling save()-CodePudding

So I have three entites. A, B and P (P is superclass). This is how they look like:

@MappedSuperclass
public class P {

    @Id
    @GeneratedValue
    protected Long id;

    protected LocalDateTime lastUpdated = LocalDateTime.now();
   
  //Other fileds, getters, setters, etc...
 
}

@Entity
@Table
public class A extends P {

  //fileds, getters, setters, etc..
 
}

@Entity
@Table
public class B extends P {

  //fileds, getters, setters, etc..
 
}

And I have repositories for both entities A and B

@Repository
public interface ARepository extends JpaRepository<A, Long> {

}

B repository

@Repository
public interface BRepository extends JpaRepository<B, Long> {

}

When I save an entity, I have to update the field lastUpdated by calling the setter method before save() everytime like so:

@Service
public class AService {
  
    private final ARepository aRepository;

    @Autowired
    public AService(ARepository aRepository){
        this.aRepository= aRepository;
    }

    public A doSomethingToA(A a){
        //Run some logic here...
        a.setLastUpdated(LocalDateTime.now()); // I dont want this line one very update method of every entity. is there a way to put it inside the save() method (overriding or something), or any other solution to this?
        return aRepository.save(a);
    }
}

The problem here is that if I have 200 entities that extend the class P, I have to call this setLastUpdated() method everytime before calling save(). Is there anyway I can put this line inside of the save method? (without having to override save on all 200 repositories of the 200 entites that extend P).

CodePudding user response：

You could use Hibernate's EntityListener on your class P :

public class P {

    @PreUpdate
    @PrePersist
    public void setLastUpdated() {
       lastUpdated = LocalDateTime.now();
    }
}

Official documentation about it : https://docs.jboss.org/hibernate/stable/entitymanager/reference/en/html/listeners.html