Spring Service - Should I pass an entity Id or the entity itself?

Question

I have a User hibernate entity:

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column
    private String username;

    @Column
    private String password;

    // Getters and setters here
}

If I want to create a UserService method that validates the credentials of a user, should the design of the validate method be like this:

public Boolean validate(Long userId, String username, String password)

or like this:

public Boolean validate(User user, String username, String password)

Which design would be better? Thank you for your time

Answer 1

Your design goal does not make sense to me. The only time you should need a username and a password is during login. At that time, the username and password should uniquely identify a user.

I believe the method you want is this:

publid Optional<User> login(
    final String username,
    final String password);

Then either return an Optional that contains a User (as identified by the correct username and password combination) or return an Optional with null to indentify a bad combination of username and password.

Answer 2

I would create the User's instance with the given username, password and search in the database if the user is exits or not.

Pseudo code:

public booelan validate(User user) {
    userService.findUser(user) != null;
}

You should create the User's instance with the given username, password

User user = new User(userName, password);\\\\I am assuming username should be unique

Then use in your code:

if (isValidate(user)) {
    //doSomething();
}

Answer 3

You can simply add a method in your UserRepository :

    User findByIdAndUsernameAndPassword(long id, String userName, String pass);

This will return a User if all of these fields match with a specific database entry.

Passing entityId is better , I hope this addresses what you were asking.