I have the following JPA entity hierarchy:
Upon logging in to the application a user has an instance of UserAccount in session; then depending on the concrete type of the organization associated to that UserAccount (Admin, Business or Family), a different dashboard/screen is displayed to the user e.g. if the user is a Business, then the dashboard for that business is displayed.
My concern with that design is that I have to do a instanceof check each time a user logs in so that I know which type of dashboard to display. I could also avoid that instanceof check by having a property in UserAccount such as organizationType (which would take one of three values) but then there would be redundant information.
Is there a way to improve my design? If so how?
1 Answers
Answers 1
Be greedy and get both, without redundancy.
Depending on the inheritance strategy, you may already have the organizationType info and you can expose it for free.
@Entity @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name = "DTYPE") public abstract class AbstractOrganization implements Serializable { @Id protected Long id; @Column(name = "DTYPE", insertable = false, updatable = false) protected String organizationType; ... } the same applies also to the JOINED strategy.
Do not implement the setOrganizationType method.
Since a discriminator is required for simulating hierarchies with tables (except TABLE_PER_CLASS strategy), there's no redundancy and JPA provider will handle this attribute for you.
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