Mapping calculated properties with JPA

Question

Is there a way to map a calculated property using JPA?

Assuming I have an Invoice object with one or more InvoiceLineItems within it, I wan

Answer 1

What you've described is not a calculated property in JPA sense. You're calculating it yourself within your method - just mark that method as @Transient and JPA will ignore it.

If you truly need a calculated property (where "calculated" means "calculated via SQL expression"), you'll need to annotate it according to your JPA provider. For Hibernate you'd do that via @Formula annotation:

@Formula("col1 * col2")
public int getValue() {
 ...
}

Other providers may have their own ways to configure this; there's no JPA standard.