@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
abstract class Token : ResourceSupport {
    @Id
    @GeneratedValue(generator="gen")
    @GenericGenerator(name="gen", strategy="foreign", parameters= [Parameter(name = "property", value = "user")])
    var id: Int? = null

    @Column(name = "token", unique = true)
    var token: String? = null

    @Column(name = "expirationDate")
    var expirationDate = setDefaultExpirationDate()

    @OneToOne
    @PrimaryKeyJoinColumn
    var user: User? = null
}