JPA - PersistenceUtil.isLoaded Examples

    static void printLoadState(String msg, Employee employee) {
        System.out.printf("-- %s --%n", msg);
        PersistenceUtil pu = Persistence.getPersistenceUtil();
        boolean employeeLoaded = pu.isLoaded(employee);
        System.out.printf("employee loaded: %s%n", employeeLoaded);
        boolean phonesLoaded = pu.isLoaded(employee, "phones");
        System.out.printf("  phones loaded: %s%n", phonesLoaded);
        System.out.println("---------------");
    }

    private static Employee checkAndInitialize(Employee employee) {
        PersistenceUtil pu = entityManagerFactory.getPersistenceUnitUtil();
        System.out.println("       Employee loaded: " + pu.isLoaded(employee));
        System.out.println("Employee.phones loaded: " + pu.isLoaded(employee, "phones"));
        if (!pu.isLoaded(employee) //entity might've been retrieved via getReference
                || !pu.isLoaded(employee, "phones")//phones is a lazy relation
                ) {
            System.out.println("initializing employee");
            boolean detached = !entityManager.contains(employee);
            System.out.println("is employee detached: " + detached);
            if (detached) {
                System.out.println("merging employee");
                employee = entityManager.merge(employee);
            }
            //this will load/initialize employee entity
            employee.getName();
            employee.getDepartment();
            //this will load lazy phones field
            employee.getPhones().size();
            entityManager.detach(employee);
            //now employee is fully initialized
            System.out.println("employee initialized");
        }
        return employee;
    }