@Service(CustomerService.NAME)
public class CustomerServiceBean implements CustomerService {


	  @Inject
	    private Persistence persistence;

	    @Inject
	    private Metadata metadata;


	@Override
	public void createOrUpdateCustomer(String name, String email) {
		 try (Transaction tx = persistence.createTransaction()) {
	            // Search for existing customers with the given name
	            TypedQuery<Customer> query = persistence.getEntityManager().createQuery(
	                    "select c from sales$Customer c where c.name = :name", Customer.class);
	            query.setParameter("name", name);
	            List<Customer> customers = query.getResultList();
	            if (customers.size() == 0) {
	                // no customer with the given name, creating it
	                Customer customer = metadata.create(Customer.class);
	                customer.setName(name);
	                customer.setEmail(email);
	                // persist the new instance
	                persistence.getEntityManager().persist(customer);
	            } else if (customers.size() == 1) {
	                // a customer found, updating it
	                Customer customer = customers.get(0);
	                customer.setEmail(email);
	                // the loaded customer is in Managed state and will be saved to the database on transaction commit
	            } else {
	                // more than one customer found, raising an error
	                throw new IllegalStateException("More than one customer with name " + name);
	            }
	            tx.commit();
		 }
	}

}