Simpler service interfaces with Guice

I'm using Guice throughout my code, and I've found a pattern that works rather nicely. Suppose I've got a service interface method for scheduling a delivery:

public interface DeliveryService {
  /**
   * Schedules {@link order} for delivery and returns a snapshot with
   * the details of the scheduled delivery.
   *
   * @param loggedInUser the customer service rep who is making this request.
   * @param selectedCustomer the customer to whom the order will be delivered
   * @param order the order to schedule a delivery for
   */
  Delivery scheduleDelivery(User loggedInUser, 
      Customer selectedCustomer, Order order);
}`</pre>The interface does exactly what it needs to do. But since it has so many parameters, calling it is a hassle for the caller. They need to inject the user and customer, only to pass it to the service:
<pre class="prettyprint">public class ScheduleDeliveryAction implements Action {
  private final DeliveryService deliveryService;
  private final User loggedInUser;
  private final Customer selectedCustomer;
  private Delivery delivery;

  @Inject
  public ScheduleDeliveryAction(DeliveryService deliveryService,
      User loggedInUser, Customer selectedCustomer) {
    this.deliveryService = deliveryService;
    this.loggedInUser = loggedInUser;
    this.selectedCustomer = selectedCustomer;
  }

  public String execute() {
    /* parse HTTP parameters etc. */
    Order order = ...

    this.delivery = deliveryService.scheduleDelivery(
        loggedInUser, selectedCustomer, order);

    return SUCCESS;
  }

  ...
}</pre>

### A better approach

A better approach is have the service know about the logged in user and customer implicitly. I change the real implementation of the service so that it gets the Customer and User injected into it. Now the interface is simpler:
<pre class="prettyprint">`public interface DeliveryService {
  /**
   * Schedules {@link order} for delivery and returns a snapshot with
   * the details of the scheduled delivery.
   *
   * @param order the order to schedule a delivery for
   */
  Delivery scheduleDelivery(Order order);
}

And so is the calling code:

public class ScheduleDeliveryAction implements Action {
  private final DeliveryService deliveryService;
  private Delivery delivery;

  @Inject
  public ScheduleDeliveryAction(DeliveryService deliveryService) {
    this.deliveryService = deliveryService;
  }

  public String execute() {
    /* parse HTTP parameters etc. */
    Order order = ...

    this.delivery = deliveryService.scheduleDelivery(order);

    return SUCCESS;
  }

  ...
}