uml - 用例图中的参与者

Question

我对我的演员在我的用例图中应该是什么感到很困惑。

例如，下面是处理在线商店运输订单的子系统的用例。我不明白这些演员应该是什么。只是系统在幕后做这些事情。在我看来，它们不是由某种外部输入触发的。

我在这里想念什么？

Answer 1

My thoughts on this:

• "Ship order" as the subsystem name sounds confusing to me. It would probably be clearer to call it "Order shipping service" or something similar.
• "Ship order" could be the main use case within this subsystem (as commented by www.admiraalit.nl). You may want to model the other activites as use cases as well and link them to your main use case using include relations. However, this makes sense only if you want to reuse them (e.g. include them in more than one use case) or if they can be invoked directly by an actor. For instance, "assign driver" or "create delivery schedule" might be called separately to change these things after the order has been handed over to delivery.
• The actor triggering your use case(s) would either be an operator who decides that an order is ready for shipment or another subsystem if this happens automatically.