取决于.如果您有一个负责发送电子邮件的系统-可以将其称为NOTIFY-而另一个系统-可以将其称为X-使用NOTIFY，则可以将X建模为用例的参与者发送包含以下内容的电子邮件通知.另一方面，不能使用自己的用例将NOTIFY本身建模为参与者.

Depends. If you have a system that is responsible for sending e-mails - lets call it NOTIFY - and another system - lets call it X - that uses NOTIFY then X can be modelled as an actor of use case Send e-mail that is covered by NOTIFY. On the other hand, NOTIFY itself cannot be modelled as an actor using its own use cases.