如何在 PlantUml 中使用 alt-else-end 和手动激活

Question

下面是描述用户如何登录应用程序的序列图：

@startuml
autonumber
actor Individual as individual <<registered>>
boundary "Sign In Page" as signInPage <<ui>>
control "Auth Service" as auth
entity User as user
database Repository as repo

individual -> signInPage ++ : enter username or email
individual -> signInPage : enter password
individual -> signInPage : sign in
signInPage -> auth ++ : auth user
auth -> repo ++ : get user by username or email
return user
auth -> auth ++-- : granted = user exists and credentials are correct
return granted
alt granted is true
autonumber stop
autonumber 9 1
signInPage -> signInPage ++-- : redirect to home page
signInPage --> individual : home page
else granted is false
autonumber stop
autonumber 9 1
signInPage -> signInPage ++-- : redirect to error page
return error page
end
@enduml

上图已正确渲染...

但是

alt

的实现至少是丑陋的。如果授予访问权限，

Sign In Page

应重定向至主页；否则，如果访问被拒绝，

Sign In Page

将重定向到错误页面。正如你所看到的，为了处理手动

activation

，在

alt

部分我必须向

Individual

发回一条消息，而在

else

部分我必须使用

return

语句。有没有更好的方式来表示这一点？

Answer 1

这是基于我对上述问题的评论的答案。

@startuml
'round the notes to look like activity boxes
skinparam roundcorner 10
autonumber
actor Individual as individual <<registered>>
boundary "Sign In Page" as signInPage <<ui>>
control "Auth Service" as auth
entity User as user
database Repository as repo

individual -> signInPage ++ : enter username or email
individual -> signInPage : enter password
individual -> signInPage : sign in
signInPage -> auth ++ : auth user
auth -> repo ++ : get user by username or email
return user
rnote over auth: granted = user exists\nand credentials\nare correct
return granted
rnote over signInPage: page = granted ?\nlogin page :\nerror page
return page
@enduml