Scala 在sangria graphql中面临订阅问题

Scala 在sangria graphql中面临订阅问题,scala,graphql,subscription,sangria,Scala,Graphql,Subscription,Sangria,我需要在sangria进行订阅工作。我浏览了文档并尝试实现它,但在理解它时我面临很多问题 val SubscriptionType = ObjectType("Subscription", fields[Unit, Unit]( Field.subs("userEvents", UserEventType, resolve = _ ⇒ Observable(UserCreated(1, "Bob"), UserNameChanged(1, "John")).map(action(_)

我需要在sangria进行订阅工作。我浏览了文档并尝试实现它,但在理解它时我面临很多问题

val SubscriptionType = ObjectType("Subscription", fields[Unit, Unit](
  Field.subs("userEvents", UserEventType, resolve = _ ⇒
    Observable(UserCreated(1, "Bob"), UserNameChanged(1, "John")).map(action(_))),

  Field.subs("messageEvents", MessageEventType, resolve = _ ⇒
    Observable(MessagePosted(userId = 20, text = "Hello!")).map(action(_)))
))
我无法理解什么是UserCreated、UserNameChanged或messagepost。它们是写入数据库查询的方法。谁能帮我理解这一点

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