@startuml
Client -> Subject
Subject <|- RealSubject
Subject <|-- Proxy
RealSubject <--o Proxy

interface Subject {
  {abstract} +Request()
}
class RealSubject {
  +Request()
}

class Proxy {
  -aRealSubject
  +Request()
}
note right of Proxy
  Proxy::Request() {
    aRealSubject.Request();
  }
end note

hide empty attributes
hide empty methods
@enduml