@startuml
title Alternative D: Event-based notification between RouDi and User App

participant RouDi
participant UserAppA
participant UserAppB

activate UserAppA

UserAppA->UserAppA: DiscoveryInfo::DiscoveryInfo()
UserAppA->RouDi:  getMiddlewareSubscriber() / CREATE_Subscriber

RouDi->UserAppA: CREATE_SUBSCRIBER_ACK
deactivate UserAppA

UserAppA->UserAppA: Listener::attachEvent(discoveryInfo)


UserAppA->UserAppA: Listener::wait()
activate UserAppA
note right: Only react on CaproMessageSubType::SERVICE

UserAppB->RouDi: offer()
loop every 100ms
    RouDi->RouDi: doDiscovery()

    activate RouDi
    RouDi->RouDi: doDiscoveryForPublisherPorts()
    alt CaproMessage received
        RouDi->RouDi: sendToAllMatchingInterfaces()
        RouDi->UserAppA: publish(ServiceRegistryTopic)
    end
end
deactivate RouDi
UserAppA->UserAppA: wake up from Listener::wait()
deactivate UserAppA

@enduml