@startuml
alt control message without any parameters
Application -> "Event Manager" as evm : ScreenLightControlMessage
else contol message with parameters
Application -> "Event Manager" as evm : ScreenLightSetParameters
end
evm -> "ScreenLightControl" as slc: processRequest()
slc -> "Eink Frontlight" : request
slc -> "Light Sensor" : request
@enduml