@startuml

class CardHolder{
    String Name
    Boolean Suspended
}
class Invoice {
    Int Number
    Double Discount
    String status
}
class InvoiceLine{
    Int Number
}
class GasStation{
    String Name
}
class Pump {
    String Type
    Boolean InUse
    Double RefillThreshold
    Boolean Blocked
}
class RefuelTurn {
    Int RefuelTurnNumber
}
class CashTurn {}


Pump "1" -- "0..*" RefuelTurn
Pump "1" -- "0..*" CashTurn
GasStation"1" -- "0..*" Pump 
CardHolder "1" -- "0..*" Invoice
CardHolder "1" -- "0..*" RefuelTurn
Invoice "1" -- "0..*" InvoiceLine
RefuelTurn"1" -- "0..1" InvoiceLine

@enduml