@startuml

abstract class Node { /' (also ConcreteObserver) '/
	+ label: string
	+ type: string
	+ addOutput(Net*)
	+ addInput(Net*)
	- inputs: Net*[]
	- outputs: Net*[]
}
class Net { /' (also ConcreteSubject) '/
	- level: SignalLevel
	+ setLevel(SignalLevel)
	' only call notify when setLevel actually changes the level!!!!!!!
}

class Subject {
	- observers: Observer*[]
	+ attach(Observer*)
	+ detach(Observer*)
	+ notify()
}
interface Observer {
	+ update()
}

class GateAnd
class GateNand
class GateNor
class GateNot
class GateOr
class GateXor
class NodeOutput
class NodeInput

enum SignalLevel {
  LOW
	HIGH
	UNDEFINED
}

Node <|-[dashed]-- GateAnd
Node <|-[dashed]-- GateNand
Node <|-[dashed]-- GateNor
Node <|-[dashed]-- GateNot
Node <|-[dashed]-- GateOr
Node <|-[dashed]-- GateXor
Node <|-[dashed]-- NodeOutput
Node <|-[dashed]-- NodeInput

Subject <|-- Net
Observer <|-[dashed]- Node
Node -> "owner" Net
Observer "*" - Subject

class Parser {
	+ loadFromFile()
}

class CircuitFactory {
	+ run()
	+ configure()
}


@enduml