TrafficLight

red : Lamp

yellow : Lamp

green : Lamp

leftGreenArrow : Lamp ?

[ LeftGreenArrow ]

[ leftArrow ]

rightGreenArrow : Lamp ?

[ RightGreenArrow ]

arrowsOff ?

[ arrowsOff <=> no leftGreenArrow.on && no leftGreenArrow.flashing ]

[ arrowsOff <=> no rightGreenArrow.on && no rightGreenArrow.flashing ]

emergencyVehicle ?

xor TrafficSignals

[ emergencyVehicle && allWayYellow => allYellow ]

[ emergencyVehicle && no allWayYellow => warning ]

proceed

[ no emergencyVehicle ]

[ red.off ]

[ yellow.off ]

[ green.on ]

[ leftGreenArrow => leftGreenArrow.on ]

[ rightGreenArrow => rightGreenArrow.on ]

prepareToStop

[ no emergencyVehicle ]

[ red.off ]

[ yellow.on ]

[ green.off ]

[ arrowsOff ]

stop

[ no emergencyVehicle ]

[ red.on ]

[ yellow.off ]

[ green.off ]

[ arrowsOff ]

warning

[ red.off ]

[ yellow.flashing ]

[ green.off ]

[ arrowsOff ]

prepareToGo

[ no emergencyVehicle ]

[ redAndYellowToGreen ]

[ red.on ]

[ yellow.on ]

[ green.off ]

[ arrowsOff ]

allStop

[ no emergencyVehicle ]

[ allWayFlashingRedAsStop ]

[ red.flashing ]

[ yellow.off ]

[ green.off ]

[ arrowsOff ]

allYellow

[ allWayYellow ]

[ red.off ]

[ yellow.flashing ]

[ green.off ]

[ arrowsOff ]

advancedLeft

[ no emergencyVehicle ]

[ advancedOrExtendedLeft ]

[ red.on ]

[ yellow.off ]

[ greenFlashing => green.flashing ]

[ leftArrow => leftGreenArrow.flashing && green.off ]

extendedLeft

[ no emergencyVehicle ]

[ advancedOrExtendedLeft ]

[ red.on ]

[ yellow.off ]

[ greenFlashing => green.flashing ]

[ leftArrow => leftGreenArrow.flashing && green.off ]

abstract xor Lamp

on

off

flashing

TrafficLightSystem

Lamps

LeftGreenArrow ?

RightGreenArrow ?

redAndYellowToGreen ?

allWayFlashingRedAsStop ?

allWayYellow ?

xor advancedOrExtendedLeft ?

greenFlashing

leftArrow

[ no LeftGreenArrow ]

[ no RightGreenArrow ]

[ no redAndYellowToGreen ]

[ no allWayFlashingRedAsStop ]

[ no allWayYellow ]

[ no advancedOrExtendedLeft ]

[ emergencyVehicle ]