Polymorphism Example

vehicles_part_2.py

__author__ = 'David Gotz, gotz@unc.edu, Onyen = gotz'

# Define the superclass Vehicle
class Vehicle:
    # Define the initialization method
    def __init__(self, driver):
        self.driver = driver
        self.passengers = None

    # Load a list of passengers into the vehicle
    def load(self, passengers):
        self.passengers = passengers

    # Unload the list of passengers.  Returns None if the vehicle is empty.
    def unload(self):
        passengers = self.passengers
        self.passengers = None
        return passengers

    # Move the vehicle
    def move(self):
        # All vehicles have a drive
        print(self.driver + ":\t", end="")
        # Each vehicle has its own sound!
        self.make_sound()
        # All vehicles have passengers
        print(self.passengers)

    # A default sound, for generic "Vehicles"
    def make_sound(self):
        for i in range(3):
            print("Moving..", end="")


# GroundVehicle: a subclass of Vehicle for ground transportation vehicles
class GroundVehicle(Vehicle):
    # The initialization method
    def __init__(self, driver):
        # Call the superclass init
        Vehicle.__init__(self, driver)

    # Override the make_sound method
    def make_sound(self):
        for i in range(3):
            print("Vroom...", end="")


# AirVehicle: a subclass of Vehicle for air transportation vehicles
class AirVehicle(Vehicle):
    # The initialization method
    def __init__(self, driver):
        # Call the superclass init
        Vehicle.__init__(self, driver)

    # Override the make_sound method
#    def make_sound(self):
#        for i in range(3):
#            print("Shhhh...", end="")


# A main function to coordinate the program
def main():
    # Vacation time! We will need to drive to the airport, fly to our destination airport, then drive to the hotel.
    # That means two taxis and a plane.
    rdu_taxi = GroundVehicle("Alice")
    big_airplane = AirVehicle("Jane")
    airport_tram = Vehicle("Susan")
    hawaii_taxi = GroundVehicle("Bob")

    # Now let's put them into a list so we can treat them all as just "vehicles".
    vacation_vehicles = [rdu_taxi, big_airplane, airport_tram, hawaii_taxi]

    # Time for the trip.  Let's go!
    passengers = ["Anne", "David", "Sarah", "Issac", "Adina"]
    for vehicle in vacation_vehicles:
        vehicle.load(passengers)
        vehicle.move()
        passengers = vehicle.unload()


# Start the program.
main()