certain-design-patterns/builder.py at master · laserattack/certain-design-patterns · GitHub

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from abc import ABC, abstractmethod

class Car:
    def __init__(self):
        self.seats = None
        self.engine = None
        self.trip_computer = None
        self.gps = None

    def __str__(self):
        return (f"Car with {self.seats} seats, {self.engine} engine, "
                f"trip computer: {self.trip_computer}, GPS: {self.gps}")

class CarManual:
    def __init__(self):
        self.seats = None
        self.engine = None
        self.trip_computer = None
        self.gps = None
    def __str__(self):
        return (f"Car manual:\nSeats: {self.seats}\nEngine: {self.engine}\n"
                f"trip computer: {self.trip_computer}\nGPS: {self.gps}")

class Builder(ABC):
    @abstractmethod
    def reset(self):
        pass
    @abstractmethod
    def set_seats(self, number):
        pass
    @abstractmethod
    def set_engine(self, engine_type):
        pass
    @abstractmethod
    def set_trip_computer(self, has_trip_computer):
        pass
    @abstractmethod
    def set_gps(self, has_gps):
        pass
    @abstractmethod
    def get_result(self):
        pass

class CarBuilder(Builder):
    def __init__(self):
        self.reset()
    def reset(self):
        self._car = Car()
        return self
    def set_seats(self, number):
        self._car.seats = number
        return self
    def set_engine(self, engine_type):
        self._car.engine = engine_type
        return self
    def set_trip_computer(self, has_trip_computer):
        self._car.trip_computer = has_trip_computer
        return self
    def set_gps(self, has_gps):
        self._car.gps = has_gps
        return self
    def get_result(self):
        car = self._car
        self.reset()
        return car

class CarManualBuilder(Builder):
    def __init__(self):
        self.reset()
    def reset(self):
        self._manual = CarManual()
        return self
    def set_seats(self, number):
        self._manual.seats = f"{number} seats"
        return self
    def set_engine(self, engine_type):
        self._manual.engine = f"engine type: {engine_type}"
        return self
    def set_trip_computer(self, has_trip_computer):
        self._manual.trip_computer = "Equipped with a trip computer" if has_trip_computer else "No trip computer"
        return self
    def set_gps(self, has_gps):
        self._manual.gps = "includes GPS navigation" if has_gps else "No GPS navigation"
        return self
    def get_result(self):
        manual = self._manual
        self.reset()
        return manual

class Director:
    def __init__(self, builder: Builder):
        self._builder = builder
    def set_builder(self, builder: Builder):
        self._builder = builder
    def construct_sport_car(self):
        self._builder.reset()
        self._builder.set_seats(2)
        self._builder.set_engine("V8")
        self._builder.set_trip_computer(True)
        self._builder.set_gps(True)
    def construct_suv(self):
        self._builder.reset()
        self._builder.set_seats(7)
        self._builder.set_engine("V6")
        self._builder.set_trip_computer(True)
        self._builder.set_gps(False)

director = Director(CarBuilder())
director.construct_sport_car()
print(director._builder.get_result())

director.set_builder(CarManualBuilder())
director.construct_sport_car()
print(director._builder.get_result())

director.set_builder(CarBuilder())
director.construct_suv()
print(director._builder.get_result())

director.set_builder(CarManualBuilder())
director.construct_suv()
print(director._builder.get_result())