Python: Facade Pattern

DuFacade.py

import os
import re
import threading

# 外观模式 Facade Pattern


class _IgnitionSystem(object):

    @staticmethod
    def produce_spark():
        return True


class _Engine(object):

    def __init__(self):
        self.revs_per_minute = 0

    def turnon(self):
        self.revs_per_minute = 2000

    def turnoff(self):
        self.revs_per_minute = 0


class _FuelTank(object):

    def __init__(self, level=30):
        self._level = level

    @property
    def level(self):
        return self._level

    @level.setter
    def level(self, level):


       self._level = level


class _DashBoardLight(object):

    def __init__(self, is_on=False):
        self._is_on = is_on

    def __str__(self):
        return self.__class__.__name__

    @property
    def is_on(self):
        return self._is_on

    @is_on.setter
    def is_on(self, status):
        self._is_on = status

    def status_check(self):
        if self._is_on:
            print("{}: 开启".format(str(self)))
        else:
            print("{}: 关闭".format(str(self)))


class _HandBrakeLight(_DashBoardLight):
    pass


class _FogLampLight(_DashBoardLight):
    pass


class _Dashboard(object):

    def __init__(self):
        self.lights = {"手刹": _HandBrakeLight(), "雾": _FogLampLight()}

    def show(self):
        for light in self.lights.values(): light.status_check()


# Facade 列要对齐，否则方法（函数）调用不出来  Geovin Du,geovindu,涂聚文注，格式很关键
class Car(object):

    def __init__(self):
        self.ignition_system = _IgnitionSystem()
        self.engine = _Engine()
        self.fuel_tank = _FuelTank()
        self.dashboard = _Dashboard()

    @property
    def km_per_litre(self):
        return 17.0

    def consume_fuel(self, km):
        litres = min(self.fuel_tank.level, km / self.km_per_litre)
        self.fuel_tank.level -= litres

    def start(self):
        print("\n开始启动...")
        self.dashboard.show()
        if self.ignition_system.produce_spark():
            self.engine.turnon()
        else:
            print("不能开始。点火系统故障")

    def has_enough_fuel(self, km, km_per_litre):
        litres_needed = km / km_per_litre
        if self.fuel_tank.level > litres_needed:
            return True
        else:
            return False

    def drive(self, km=100):
            print("\n")
            if self.engine.revs_per_minute > 0:
                while self.has_enough_fuel(km, self.km_per_litre):
                    self.consume_fuel(km)
                    print("geovindu开车 {}km".format(km))
                    print("剩余的燃料 {:.2f}l ".format(self.fuel_tank.level))
            else:
                print("不能开车。引擎已关闭!")

    def park(self):
                print("\n停车...")
                self.dashboard.lights["手刹"].is_on = True
                self.dashboard.show()
                self.engine.turnoff()

    def switch_fog_lights(self, status):
                print("\n切换 {} 雾灯...".format(status))
                boolean = True if status == "ON" else False
                self.dashboard.lights["雾"].is_on = boolean
                self.dashboard.show()

    def fill_up_tank(self):
                print("\n油箱已满!")
                self.fuel_tank.level = 100



# the main function is the Client
def main():
   car = Car()
   car.start()
   car.drive()
   car.switch_fog_lights("ON")
   car.switch_fog_lights("OFF")
   car.park()
   car.fill_up_tank()
   car.drive()
   car.start()
   car.drive()

　　

调用：

main.py 

# 外观模式 Facade  Pattern
# DuFacade.main()

car = DuFacade.Car()
car.start()
car.drive()
car.switch_fog_lights("ON")
car.switch_fog_lights("OFF")
car.park()
car.fill_up_tank()
car.drive()
car.start()
car.drive()

　　

输出：

开始启动...
_HandBrakeLight: 关闭
_FogLampLight: 关闭


开车 100km
剩余的燃料 24.12l 
开车 100km
剩余的燃料 18.24l 
开车 100km
剩余的燃料 12.35l 
开车 100km
剩余的燃料 6.47l 
开车 100km
剩余的燃料 0.59l 

切换 ON 雾灯...
_HandBrakeLight: 关闭
_FogLampLight: 开启

切换 OFF 雾灯...
_HandBrakeLight: 关闭
_FogLampLight: 关闭

停车...
_HandBrakeLight: 开启
_FogLampLight: 关闭

油箱已满!


不能开车。引擎已关闭!

开始启动...
_HandBrakeLight: 开启
_FogLampLight: 关闭


开车 100km
剩余的燃料 94.12l 
开车 100km
剩余的燃料 88.24l 
开车 100km
剩余的燃料 82.35l 
开车 100km
剩余的燃料 76.47l 
开车 100km
剩余的燃料 70.59l 
开车 100km
剩余的燃料 64.71l 
开车 100km
剩余的燃料 58.82l 
开车 100km
剩余的燃料 52.94l 
开车 100km
剩余的燃料 47.06l 
开车 100km
剩余的燃料 41.18l 
开车 100km
剩余的燃料 35.29l 
开车 100km
剩余的燃料 29.41l 
开车 100km
剩余的燃料 23.53l 
开车 100km
剩余的燃料 17.65l 
开车 100km
剩余的燃料 11.76l 
开车 100km
剩余的燃料 5.88l 
开车 100km
剩余的燃料 0.00l 

Process finished with exit code 0