python版本的命令模式

# -*- coding:UTF-8 -*-

import abc


class Command(metaclass=abc.ABCMeta):

    def __init__(self, receiver):
        self._receiver = receiver

    @abc.abstractmethod
    def execute(self):
        pass


class ConcreteCommand(Command):
    def execute(self):
        self._receiver.action()


class Invoker:
    def __init__(self):
        self.__command = None

    def set_command(self, command):
        self.__command = command

    def execute_command(self):
        self.__command.execute()


class Receiver:
    def action(self):
        print("执行请求")


if __name__=="__main__":
    r = Receiver()
    c = ConcreteCommand(r)
    i = Invoker()
    i.set_command(c)
    i.execute_command()