#命令模式
class Command():
    def order(self):
        pass
class ACommand(Command):
    def __init__(self,receive):
        self.__receive=receive
    def order(self):
        print("A Command")
        self.__receive.doSomething()
class BCommand(Command):
    def __init__(self,receive):
        self.__receive=receive
    def order(self):
        print("B Command")
        self.__receive.doSomething()
class AReceive():
    def doSomething(self):
        print("A receive")
class BReceive():
    def doSomething(self):
        print("B receive")
class Invoker():
    def __init__(self,command):
        self.__command=command
    def action(self):
        self.__command.order()
t=Invoker(BCommand(AReceive()))
t.action()