命令模式

class TV(object):
    def open(self):
        print ‘turn on tv‘
    def close(self):
        print ‘turn off tv‘
    def changeChannel(self):
        print ‘change channel‘

class Command(object):
    _tv = TV()
    def __init__(self,tv):
        self._tv = tv
    def execute(self):
        pass

class TurnOnCommand(Command):
    def execute(self):
        self._tv.open()

class TurnOffCommand(Command):
    def execute(self):
        self._tv.close()

class ChangeChannelCommand(Command):
    def execute(self):
        self._tv.changeChannel()

class Controller(object):
    #_turnon = None
    #_turnoff = None
    #_changechannel = None
    def __init__(self,turnon,turnoff,changechannel):
        self._changechannel = changechannel
        self._turnon = turnon
        self._turnoff = turnoff

    def open(self):
        self._turnon.execute()
    def close(self):
        self._turnoff.execute()
    def changechannel(self):
        self._changechannel.execute()


if ‘__main__‘ == __name__:
    tv = TV()
    turnon = TurnOnCommand(tv)
    turnoff = TurnOffCommand(tv)
    changechannel = ChangeChannelCommand(tv)

    controller = Controller(turnon,turnoff,changechannel)
    controller.open()
    controller.changechannel()
    controller.close()