命令模式

命令模式

 

模式说明

将请求封装成对象，从而使可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤消的操作。

模式结构图

程序示例

说明：调用者是遥控器，接受者是电视

代码：

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()

运行结果：

参考来源：

http://www.cnblogs.com/chenssy/p/3679190.html

http://www.cnblogs.com/wuyuegb2312/archive/2013/04/09/3008320.html

http://www.cnblogs.com/Terrylee/archive/2006/07/17/334911.html