#!/usr/bin/python
# coding:utf8
"""
命令行模式
"""
import abc
class Receiver(object):
'''
命令接收者，正在执行命令的地方，实现了众多命令函数
'''
def start(self):
print('execute start command')
def stop(self):
print('execute stop command')
def suspend(self):
print('execute suspend command')
def play(self):
print('execute play command')
class Command(object):
"""
command抽象方法，子类必须要实现execute方法
"""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def execute(self):
pass
class Start_command(Command):
"""
start命令类，对命令接收者类中start方法的封装
"""
def __init__(self, receiver):
self.receiver = receiver
def execute(self):
self.receiver.start()
class Stop_command(Command):
"""
stop命令类，对命令接收者类中stop方法的封装
"""
def __init__(self, receiver):
self.receiver = receiver
def execute(self):
self.receiver.stop()
class Client(object):
"""
调用命令的客户端
"""
def __init__(self, command):
self.command = command
def command_do(self):
self.command.execute()
if __name__ == '__main__':
receiver = Receiver()
start_command = Start_command(receiver)
client = Client(start_command)
client.command_do()
# 可以直接更换命令，如下，把start命令，换成stop命令
stop_command = Stop_command(receiver)
client.command = stop_command
client.command_do()
命令模式实现了分离，有助于控制命令
