Python适配器模式,代码,思考等

# -*- coding: utf-8 -*-
# author:baoshan
class Computer:
  def __init__(self, name):
    self.name = name
  def __str__(self):
    return 'the {} computer'.format(self.name)
  def execute(self):
    return 'executes a program'
class Synthesizer:
  def __init__(self, name):
    self.name = name
  def __str__(self):
    return 'the {} synthesizer'.format(self.name)
  def play(self):
    return 'is playing an electronic song'
class Human:
  def __init__(self, name):
    self.name = name
  def __str__(self):
    return '{} the human'.format(self.name)
  def speak(self):
    return 'says hello'
class Adapter:
  def __init__(self, obj, adapted_methods):
    self.obj = obj
    self.__dict__.update(adapted_methods)
def __str__(self):
    return str(self.obj)
def main():
  objects = [Computer('Asus')]
  synth = Synthesizer('moog')
  objects.append(Adapter(synth, dict(execute=synth.play)))
  human = Human('Bob')
  objects.append(Adapter(human, dict(execute=human.speak)))
  for i in objects:
    print('{} {}'.format(str(i), i.execute()))
if __name__ == '__main__':
  main()

代码输出:

the Asus computer executes a program
the moog synthesizer is playing an electronic song
Bob the human says hello

------------------------------------------------------------------------------------------

我们设法使得Human和Synthesizer类与客户端所期望的接口兼容,且无需改变它们的源代码。这太棒了!

这里有一个为你准备的挑战性练习,当前的实现有一个问题,当所有类都有一个属性name时,以下代码会运行失败。

  for i in objects:
    print('{}'.format(i.name))

首先想想这段代码为什么会失败"htmlcode">

class Adapter:
  def __init__(self, obj, adapted_methods):
    self.obj = obj
    self.__dict__.update(adapted_methods)
    self.name = obj.name
  def __str__(self):
    return str(self.obj)

然后在main函数中获取对应的name,如下

def main():
  objects = [Computer('Asus')]
  synth = Synthesizer('moog')
  objects.append(Adapter(synth, dict(execute=synth.play)))
  human = Human('Bob')
  objects.append(Adapter(human, dict(execute=human.speak)))
  for i in objects:
    print('{} {}'.format(str(i), i.execute()))
    print('{}'.format(i.name))
if __name__ == '__main__':
  main()

输出结果如下:

the Asus computer executes a program
Asus
the moog synthesizer is playing an electronic song
moog
Bob the human says hello
Bob

参考自:《精通Python设计模式》

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。

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