大话设计模式（Python版）--享元模式

最新推荐文章于 2023-03-16 23:30:57 发布

jenny_yu1025

最新推荐文章于 2023-03-16 23:30:57 发布

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分类专栏： python 设计模式文章标签：设计模式

本文链接：https://blog.youkuaiyun.com/Jenny_yu1025/article/details/52994908

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本文探讨了享元模式在网站分类中的应用，通过具体Python代码实现，展示了如何利用该模式减少内存消耗并高效管理不同类型的网站实例。此外，还介绍了如何通过内部状态和外部状态来区分不同的网站使用场景。

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网站类：

#!/usr/bin/env python

class WebSite:
    def __init__(self, name):
        self.__name = name
    def Use(self):
        print('classify website:',self.__name)

def main():
    ps = WebSite('Product Show')
    ps.Use()
    ps2 = WebSite('Product Show')
    ps2.Use()
    ps3 = WebSite('Product Show')
    ps3.Use()
    ps4 = WebSite('blog Show')
    ps4.Use()
    
if __name__ == '__main__':
    main()

享元模式v1：

#!/usr/bin/env python
from abc import ABCMeta,abstractmethod

class Flyweight:
    __metaclass__ = ABCMeta
    @abstractmethod
    def Operation(self, extrinsicstate):
        pass
    
class ConcreteFlyweight(Flyweight):
    def Operation(self, extrinsicstate):
        print('concrete Flyweight:',extrinsicstate)

class UnShareConcreteFlyweight(Flyweight):
    def Operation(self, extrinsicstate):
        print('unshared concrete Flyweight:',extrinsicstate)

class FlyweightFactory:
    def __init__(self):
        self.__flyweights = dict()
        self.__flyweights['X'] = ConcreteFlyweight()
        self.__flyweights['Y'] = ConcreteFlyweight()        
        self.__flyweights['Z'] = ConcreteFlyweight()
    def GetFlyweight(self, key):
        return self.__flyweights[key]

def main():
    extrinsicstate = 22
    ff = FlyweightFactory()
    fwx = ff.GetFlyweight('X')
    fwx.Operation(extrinsicstate)
    fwy = ff.GetFlyweight('Y')
    fwy.Operation(extrinsicstate)
    fwz = ff.GetFlyweight('Z')
    fwz.Operation(extrinsicstate)
    usfw = UnShareConcreteFlyweight()
    usfw.Operation(extrinsicstate)
    
if __name__ == '__main__':
    main()

网站共享代码：

#!/usr/bin/env python
from abc import ABCMeta, abstractmethod
class WebSite:
    __metaclass__ = ABCMeta
    def Use(self):
        pass

class ConcreteWebSite(WebSite):
    def __init__(self, name):
        self.__name = name
    def Use(self):
        print('website classify:',self.__name)

class WebSiteFactory:
    def __init__(self):
        self.__flyweights = dict()
    def GetWebSiteCategory(self, key):
        if(key not in self.__flyweights):
            self.__flyweights[key] = ConcreteWebSite(key)
        return self.__flyweights[key]
    def GetWebSiteCount(self):
        return len(self.__flyweights)

def main():
    wsf = WebSiteFactory()
    fx = wsf.GetWebSiteCategory('X')
    fx.Use()
    fy = wsf.GetWebSiteCategory('Y')
    fy.Use()    
    fps = wsf.GetWebSiteCategory('product show')
    fps.Use()
    fb = wsf.GetWebSiteCategory('blog')
    fb.Use()
    print('the total number of website is',wsf.GetWebSiteCount())
            
if __name__ == '__main__':
    main()

内部状态与外部状态

#!/usr/bin/env python
from abc import ABCMeta, abstractmethod
class User:
    def __init__(self,name):
        self.__name = name
    @property
    def Name(self):
        return self.__name

class WebSite:
    __metaclass__ = ABCMeta
    @abstractmethod
    def Use(self, use):
        pass

class ConcreteWebSite(WebSite):
    def __init__(self, name):
        self.__name = name
    def Use(self, user):
        print("website classify :",self.__name,"user: ",user.Name)

class WebSiteFactory:
    def __init__(self):
        self.__flyweights = dict()
    def GetWebSiteCategory(self, key):
        if(key not in self.__flyweights):
            self.__flyweights[key] = ConcreteWebSite(key)
        return self.__flyweights[key]
    def GetWebSiteCount(self):
        return len(self.__flyweights)

def main():
    wsf = WebSiteFactory()
    fx = wsf.GetWebSiteCategory('X')
    fx.Use(User('freshman'))
    fy = wsf.GetWebSiteCategory('Y')
    fy.Use(User('BigBird'))    
    fps = wsf.GetWebSiteCategory('product show')
    fps.Use(User('Lily'))
    fb = wsf.GetWebSiteCategory('blog')
    fb.Use(User('Lucy'))
    print('the total number of website is',wsf.GetWebSiteCount())
            
if __name__ == '__main__':
    main()