python设计模式之桥接模式

来源：互联网发布：功率串联和并联的算法编辑：程序博客网时间：2024/05/22 08:01

桥接模式

这个模式其实就是把产品类的实现和抽象类分离，能够灵活的变化，假如你记得状态模式,它是修改内部属性，而桥接模式是指定好内部属性，每个产品类指定这个属性被桥接模式类调用，适用于产品类可能经常调整变化，这样还能减少了产品类之间的耦合

python的例子

这里实现一个打印操作系统名字的功能

class Bridge(object):    def __init__(self):        self.__implementation = None    def someFunctionality(self):        raise NotImplemented()class UseCase1(Bridge):    # 根据初始化参数传入实现的产品类    def __init__(self, implementation):        self.__implementation = implementation    # 根据传入的产品类的属性打印结果    def someFunctionality(self):        print "UseCase1: ",        self.__implementation.anotherFunctionality()class UseCase2(Bridge):    def __init__(self, implementation):        self.__implementation = implementation    def someFunctionality(self):        print "UseCase2: ",        self.__implementation.anotherFunctionality()class ImplementationInterface:    def anotherFunctionality(self):        raise NotImplemented# 这里其实才是实现的产品类class Linux(ImplementationInterface):    # 它定义了这个方法，回应操作系统的名字    def anotherFunctionality(self):        print "Linux!"class Windows(ImplementationInterface):    def anotherFunctionality(self):        print "Windows."def main():    linux = Linux()    windows = Windows()    useCase = UseCase1(linux)    useCase.someFunctionality()    useCase = UseCase1(windows)    useCase.someFunctionality()    useCase = UseCase2(linux)    useCase.someFunctionality()    useCase = UseCase2(windows)    useCase.someFunctionality()if __name__ == "__main__":    main()

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