设计模式之享元模式

from abc import ABCMeta, abstractmethod


# 运用共享技术有效地支持大量细粒度对象的复用，类似于对象池模式，不过对象池是为了节省对象不断创建销毁的时间，
# 享元模式是为了防止重复创建相似或相同的对象，导致内存泄漏
# 两个主要角色：享元对象、享元工厂
class Flyweight(metaclass=ABCMeta):
    """享元类"""
    @abstractmethod
    def operation(self, extrinsicState):
        pass


class FlyweightImpl(Flyweight):
    """享元模式的具体实现类"""
    def __init__(self, color):
        self.__color = color

    def operation(self, extrinsicState):
        print("%s取得%s色颜料" %(extrinsicState, self.__color))


class FlyweightFactory:
    """享元工厂"""
    def __init__(self):
        self.__flyweights = {}

    def getFlyweight(self, key):
        pigment = self.__flyweights.get(key, FlyweightImpl(key))
        return pigment


def testFlywieght():
    factory = FlyweightFactory()
    pigmentRed = factory.getFlyweight("红")
    pigmentRed.operation("梦之队")
    pigmentBlue = factory.getFlyweight("蓝")
    pigmentBlue.operation("梦之队")
    pigmentBlue1 = factory.getFlyweight("蓝")
    pigmentBlue1.operation("和平队")


testFlywieght()