Matlab享元模式

享元模式(Flyweight)通过共享技术实现相同或相似对象的重用，可以减少创建对象的数量，以减少内存占用和提高性能。Java String的常量池，python logging，线程池，数据库连接池都用到了享元模式。享元模式与单例模式类似，都具有共享变量的特征。本文通过使用matlab语言对享元模式进行实现。

 IFlyweight.m

classdef IFlyweight < handle    methods(Abstract)        print(~);    endend

Flyweight.m

classdef Flyweight < IFlyweight    properties        color    end       methods        function obj = Flyweight(color)            obj.color =  color;        end        function print(obj)            disp("color:"+obj.color)        end    endend

FlyweightFactory.m

classdef FlyweightFactory < handle        methods(Static)        function res = getFlyweightMap()            persistent flyweightMap;            if isempty(flyweightMap) || ~isvalid(flyweightMap)                flyweightMap = containers.Map();            end            res = flyweightMap;        end        function obj = getFlyweight(color)            flyweightMap = FlyweightFactory.getFlyweightMap();            if(~flyweightMap.isKey(color))                flyweightMap(color) = Flyweight(color);            end            obj = flyweightMap(color);        end        function size = getFlyweightMapSize()            flyweightMap = FlyweightFactory.getFlyweightMap();            size = flyweightMap.length();        end    endend

测试代码

fw1 = FlyweightFactory.getFlyweight('Red');fw2 = FlyweightFactory.getFlyweight('Blue');fw3 = FlyweightFactory.getFlyweight('Red');fw1.print();fw2.print();fw3.print();disp(FlyweightFactory.getFlyweightMapSize());clear('FlyweightFactory');