Matlab享元模式(Flyweight)

享元模式(Flyweight)通過共享技術實現相同或相似對象的重用，可以減少創建對象的數量，以減少內存佔用和提高性能。Java String的常量池，python logging，線程池，數據庫連接池都用到了享元模式。享元模式與單例模式類似，都具有共享變量的特徵。本文通過使用matlab語言對享元模式進行實現。

IFlyweight.m

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

 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
    end
end

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
    end
end

test.m 

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

運行結果：

參考資料：

https://segmentfault.com/a/1190000015035255?utm_source=index-hottest

https://blog.csdn.net/justloveyou_/article/details/55045638