中介者模式(Mediator Pattern)是用來降低多個對象和類之間的通信複雜性。這種模式提供了一箇中介類,該類通常處理不同類之間的通信,並支持鬆耦合,使代碼易於維護。想象一個亂糟糟的開發小組的工作狀態,組員之間雖然在一起協同工作,但是意見難以統一,總是相互指揮,導致工作進度滯後。這時候,就需要一個仲裁者。所有的組員將自己的情況彙報給仲裁者,仲裁者會從團隊的整體考慮,然後下達指令。仲裁者負責統一大家的意見。這樣,團隊的交流過程就變成了組員向仲裁者報告,仲裁者向組員下達指令的形式,而組員之間不再詢問和溝通,這就是Mediator模式。
本文根據https://blog.csdn.net/niunai112/article/details/79913833所給的實例,用Matlab語言實現中介者模式
Mediator.m (抽象的中介者類)
classdef Mediator < handle
properties
userlist = User.empty();
end
methods(Abstract)
sendToAll(~,~);
sendToPerson(~,~,~);
join(~,~);
leave(~,~);
end
end
ChatPlatform.m (具體的中介者類,ConcreteMediator)
classdef ChatPlatform < Mediator
methods
function sendToAll(obj,msg)
for i=1:length(obj.userlist)
obj.userlist(i).accept(msg);
end
end
function sendToPerson(obj,name,msg)
user = obj.userlist([obj.userlist.name] == name);
for i = 1:length(user)
user.accept(msg);
end
end
function join(obj,user)
obj.userlist(end + 1) = user;
end
function leave(obj,user)
obj.userlist = obj.userlist(obj.userlist ~= user);
end
end
end
User.m (抽象的同事類, Colleague)
classdef User < handle & matlab.mixin.Heterogeneous
properties
mediator
name
end
methods
function obj = User(name, mediator)
obj.name = name;
obj.mediator = mediator;
end
function sendToAll(obj,msg)
obj.mediator.sendToAll(msg);
end
function sendToPerson(obj,name,msg)
obj.mediator.sendToPerson(name,msg);
end
function join(obj)
obj.mediator.join(obj);
end
function leave(obj)
obj.mediator.leave(obj);
end
end
methods(Abstract)
accept(~,~);
end
end
NormalUser.m (具體的同事類, ConcreteColleague)
classdef NormalUser < User
methods
function obj = NormalUser(name, mediator)
obj = obj@User(name, mediator);
end
function accept(obj,msg)
disp("[" + datestr(now) + "]" + obj.name + " accepted msg: " + msg);
end
end
end
測試代碼:
chatPlatform = ChatPlatform();
a = NormalUser("A", chatPlatform);
b = NormalUser("B", chatPlatform);
c = NormalUser("C", chatPlatform);
a.join();
b.join();
c.join();
disp("-----------------A羣發送消息------------------");
a.sendToAll("A:大家聽得到嗎?");
disp("-----------------A給B私發消息------------------");
a.sendToPerson("B", "A:B,我只想和你說");
disp("-----------------B給A私發消息------------------");
b.sendToPerson("A","B:可以,請說" );
disp("-----------------A離開聊天室------------------");
a.leave();
disp("-----------------B羣發送消息------------------");
b.sendToAll("B:A能聽到嗎");
運行結果:
參考資料
https://www.runoob.com/design-pattern/mediator-pattern.html
https://blog.csdn.net/qq_39384184/article/details/80631275