Matlab責任鏈模式

責任鏈模式（Chain of Responsibility Pattern）為請求創建了一個接收者對象的鏈。這種模式給予請求的類型，對請求的發送者和接收者進行解耦，本人根據https://www.runoob.com/design-pattern/chain-of-responsibility-pattern.html所給的例子，用Matlab代碼實現責任鏈模式

AbstractLogger.m

classdef AbstractLogger < handle & matlab.mixin.Heterogeneous
    properties(Constant)
        INFO = 1;
        DEBUG = 2;
        ERROR = 3;
    end
    properties(Access = protected)
        level
        nextLogger = AbstractLogger.empty();
    end
    methods(Abstract,Access = protected)
        write(~);
    end
    methods
        function setNextLogger(obj,nextLogger)
            obj.nextLogger = nextLogger;
        end
        
        function logMessage(obj,level,message)
            if(obj.level <= level)
                obj.write(message);
            end
            if ~isempty(obj.nextLogger)
                obj.nextLogger.logMessage(level, message);
            end
        end
    end
end

　ConsoleLogger.m

classdef ConsoleLogger < AbstractLogger
    methods
        function obj=ConsoleLogger(level)
            obj.level = level;
        end
    end
    methods(Access = protected)
        function write(~,message)
            disp("Standard Console::Logger: " + message);
        end
    end
end

　FileLogger.m

classdef FileLogger < AbstractLogger
    methods
        function obj=FileLogger(level)
            obj.level = level;
        end
    end
    methods(Access = protected)
        function write(~,message)
            disp("File Console::Logger: " + message);
        end
    end   
end

　ErrorLogger.m

classdef ErrorLogger < AbstractLogger
    methods
        function obj=ErrorLogger(level)
            obj.level = level;
        end
    end
    methods(Access = protected)
        function write(~,message)
            disp("Error Console::Logger: " + message);
        end
    end
end

　測試代碼：

errorLogger = ErrorLogger(AbstractLogger.ERROR);
fileLogger = FileLogger(AbstractLogger.DEBUG);
consoleLogger = ConsoleLogger(AbstractLogger.INFO);

errorLogger.setNextLogger(fileLogger);
fileLogger.setNextLogger(consoleLogger);
 
loggerChain = errorLogger;
loggerChain.logMessage(AbstractLogger.INFO, "This is an information.");
loggerChain.logMessage(AbstractLogger.DEBUG, "This is a debug level information.");
loggerChain.logMessage(AbstractLogger.ERROR, "This is an error information.");