How do I write a common set method for multiple properties

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Kristina Kossarev 2021-3-30

0
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https://ww2.mathworks.cn/matlabcentral/answers/787619-how-do-i-write-a-common-set-method-for-multiple-properties

评论： per isakson 2021-4-1

I work within a project which has several classes which define properties that use essentially the same set method. To make the code more readable, I want to implement a commonsetter method. The overall goal is to include this commonsetter method in the superclass, so that all the classes could use it. Here is a minimum example:

classdef MyClass
	
	properties
		A
		B
	end
	
	methods
		
		function mc = MyClass(a,b) % Constructor
			mc.A = a;
			mc.B = b;
		end
		
		function mc = set.A(mc, value) % setter for A
			mc = mc.commonSetter(value, 'A');
		end
		
		function mc = set.B(mc, value) % setter for B
			mc = mc.commonSetter(value, 'B');
		end
		
		
	end
	
	methods(Access = protected)
		
		function mc = commonSetter(mc, value, property)
			% do some stuff
			disp('Made it into the commonSetter!')
			mc.(property) = value;
		end
		
	end
	
end
% tested with MyClass(1,2)

Unfortunatelly, I get following error: Maximum recursion limit of 500 reached.

My questions would be: Is there a way to use the commonsetter function for variables A and B? And what do I have to change if I want to include this commonsetter method in the superclass?

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Kristina Kossarev 2021-4-1

在 MATLAB Online 中打开

Thanks for the answer! Can you specify how you wouldoverwrite it? I tried to overwrite subsasgn based on the MatWorks documentation but I still get the same recursion error:

	methods(Access = protected)
		
		function mc = commonSetter(mc, value, property)
			% do some stuff
			disp('Made it into the commonSetter!')
% 			mc.(property) = value;
            S = struct('type', '.', 'subs', property);
            mc = subsasgn(mc, S, value);
        end
		
        function obj = subsasgn(obj,s,varargin)
            % Allow subscripted assignment to uninitialized variable
            if isequal(obj,[])
                obj = MyClass.empty;
            end
            switch s(1).type
                case '.'
                    if length(s) == 1
                        prop = s(1).subs;      % Property name
                        n = numel(obj);        % Number of elements in array
                        for k = 1:n
                            obj(k).(prop) = varargin{k};
                        end
                    else
                    % Call built-in for any other case
                    obj = builtin('subsasgn',obj,s,varargin{:});
                    end
                otherwise
                    error('Not a valid indexing expression')
            end
        end
    end