Constructor Not Assigning Values in Matlab - matlab

Question

I am trying to create a few objects in Matlab. I am used to programming in Java, but being able to do this in Matlab would be beneficial for my research.
So, I have a particular class:
classdef Lifter < handle
properties
weightClass = 0;
mean = 0;
var = 0;
nation = '';
end
methods
function Lifter = Lifter(weightClass,mean,var,nation) %Constructor
Lifter.weightClass = weightClass;
Lifter.mean = mean;
Lifter.var = var;
Lifter.nation = nation;
end
function set.weightClass(this,weightClass)
end
function set.mean(this,mean)
end
function set.var(this,var)
end
function set.nation(this,nation)
end
function value = get.weightClass(this)
value = this.weightClass;
end
function value = get.mean(this)
value = this.mean;
end
function var = get.var(this)
var = this.mean;
end
function nation = get.nation(this)
nation = this.nation;
end
end
end
Pretty standard, doesn't really do much.
So, in another page, I have:
function Competition()
Lifter1 = Lifter(56,1,1,'USA')
end
However, running this gives:
Lifter1 =
Lifter with properties:
weightClass: 0
mean: 0
var: 0
nation: ''
Any help to figure out why this values are not being initialized correctly from the constructor would be very helpful.
Also, an example of how to actually call a setter or getter method on my Lifter1 object would be helpful. Thank you!

Answer 1

Those setters are for dependent properties (declared as properties(Dependent)). But also, your setters are not implemented (empty), which means that all your property assignments won't do anything. Which means that the properties stay with the default values declared in the properties section.
Later Edit
If I would have to implement the class, I'd do it like in the following code:
classdef Lifter < handle
% --- PUBLIC SECTION ---
properties(Dependent)
weight_class;
end;
methods
function obj = Lifter(weight_class)
obj.weight_class = weight_class;
end;
function set.weight_class(obj, weight_class)
if ~isa(obj, 'Lifter') ...
|| ~isscalar(obj) ...
|| ~isvalid(obj)
error('Lifter:Arg', '"obj" must be a scalar valid handle object of class "Lifter".');
elseif ~isnumeric(weight_class) ...
|| ~isscalar(weight_class) ...
|| ~isreal(weight_class) ...
|| (weight_class <= 0) % + other value tests
error('Lifter:Arg', '"weight_class" must be a numeric positive scalar.');
else
obj.weight_class_ = double(weight_class);
end;
end;
function val = get.weight_class(obj)
val = obj.weight_class_;
end;
end;
% --- PRIVATE SECTION ---
properties(Access=private)
weight_class_;
end;
end
The code for the rest of the properties is similar. Test with:
a = Lifter(100); % Constructor + setter call
a.weight_class = 75; % Setter call
disp(a.weight_class); % Getter call
a.weight_class = '85'; % Setter call with wrong value

Answer 2

Your setters and getters should not contain dots (although I agree it would be more elegant your way if it worked):
function set.weightClass(this,weightClass)
end
Could be (should be) :
function set_weightClass(this,weightClass)
end
If I replace all of them, it works properly.