MATLAB: Class Property: Array of Objects

arrayclassdependentMATLABobjectoopproperties

I would like to create a "Dependent Property" inside a "Main Class" that will handle a array of objects of "Sub Class".
Exemple:
classdef main_class
   properties
      number
   end
   properties (Dependent)
       % prop will be a array of sub_class object
       % the size of this array will depend/change on the "number" property
       prop = sub_class();
   end
end
If I set:
main = main_class();
main.number = 3;
I would like to get:
main.prop = [sub_class(1) sub_class(2) sub_class(3)]
To me is important that "prop" be a dependent property to automatic change the number of the elements in the array.
How could I do that? Thanks!

Best Answer

I'm with Adam, I don't think you want a dependent property. dependent does not mean that the property value is recalculated when some other property change, it means that property value is created every time you ask for it. That value is not stored in the class.
In your case, you would be better off creating a setter method for your number property that automatically update the array size of the normal prop property:
classdef main_class
   properties
      number
      prop
   end
   methods
      function this = main_class(number)   %constructor
         if nargin == 0
            this.number = 0;
         else
            this.number = number;
         end
         this = this.create_subarray;
      end
      function this = set.number(this, value)  %set method for number. reset prop at the same time
         this.number = value;
         this = this.create_subarray;
      end
      function this = create_subarray(this)
         this.prop = sub_class.empty;
         for n = 1:this.number
            this.prop(n) = sub_class(n);
         end
      end
   end
end
As Adam and Andrew have commented, hopefully sub_class is not actually a subclass of main class.
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