MATLAB: Callback within the class

callbackclassMATLABmyclassself created classes

hi, i got the following class:
 classdef form<handle
          properties
              type = 'square'
              b
              h
              A
              Iy
              Iz
              Wy
              Wz
          end %properties
          events
              calc
          end %events
          methods
              function f = form(b,h)
                  f.b=b;
                  f.h=h;
                  f.update()
              end 
              function obj = update(obj)
                  obj.A= obj.h*obj.b;
                  obj.Iy= obj.h^3*obj.b/12;
                  obj.Iz= obj.b^3*obj.h/12;
                  obj.Wy= obj.h^2*obj.b/6;
                  obj.Wz= obj.b^2*obj.h/6;
              end
          end % events
      end%class
how do i manage to call the function update everytime when either form.a or form.h of an instance is changed withoud adding a listener to the instance? is there a way to directly built thin in the class definition?
thanks a lot for help

Best Answer

It seems like all the properties other than b and h should be dependent. This would allow you to get rid of the update method. If you really want to go the update route, you could write a set method for b and h which will call the update method.
Does the following work for you?
classdef form<handle
  properties
    type = 'square'
    b
    h
  end
  properties (Dependent)
    A
    Iy
    Iz
    Wy
    Wz
  end %properties

  methods
    function f = form(b,h)
      f.b=b;
      f.h=h;
    end
    
    function val = get.A(obj)
      val= obj.h*obj.b;
    end
    
    function val = get.Iy(obj)
      val= obj.h^3*obj.b/12;
    end
    
    function val = get.Iz(obj)
      val= obj.b^3*obj.h/12;
    end
    
    function val = get.Wy(obj)
      val= obj.h^2*obj.b/6;
    end
    
    function val = get.Wz(obj)
      val = obj.b^2*obj.h/6;
    end
  end % events

end%class

You could also go with the "ugly" update method:
classdef form<handle
  properties
    type = 'square'
    b
    h
    A
    Iy
    Iz
    Wy
    Wz
  end %properties
  methods
    function f = form(b,h)
      f.b=b;
      f.h=h;
    end
    function set.b(obj, val)
      obj.b = val;
      obj.update;
    end
    function set.h(obj, val)
      obj.h = val;
      obj.update;
    end
    function obj = update(obj)
      obj.A= obj.h*obj.b;
      obj.Iy= obj.h^3*obj.b/12;
      obj.Iz= obj.b^3*obj.h/12;
      obj.Wy= obj.h^2*obj.b/6;
      obj.Wz= obj.b^2*obj.h/6;
    end
  end % events
end%class
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