set and get methods for user-defined hgsetget classes

Dear all,

I would appreciate some feedback regarding the appropriate use of "set" and "get" methods within user-defined classes that inherit from the hgsetget class. My problem has nothing to do with graphics, all I'm trying to do is to program in an OO fashion.

Here's an example. Lets assume there is the user-defined class

classdef myclass < hgsetget
    properties (Access = 'protected')
        myproperty
    end

When I tried to invoke a get method in a different class with something like

value = get(obj,'myproperty');

I got the following error message

"Getting the 'myproperty' property of the 'myclass' class is not allowed."

By inheriting hgsetget I believe I don't have to define the set and get methods if I simply want their primary functionality, but this may be the first point I'm wrong. Please let me know if I must include in the public methods' definition something like

function value = get.myproperty(obj)
    value = obj.myproperty;
end

function obj = set.myproperty(obj,value)
    obj.myproperty= value;
end

or the problem is elsewhere. Thanks.

PS: in a previous version of my code, I had all my classes inherit a user-defined master class, but this turned out not to be a good thing to do.

Answer 1

[Walter Roberson]

Isn't this just because you declared the property to be protected? A protected property should not be accessible outside the methods (or the methods of a subclass.)

[Georgios]

Well, the idea is to implement as good data hiding as possible. I believe the properties should be protected, and the class should have public member set and get functions to manipulate the property values outside the class. At least this works in languages such as C++.