MATLAB: Is constructor method the only method that creates an object in a class definition

class object-orientedoop

Another way to ask this question is: how do I create a value class object as the output of a handle class ordinary method? For example,

classdef handleClassA < handle
    properties
    end
    methods
        function obj = handleClassA(varargin)
            ...
        end
        function ValueClassobj2 = unknownmethod(handleClassAobj, ValueClassobj1)
            ValueClassobj2.property1 = ...
            some_sort_function(handleClassAobj.property3, ValueClassobj1.property1);
            ...
        end
    end
end

If I do it the above way, the output is a struct with field property1, etc., not a object of a class.

Best Answer

I think you are trying to do,

    function ValueClassobj2 = unknownmethod(handleClassAobj, ValueClassobj1)
         ValueClassobj2 = ValueClassobj1; %clone of obj1
      ValueClassobj2.property1 = ...
     some_sort_function(handleClassAobj.property3, ValueClassobj1.property1);
    ...
    end

Related Solutions

MATLAB: Passing on superclass property values to subclass

I think what Adam said here is the key:

but it knows it is creating this as part of creating the subclass

In other words, the 'obj' output of the myclass() constructor is not an ordinary output variable. Not only is it pre-initialized when the myclass workspace is entered, but the pre-initialization type also depends on how myclass() was invoked. If it was invoked using a subclass object, as in subclassObj@myclass() then obj is pre-intialized to the subclass type. This is confirmed by the following,

     classdef myclass 
         methods 
             function obj=myclass
                 disp ' '
                      disp(['obj is a ' class(obj) ' object'])
                 disp ' '
             end
         end
     end
    classdef mysubclass < myclass
        methods 
             function obj=mysubclass
                    obj=obj@myclass;
             end
         end
    end

which gives the behavior:

    >> myclass;
    obj is a myclass object
    >> mysubclass;
    obj is a mysubclass object

And therefore, assigning obj a superclass object, even in the superclass constructor, can force it to be the wrong type.

MATLAB: Super class get callers name

Found it. Just call this:

 me = class(obj);

this gives the name of the created subclass. I call it in the constructor of the superclass:

 function obj = mySuperClass() %constructor
   me = class(obj);
   obj.name = me;
 end

Best Answer

Related Solutions

MATLAB: Passing on superclass property values to subclass

MATLAB: Super class get callers name

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