MATLAB: Is there a callback to check if any of the objects properties are changed using OOP in MATLAB 7.6 ( R2008a)

callbackchangechangescheckdetectMATLABoop

I am working with object oriented programming (OOP) in MATLAB 7.6 (R2008a).

I am looking for a function which is called a if any of the objects properties are changed using the dot operator. How can this be done in MATLAB?

Best Answer

There is no easy way to do this. However you can use the SUBSASGN function which is used for subscripted assignment for objects. An example is given below:

classdef foo < handle
      properties(SetObservable = true)
          val = 1;
      end
      methods
          function obj = subsasgn(obj, s, val)
              disp('hello');
              val = builtin('subsasgn', obj, s, val);
          end
      end
end

Now, at the MATLAB Command prompt, if you type:

f = foo;
f(1)

would give you the output:

 ans = 
 foo handle
 properties:
     val: 1
 lists of methods, events, superclasses

or typing

f.val

would give you the following output:

 ans =
      1

Related Solutions

MATLAB: Is the wrong SUBSASGN function being called when I have an overloaded SUBSASGN function present

In a call to an overloaded function, the actual function being called is decided by MATLAB based on the class of the objects in the entire argument list. MATLAB determines which argument has the highest object precedence and the class of

this object controls the method selection. Hence, in this case:

obj.(s(1).subs) = subsasgn(obj.(s(1).subs), s(2:end), val);
 the variable 'val' is the dominant object and hence controls the function call. For a detailed explanation of this process and to manipulate the Object Precedence, please refer to the MATLAB documentation on Object Precedence.

You can manipulate the Object Precedence using the INFERIORTO and SUPERIORTO functions. Also, you can enforce the built-in SUBASGN function to be called by using:

obj.(s(1).subs) = builtin('subsasgn', obj.(s(1).subs), s(2:end), val);

MATLAB: Setter method does not work on inherited class

You're using handle syntax to set the property of your class, yet your class is a value class. Either change your setFoo to:

function obj = setFoo(obj, foo)
   obj.foo = foo;
end

and call it with:

test = test.setFoo(10);

or derive from handle:

classdef Foo < matlab.mixin.Heterogeneous & handle

Also, you can create setter and getter for the class properties, using this syntax

function set.foo(obj, value) %for handle class
   obj.foo = value;
end
function obj = set.foo(obj, value) % for value class
   obj.foo = value;
end

which you call simply with:

obj.foo = 10; %for value and handle class.

Best Answer

Related Solutions

MATLAB: Is the wrong SUBSASGN function being called when I have an overloaded SUBSASGN function present

MATLAB: Setter method does not work on inherited class

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