MATLAB: Checking dataType instead typecast at property or argument validation

Question

Hello, I would like to use property/ argument validation in a different way. I would like to prevent the assignment of other types as the specified meta.Validation.Class.

As an example:

I've the following class

classdef TestPropertyValidation
   properties
      myProperty double {mustBeNumeric}
   end
   methods
       function obj = TestPropertyValidation(stringVal)
           obj.myProperty = stringVal;
       end
   end
end

If I pass now …

>> TestPropertyValidation("Hello")
ans = 
  TestPropertyValidation with properties:
    myProperty: NaN

I guess because of the conversion:

>> double("Hello")
ans =
   NaN
>> isnumeric(NaN)
ans =
  logical
   1

But I like the way specifying conditions for properties. And I would like to use it in a bigger project. There we have to make sure no uncontrolled conversions happen between object constructor calls with lots of paramters passed to constructors and methods. I would like to prevent that for example 1+'1' := 50 operations can happen because of a misplaced method parameter for example.

I know I can use the ValidatorFunctions to prevent that for example a character is passed instead a double but only if I don't state the desired class, for example 'double' to don't have a conversion. It would be very nice having the type check and afterwards the validatorFunctions for further conditions to values. Is there a way to change the validation of properties and arguments to have a validation of the class instead of a conversion at validation order step 1.

Thank you.

Answer 1

There's no way to do this with validators in R2019b and the datatype coercion will always happen. You can use a set.property setter method to type check new values.