Test method existence on Objects

Question

I have a cell array of Matlab objects, something like:

objs = {Object1(), Object2(), Object3()};

These objects are all of different types. Some of them will have a method, let's call it myMethod(). I want to do something like:

for o = objs
  if hasMethod(o, 'myMethod()')
    o.myMethod();
  end
end

and my difficulty is that I don't know how to do hasMethod - exist doesn't seem helpful here.

I could use a try - catch, but I'd rather do something neater. Is there a way to do this? Should I just change my design instead?

Answer 1

Another option is to use the meta class.

  obmeta = metaclass(ob);
  methodNames = cellfun(@(x){x.Name},obmeta.Methods);

You can also get additional information from obmeta.Methods like

• Amount of input/output parameters.
• Access type
• In which class the method is defined.

Also, metaclass can be constructed from the name of the class, without an instance, which can be an advantage in some situations.

Answer 2

Ah, found it. Not very exciting - you can get a list of methods with the methods command. So to check if an object has a method,

if any(strcmp(methods(o), 'myMethod'))
  o.myMethod();
end