require that an object passed into an objective C method conform to a protocol? -

Is this possible? For example, I have a square triangle datative with an init method. Currently the method has been declared as follows:

  - (id) initWithFrame: (CGRact) frame Rep: ( Id) delegateObject;  

I want delegateObject to be consistent with the UITextFieldDelegate protocol. But what is the syntax for this?

  - (id) initWithFrame: (CGRect) frame rep: (id & lt; UITextFieldDelegate & gt;) delegateObject;