Is there a way to disable adding properties into a class from an instance of the class?

Question

Is there a way to disable adding properties into a class from an instance of the class.

What I mean is this:

Consider this class:

class a {
 pri         


        

Answer 1

Perhaps you can implement __set() and throw an exception from there:

class a {
    private $v1;
    public $v2;

    public function __set($name, $value) {
        throw new Exception("Cannot add new property \$$name to instance of " . __CLASS__);
    }
}