Intercepting an object property call?

Question

PHP

Is it possible in php to intercept a property call?
Suppose the data object has a param property, by default it is empty, the first time you access param so that you can execute the def. method for filling it and in the future, if not empty, then do not call the filling method.

Answer 1

Accessing a property via a getter/setter.

class Foo {
    private $param;

    public function getParam() {
        //... тут своя логика
        return $this->param;
    }
}