Question

here is a code:

abstract class A
{
    abstract public function add();

    public function callItself()
    {
        echo __CLASS__.':'.__FUNCTION__.' ('.__LINE__.')<br>';
        if (rand(1,100) == 5) { die; }
        $this->callItself();
    }
}

class B extends A
{
    public function add()
    {
        echo __CLASS__.':'.__FUNCTION__.' ('.__LINE__.')<br>';
    }
}

class C extends B
{
    public function add()
    {
        echo __CLASS__.':'.__FUNCTION__.' ('.__LINE__.')<br>';
        parent::add();
        parent::callItself();
    }

    public function callItself()
    {
        echo __CLASS__.':'.__FUNCTION__.' ('.__LINE__.')<br>';
        throw new Expection('You must not call this method');
    }
}

$a = new C();
$a->add();
die;

in class C the callItself() must not be called, so it drops an exception. I cant set it private as we know 🙂 but at 10 line, the $this->callItself(); calls that method of **C** instead of A so it dies. But I dont want it, how to dodge that?

Answer 1

Use self::callItself() instead of $this->callItself();

Replace

public function callItself()
{
    echo __CLASS__.':'.__FUNCTION__.' ('.__LINE__.')<br>';
    if (rand(1,100) == 5) { die; }
    $this->callItself();
}

With

public function callItself() {
    echo __CLASS__ . ':' . __FUNCTION__ . ' (' . __LINE__ . ')<br>';
    if (rand(0, 2) == 0) { <------- Better Probability 
        die();
    }
    self::callItself(); <---- This would continue to call A:callItself until die
}

Output

C:add (23)
B:add (17)
A:callItself (7)
A:callItself (7)
A:callItself (7)
A:callItself (7)
A:callItself (7)
A:callItself (7)