OOP: $this or parent?

[lilleman]

Hi,

Which is the most correct way to access the methods of a parent class?
Should one use $this->method() or parent::method()?

Yours, Erik.

[reminder]

i use zends double collon for accessing parent classes
cheers

[Daimaju]

take a look at this:

class father
{
    var $foo = 'me';
    function getFoo(){
        return $this->foo;
    }
}
class child extends father
{
    function getme(){
        return parent::getFoo();
    }
    function getFoo(){
        return 'this is my Foo';
    }
}
$child = new child();
echo '->'.$child->getFoo().'<br />';
echo '::'.$child->getme(); 

the output is:

->this is my Foo
::me

So when using :: you always call the parent function, even if the child overwrites the parents function.

I always use $this->parentfunction(), but not for this reason, as i discovered it just now
I thought :: is for static calls, so i thought parent::getFoo() shouldn't return anything, but this would only bee if i'd use father::getFoo()

Do i make sense? nope, at least not to me

Edit:


I think parent::function makes only sense when used in the same function in the child class, e.g.

class child{

  function foo(){
     $ret = parent::foo();
     /*
     *do some calculations with $ret, 
     *that are not done in the parent class
     */
    return $ret;
 }
} 

[Tony Marston]

Use $this->method() if you want the version in the subclass to be executed. If it has not been defined in the subclass it will cascade up to the superclass.

User parent::method() if you want to execute the version in the superclass and ignore the version in the subclass completely. A common example is parent::__construct() when you want to execute the parent's constructor as well as the child's constructor as PHP does not do this by default.

[lilleman]

Hi,

Thanks guys.

Yours, Erik.