Here's a bit of example code to show what's happening:
class A {
function __construct(){
echo get_class($this),"\n";
echo self::tellclass();
echo A::tellclass();
}
static function tellclass(){
echo __METHOD__,' ', __CLASS__,"\n";
}
}
class B extends A {
}
class C extends A{
function __construct(){
echo "parent constructor:\n";
parent::__construct();
echo "self constructor:\n";
echo get_class($this),"\n";
echo self::tellclass();
echo C::tellclass();
}
static function tellclass(){
echo __METHOD__, ' ', __CLASS__,"\n";
}
}
$a= new A;
// A
//A::tellclass A
//A::tellclass A
$b= new B;
//B
//A::tellclass A
//A::tellclass A
$c= new C;
//parent constructor:
//C
//A::tellclass A
//A::tellclass A
//self constructor:
//C
//C::tellclass C
//C::tellclass C
The take-away point is that A::tellclass()
always calls the tellclass
method defined in A
. But self::tellclass()
allows child classes to use their own version of tellclass()
if they have one. As @One Trick Pony notes, you should also check out late static binding: https://www.php.net/manual/en/language.oop5.late-static-bindings.php
self::runTest() when calling the method within the class and Test::runTest() when outside the class?
- yes