class Test {
public function __construct() {
self::runTest();
Test::runTest();
}
public static function runTest() {
echo "Test running";
}
}
// echoes 2x "Test running"
new Test();
Is there any difference between self::runTest() and Test::runTest()? And if so, which one should I use?
self::runTest() when calling the method within the class and Test::runTest() when outside the class?
you should call self::runTest() from inside the class methods and Test::runTest() outside of the class methods
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?
exactly!
self::runTest() when calling the method within the class and Test::runTest() when outside the class?- yes