Beispiele
Overloading is defining a method multiple times with different input parameters, then conditionally running whichever method matches the provided input.
It looks like the "overload" function just enables magic methods for a class, which can be used in implementing an extremely janky simulation of overloading.
Also, it seems that magic methods are enabled by default in php5 regardless of whether the overload function has been run on a class.
Einige einfache Beispiele für die Verwendung der overload()-Funktion:
Beispiel #1 Eine PHP-Klasse überladen
<?php
class OO {
var $a = 111;
var $elem = array('b' => 9, 'c' => 42);
// Callback-Methode für die Abfrage einer Eigenschaft
function __get($prop_name, &$prop_value)
{
if (isset($this->elem[$prop_name])) {
$prop_value = $this->elem[$prop_name];
return true;
} else {
return false;
}
}
// Callback-Methode für das Setzen einer Eigenschaft
function __set($prop_name, $prop_value)
{
$this->elem[$prop_name] = $prop_value;
return true;
}
}
// Hier überladen wir das OO-Objekt
overload('OO');
$o = new OO;
echo "\$o->a: $o->a\n"; // print: $o->a: 111
echo "\$o->b: $o->b\n"; // print: $o->b: 9
echo "\$o->c: $o->c\n"; // print: $o->c: 42
echo "\$o->d: $o->d\n"; // print: $o->d:
// füge einen neuen Eintrag zum $elem-Array in OO hinzu
$o->x = 56;
// instanziiere stdclass (ist in PHP 4 eingebaut)
// $val ist nicht überladen!
$val = new stdclass;
$val->prop = 555;
// setze "a" als Array mit dem $val-Objekt als Value
// __set() wird dies aber trotzdem dem $elem-Array zuordnen
$o->a = array($val);
var_dump($o->a[0]->prop);
?>
add a note
User Contributed NotesEine PHP-Klasse überladen
scurvysquid at yahoo dot com
04-Jun-2009 02:43
04-Jun-2009 02:43
Anonymous
26-Mar-2009 07:48
26-Mar-2009 07:48
You can't redeclare because PHP won't know which one to use. Use a default value and test conditionally instead such as
<?php
public function method($arg=false){
if($arg==false){
//do something
} else {
//do something else
}
}
?>
ly dot sitthykun at yahoo dot com
22-Jan-2009 05:47
22-Jan-2009 05:47
<?php
class Foo{
public function method(){
echo "call Method no paramater";
}
public function method($par){
echo "call Method has a paramater";
}
}
$foo = new Foo();
echo $foo->method("param");]
?>
#output:
Fatal error: Cannot redeclare Foo::method() in class_overload.php on line 6
why?
we can not create the same method name.