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Klassen- und Objekt-Funktionen

<<call_user_method

class_exists>>

class_alias

(PHP 5 >= 5.3.0)

class_aliasCreates an alias for a class

Beschreibung

boolean class_alias ([ string $original [, string $alias ]] )

Creates an alias named alias based on the defined class original. The aliased class is exactly the same as the original class.

Parameter-Liste

original

The original class.

alias

The alias name for the class.

Rückgabewerte

Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.

Beispiele

Beispiel #1 class_alias() example

<?php

class foo { }

class_alias('foo''bar');

$a = new foo;
$b = new bar;

// the objects are the same
var_dump($a == $b$a === $b);
var_dump($a instanceof $b);

// the classes are the same
var_dump($a instanceof foo);
var_dump($a instanceof bar);

var_dump($b instanceof foo);
var_dump($b instanceof bar);

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

bool(true)
bool(false)
bool(true)
bool(true)
bool(true)
bool(true)
bool(true)

Siehe auch


3 BenutzerBeiträge:
- Beiträge aktualisieren...
nicolas dot grekas+php at gmail dot com
31.12.2010 10:09
At first, you might wonder that:
<?php class A {}; class_alias('A', 'B'); ?>

is equivalent to:
<?php class A {}; class B extends A {}; ?>

BUT when derivation creates a new class name - that means, you can then instantiate a new kind of objects - aliasing is just what it says: a synonym, so objects instantiated with the aliased name are of the exact same kind of objects instantiated with the non-aliased name.

See this code for example:
<?php
class A {};
class
B1 extends A {};
class_alias('A', 'B2');

$b1 = new B1; echo get_class($b1); // prints B1
$b2 = new B2; echo get_class($b2); // prints A !
?>
nicolas dot grekas+php at gmail dot com
30.12.2010 23:41
class_alias also works for interfaces!

<?php
interface foo {}
class_alias('foo', 'bar');
echo
interface_exists('bar') ? 'yes!' : 'no'; // prints yes!
?>
paul [dot] kotets [at] gmail [dot] com
3.09.2009 12:43
This function will appear in PHP 5.3 (at least I can use it with PHP 5.3, build Aug 7 2009 08:21:14)
For older versions of PHP I wrote the next function:

<?php
if (!function_exists('class_alias')) {
    function
class_alias($original, $alias) {
        eval(
'abstract class ' . $alias . ' extends ' . $original . ' {}');
    }
}
?>

Keyword 'abstract' is used for classes, which defines abstract methods.
This function is used in autoload purposes (when I extend classes), so abstract keyword doesn't broke anything for me.



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