call_user_method
Something to note,
If the $original class has not yet been defined or loaded, the auto loader will be invoked in order to try and load it.
If the class for which you are trying to create an alias does not exist, or can not be loaded with the auto loader, you will generate a PHP Warning.
class_alias
(PHP 5 >= 5.3.0)
class_alias — Creates an alias for a class
Description
bool 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.
Parameters
- original
-
The original class.
- alias
-
The alias name for the class.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #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);
?>
The above example will output:
bool(true) bool(false) bool(true) bool(true) bool(true) bool(true) bool(true)
See Also
- get_parent_class() - Retrieves the parent class name for object or class
- is_subclass_of() - Checks if the object has this class as one of its parents
add a note
User Contributed Notes
class_alias
adam at adamhahn dot com
06-Sep-2011 12:13
programmer-comfreek at hotmail dot com
15-Aug-2011 09:38
If you defined the class 'original' in a namespace, you will have to specify the namespace(s), too:
<?php
namespace ns1ns2ns3;
class A {}
class_alias('ns1\ns2\ns3\A', 'B');
/* or if you want B to exist in ns1\ns2\ns3 */
class_alias('ns1\ns2\ns3\A', 'ns1\ns2\ns3\B');
?>
nicolas dot grekas+php at gmail dot com
31-Dec-2010 01:09
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-Dec-2010 02:41
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
03-Sep-2009 03:43
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.