PHP Australia Conference 2015

get_parent_class

(PHP 4, PHP 5)

get_parent_classGibt den Namen der Elternklasse eines Objektes zurück

Beschreibung

string get_parent_class ([ mixed $object ] )

Gibt den Namen der Elternklasse eines Objekts oder einer Klasse zurück.

Parameter-Liste

object

Das untersuchte Objekt oder der untersuchte Klassenname.

Rückgabewerte

Gibt den Namen der Elternklasse der Klasse zurück, von der object eine Instanz oder der Name ist.

Hinweis:

Falls das Objekt keine Elternklasse hat oder die angegebene Klasse nicht existiert, wird FALSE zurückgegeben.

Falls die Funktion außerhalb eines Objekts ohne Parameter aufgerufen wird, gibt sie FALSE zurück.

Changelog

Version Beschreibung
5.1.0 Falls die Funktion außerhalb eines Objekts ohne Parameter aufgerufen wurde, gab sie NULL und eine Warnung zurück. Jetzt gibt sie FALSE zurück.
5.0.0 Der Parameter object ist optional, falls die Funktion von einer Methode eines Objekts aufgerufen wird.
4.0.5 Falls object eine Zeichenkette ist, gibt diese Funktion den Namen der Elternklasse der Klasse mit diesem Namen zurück.

Beispiele

Beispiel #1 Die Verwendung von get_parent_class()

<?php

class vater {
  function 
vater()
  {
  
// implementiert etwas Logik
  
}
}

class 
kind extends vater {
  function 
kind()
  {
    echo 
"Ich bin das Kind von " get_parent_class($this) , "\n";
  }
}

class 
kind2 extends vater {
  function 
kind2()
  {
    echo 
"Ich bin ebenfalls das Kind von " get_parent_class('kind2') , "\n";
  }
}

$foo = new kind();
$bar = new kind2();

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Ich bin das Kind von vater
Ich bin ebenfalls das Kind von vater

Siehe auch

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User Contributed Notes 10 notes

up
1
levu
3 years ago
I wrote a simple function doing the reverse thing: get the children:

<?php
function get_child($instance, $classname) {
   
$class = $classname;
   
$t = get_class($instance);
    while ((
$p = get_parent_class($t)) !== false) {
        if (
$p == $class) {
            return
$t;
        }
       
$t = $p;
    }
    return
false;
}

abstract class
A {
    function
someFunction() {
        return
get_child($this, __CLASS__);
    }
}

class
B extends A {

}

class
C extends B {

}

$c = new C();
echo
$c->someFunction(); //displays B

?>
up
0
falundir at gmail dot com
2 years ago
You can use this function to find common parent of multiple objects or classes.

<?php
/**
* Returns name of the first (in class hierarchy) common parent class of all provided objects or classes.
* Returns FALSE when common class is not found.
*
* @param mixed $objects Array that can contain objects or class names.
* @return mixed
*/
function get_first_common_parent($objects) {
   
$common_ancestors = null;
    foreach(
$objects as $object) {
        if (
is_object($object)) {
           
$class_name = get_class($object);
        } else {
           
$class_name = $object;
        }
       
       
$parent_class_names = array();
       
$parent_class_name = $class_name;
        do {
           
$parent_class_names[] = $parent_class_name;
        } while(
$parent_class_name = get_parent_class($parent_class_name));
       
        if (
$common_ancestors === null) {
           
$common_ancestors = $parent_class_names;
        } else {
           
$common_ancestors = array_intersect($common_ancestors, $parent_class_names);
        }
    }
   
    return
reset($common_ancestors);
}
?>

Example:

<?php
class A {
}

    class
B extends A {
    }
   
        class
D extends B {
        }
       
        class
E extends B {
        }

    class
C extends A {
    }

        class
F extends C {
        }
   
            class
G extends F {
            }

class
H {
}

//returns "A"
get_first_common_parent(array('G', 'E'));

//returns "F"
get_first_common_parent(array(new G(), 'F'));

//returns false (no common parent)
get_first_common_parent(array('C', 'H'));

//returns false (non-existent class provided)
get_first_common_parent(array(new B(), 'X'));
?>
up
0
michael at getsprink dot -- com
5 years ago
This little snippet to get the inheritance tree might be useful to someone.

<?php

header
("Content-Type: text/plain;");

class
Top {
  public function
getParents($class=null, $plist=array()) {
   
$class = $class ? $class : $this;
   
$parent = get_parent_class($class);
    if(
$parent) {
     
$plist[] = $parent;
     
/*Do not use $this. Use 'self' here instead, or you
       * will get an infinite loop. */
     
$plist = self::getParents($parent, $plist);
    }
    return
$plist;
  }
}

class
Middle extends Top {
 
}

class
Bottom extends Middle {
 
}

$o = new Bottom();
print_r($o->getParents());

?>
up
0
ssb45 at cornell dot edu
6 years ago
"'If called without parameter outside object' What on earth does that mean?"

There are two places this could be called:
1. From within a member function of an object.  In this case, it may be called with no parameters and will return the parent class of the object owning the member function.  (If the parameter is included, then it will return the parent class of the specified class as normal.)

2. From outside an object (i.e., global or function scope).  In this case, PHP doesn't know what class you're talking about if you don't include a parameter, so it returns FALSE.  (But, of course, it works if you specify the class with the parameter.)
up
0
marcus at synchromedia dot co dot uk
6 years ago
"If called without parameter outside object" What on earth does that mean?

What I can tell you, and that is not documented, is that if the object in question does not have an explicitly declared parent class, it does return boolean false. It doesn't for example return 'stdClass' on the basis that all objects are derived from that.
up
0
birkholz at web dot de
8 years ago
tim at correctclick dot com wrote:
<quote>
A slightly more cryptic but faster get_ancestors function:

<?php
function get_ancestors ($class) {
         
     for (
$classes[] = $class; $class = get_parent_class ($class); $classes[] = $class);
     return
$classes;
     
}
?>
(The second part of the for is implicitly testing for $class != "").  Recursion is considerably slower than looping, so you probably want to use this function.

Hope someone finds it useful.
</quote>

I would prefer this version, because it will create no duplicates:
<?php
function get_ancestors ($class) {
   
$classes = array($class);
    while(
$class = get_parent_class($class)) { $classes[] = $class; }
    return
$classes;
}

Greets, Dennis
?>
up
0
matt-php at DONT-SPAM-ME dot bitdifferent dot com
9 years ago
PHP (4 at least, dunno about 5) stores classnames in lower case, so:

<?PHP

class Foo
{
}

class
Bar extends Foo
{
}

echo
get_parent_class('Bar');

echo
"\n";

echo
get_parent_class('bar');

?>

will output:

foo
foo
up
0
radu dot rendec at ines dot ro
10 years ago
If the argument obj is a string and the class is not defined, then the function returns FALSE.

If the argument obj is an object created from a class with no ancestors (or a string representing a class with no ancestors), then the function returns FALSE.
up
0
tim at correctclick dot com
11 years ago
A slightly more cryptic but faster get_ancestors function:

function get_ancestors ($class) {
           
      for ($classes[] = $class; $class = get_parent_class ($class); $classes[] = $class);
      return $classes;
       
}

(The second part of the for is implicitly testing for $class != "").  Recursion is considerably slower than looping, so you probably want to use this function.

Hope someone finds it useful.
up
-1
eric dot brison at anakeen dot com
12 years ago
To return all ancestors class of an object

function get_ancestors_class($classname) {
  $father = get_parent_class($classname);

  if ($father != "") {

    $ancestors = get_ancestors_class($father);
    $ancestors[] = $father;
  }
  return $ancestors;
}

example :
-----------
Class C  {

}

Class B extends C {

}

Class A extends B {

}
print_r (get_ancestors_class("a"));
print_r (get_ancestors_class("b"));

example result :
---------------
Array
(
    [0] => c
    [1] => b
)
Array
(
    [0] => c
)
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