get_parent_class

(PHP 4, PHP 5, PHP 7)

get_parent_class — Retrieves the parent class name for object or class

Description

string get_parent_class ([ mixed $object ] )

Retrieves the parent class name for object or class.

Parameters

object: The tested object or class name. This parameter is optional if called from the object's method.

Return Values

Returns the name of the parent class of the class of which object is an instance or the name.

Note:
If the object does not have a parent or the class given does not exist FALSE will be returned.

If called without parameter outside object, this function returns FALSE.

Changelog

Version	Description
5.1.0	If called without parameter outside object, this function would have returned `NULL` with a warning, but now returns `FALSE`.

Examples

Example #1 Using get_parent_class()


<?php

class dad {
    function dad()
    {
    // implements some logic
    }
}

class child extends dad {
    function child()
    {
        echo "I'm " , get_parent_class($this) , "'s son\n";
    }
}

class child2 extends dad {
    function child2()
    {
        echo "I'm " , get_parent_class('child2') , "'s son too\n";
    }
}

$foo = new child();
$bar = new child2();

?>

The above example will output:

I'm dad's son
I'm dad's son too

User Contributed Notes

levu

5 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

?>

tim at correctclick dot com

13 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.

michael at getsprink dot -- com

7 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());

?>

falundir at gmail dot com

4 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'));
?>

matt-php at DONT-SPAM-ME dot bitdifferent dot com

11 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

ssb45 at cornell dot edu

7 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.)

marcus at synchromedia dot co dot uk

8 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.

birkholz at web dot de

10 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
?>

radu dot rendec at ines dot ro

12 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.

eric dot brison at anakeen dot com

14 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
)