An output of the entire inheritance chain using closures, recursion, and OOP
class ParentClass {
public static function getChain() {
$chain = null;
return $function = function($className='') use (& $chain, & $function) {
if (empty($className))
$className = static::class;
if (empty($chain))
$chain = $className;
$parent = get_parent_class($className);
if ($parent !== false) {
$chain .= " > {$parent}";
return $function($parent);
}
return $chain;
};
}
}
class Child extends ParentClass {}
class SubChild extends Child {}
class Sub2 extends SubChild {}
class Sub3 extends Sub2 {}
class Sub4 extends Sub3 {}
class Sub5 extends Sub4 {}
class Sub6 extends Sub5 {}
class Sub7 extends Sub6 {}
printf("%s\n", Sub7::getChain()());
$getChain = Sub7::getChain();
printf("%s\n", $getChain('Sub3'));
Output is:
Sub7 > Sub6 > Sub5 > Sub4 > Sub3 > Sub2 > SubChild > Child > ParentClass
Sub3 > Sub2 > SubChild > Child > ParentClass
get_parent_class
(PHP 4, PHP 5, PHP 7, PHP 8)
get_parent_class — オブジェクトの親クラスの名前を取得する
パラメータ
-
object_or_class -
調べたいオブジェクトあるいはクラスの名前。 オブジェクトのメソッドからコールされた場合、このパラメータはオプションとなります。
戻り値
object_or_class
がインスタンスあるいは名前であるクラスの親クラス名を返します。
注意:
オブジェクトが親を持たない場合や、 指定したクラスが存在しない場合は
falseを返します。
オブジェクトの外部からこのパラメータを省略してコールすると、
この関数は false を返します
変更履歴
| バージョン | 説明 |
|---|---|
| 8.0.0 |
object_or_class は、
オブジェクトまたは有効なクラス名を受け入れるようになりました。
|
例
例1 get_parent_class() の使用例
<?php
class Dad {
function __construct()
{
// ロジックを実装する
}
}
class Child extends Dad {
function __construct()
{
echo "I'm " , get_parent_class($this) , "'s son\n";
}
}
class Child2 extends Dad {
function __construct()
{
echo "I'm " , get_parent_class('child2') , "'s son too\n";
}
}
$foo = new child();
$bar = new child2();
?>上の例の出力は以下となります。
I'm Dad's son I'm Dad's son too
参考
- get_class() - オブジェクトのクラス名を返す
- is_subclass_of() - あるオブジェクトが指定したクラスのサブクラスに属するか (あるいは指定したインターフェイスを実装しているか) どうかを調べる
- class_parents() - 与えられたクラスの親クラスを返す
add a note
User Contributed Notes 7 notes
yukal dot alexander at gmail dot com ¶
5 years ago
matt-php at DONT-SPAM-ME dot bitdifferent dot com ¶
20 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
falundir at gmail dot com ¶
12 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'));
?>
levu ¶
13 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
?>
jake at qzdesign dot co dot uk ¶
5 years ago
Note that from PHP 5.5 you can also use `parent::class` from within a method, e.g.
<?php
function child()
{
echo "I'm ", parent::class, "'s son\n";
}
?>
Looks a bit tidier and technically probably more optimal, as it avoids a function call lookup.
ssb45 at cornell dot edu ¶
16 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.)
radu dot rendec at ines dot ro ¶
20 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.
