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

    説明

    get_parent_class(object|string $object_or_class = ?): string|false

    オブジェクトあるいはクラスの親クラスの名前を取得します。

    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。

    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。

    変更履歴

    バージョン 説明
    8.3.0 get_parent_class() を引数なしでコールすると、 E_DEPRECATED が発生するようになりました。 これより前のバージョンでは、クラスの内部でこの関数をコールすると、 そのクラスの名前を返していました。
    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

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    User Contributed Notes 7 notes

    up
    7
    yukal dot alexander at gmail dot com
    6 years ago
    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
    up
    1
    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.
    up
    1
    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'));
    ?>
    up
    1
    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

    ?>
    up
    0
    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.)
    up
    0
    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
    up
    -1
    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.
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