get_parent_class

(PHP 4, PHP 5, PHP 7)

get_parent_class返回对象或类的父类名

说明

string get_parent_class ([ mixed $obj ] )

如果 obj 是对象,则返回对象实例 obj 所属类的父类名。

如果 obj 是字符串,则返回以此字符串为名的类的父类名。此功能是在 PHP 4.0.5 中增加的。

Note:

自 PHP 5 起,如果在对象的方法内调用,则 obj 为可选项。

Example #1 使用 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();

?>

以上例程会输出:

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

参见 get_class()is_subclass_of()

参数

object

The tested object or class name

返回值

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.

更新日志

版本 说明
Before 5.1.0 If called without parameter outside object, this function would have returned NULL with a warning.
Since 5.0.0 The object parameter is optional if called from the object's method.
Since 4.0.5 If object is a string, returns the name of the parent class of the class with that name.

范例

Example #2 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();

?>

以上例程会输出:

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

参见

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User Contributed Notes 5 notes

up
3
falundir at gmail dot com
5 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
2
matt-php at DONT-SPAM-ME dot bitdifferent dot com
13 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
levu
6 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
radu dot rendec at ines dot ro
13 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
-1
ssb45 at cornell dot edu
9 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.)
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