class_implements

(PHP 5, PHP 7)

class_implements — 返回指定的类实现的所有接口。

说明

class_implements ( mixed $class [, bool $autoload ] ) : array

本函数返回一个数组，该数组中包含了指定类class及其父类所实现的所有接口的名称。

参数

class

对象（类实例）或字符串（类名称）。

autoload

是否允许使用__autoload 魔术函数来自动装载该类。默认值为TRUE。

返回值

调用成功则返回一个数组，否则返回FALSE。

更新日志

版本 说明
5.1.0 增加了允许参数class为字符串的选项。增加了autoload参数。

范例

Example #1 class_implements() example

<?php

interface foo { }
class bar implements foo {}

print_r(class_implements(new bar));

// since PHP 5.1.0 you may also specify the parameter as a string
print_r(class_implements('bar'));


function __autoload($class_name) {
   require_once $class_name . '.php';
}

// use __autoload to load the 'not_loaded' class
print_r(class_implements('not_loaded', true));

?>

以上例程的输出类似于：

Array
(
    [foo] => foo
)

Array
(
    [interface_of_not_loaded] => interface_of_not_loaded
)

参见

User Contributed Notes

sam at rmcreative dot ru 03-Apr-2019 07:16
The order of interfaces is not reliable and varies between PHP versions.
a dot panek at brainsware dot org 05-Nov-2013 01:29
Calling class_implements with a non-loadable class name or a non-object results in a warning:

<?php
// Warning: class_implements(): Class abc does not exist and could not be loaded in /home/a.panek/Projects/sauce/lib/Sauce/functions.php on line 196

$interfaces = class_implements('abc');
?>

This is not documented and should just return FALSE as the documentation above says.
paul at paulferrett dot com 30-Dec-2009 05:35
You can also check if a class implements an interface using instanceof.

E.g.
<?php
if($myObj instanceof MyInterface) {
    echo "It is! It is!";
}
?>
trollll23 at yahoo dot com 25-Oct-2005 12:57
Luckily, it prints out superinterfaces as well in reverse order so iterative searching works fine:

    <?php
   
    interface InterfaceA { }
   
    interface InterfaceB extends InterfaceA { }
   
    class MyClass implements InterfaceB { }
   
    print_r(class_implements(new MyClass()));
   
    ?>

prints out:

    Array
    (
        [InterfaceB] => InterfaceB
        [InterfaceA] => InterfaceA
    )
ludvig dot ericson at gmail dot nospam dot com 01-Aug-2005 12:41
Hint:
<?php
in_array("your-interface", class_implements($object_or_class_name));
?>
would check if 'your-interface' is ONE of the implemented interfaces.
Note that you can use something similar to be sure the class only implements that, (whyever you would want that?)
<?php
array("your-interface") == class_implements($object_or_class_name);
?>

I use the first technique to check if a module has the correct interface implemented, or else it throws an exception.