The order of interfaces is not reliable and varies between PHP versions.
(PHP 5, PHP 7)
class_implements — 返回指定的类实现的所有接口。
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。
调用成功则返回一个数组，否则返回FALSE。
| 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。
|
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
)
The order of interfaces is not reliable and varies between PHP versions.
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
$interfaces = class_implements('abc');
?>
This is not documented and should just return FALSE as the documentation above says.
You can also check if a class implements an interface using instanceof.
E.g.
<?php
if($myObj instanceof MyInterface) {
echo "It is! It is!";
}
?>
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
)
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.