You can also check if a class implements an interface using instanceof.
E.g.
<?php
if($myObj instanceof MyInterface) {
echo "It is! It is!";
}
?>
(PHP 5 >= 5.1.0, PHP 7)
class_implements — Return the interfaces which are implemented by the given class or interface
This function returns an array with the names of the interfaces that the
given class and its parents implement.
classAn object (class instance) or a string (class or interface name).
autoloadWhether to allow this function to load the class automatically through the __autoload() magic method.
An array on success, or FALSE on error.
| Version | Description |
|---|---|
| 5.1.0 |
Added the option to pass the class parameter as
a string. Added the autoload parameter.
|
Example #1 class_implements() example
<?php
interface foo { }
class bar implements foo {}
print_r(class_implements(new bar));
// since PHP 5.1.0 you may also specify the parameter as a string
print_r(class_implements('bar'));
function __autoload($class_name) {
require_once $class_name . '.php';
}
// use __autoload to load the 'not_loaded' class
print_r(class_implements('not_loaded', true));
?>
The above example will output something similar to:
Array
(
[foo] => foo
)
Array
(
[interface_of_not_loaded] => interface_of_not_loaded
)
You can also check if a class implements an interface using instanceof.
E.g.
<?php
if($myObj instanceof MyInterface) {
echo "It is! It is!";
}
?>
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.
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.
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
)