You can also check if a class implements an interface using instanceof.
E.g.
<?php
if($myObj instanceof MyInterface) {
echo "It is! It is!";
}
?>
class_implements
(PHP 5, PHP 7, PHP 8)
class_implements — Return the interfaces which are implemented by the given class or interface
Description
class_implements(object|string
$object_or_class, bool $autoload = true): array|false
This function returns an array with the names of the interfaces that the
given object_or_class and its parents implement.
Parameters
-
object_or_class -
An object (class instance) or a string (class or interface name).
-
autoload -
Whether to autoload if not already loaded.
Return Values
An array on success, or false when the given class doesn't exist.
Examples
Example #1 class_implements() example
<?php
interface foo { }
class bar implements foo {}
print_r(class_implements(new bar));
// you may also specify the parameter as a string
print_r(class_implements('bar'));
spl_autoload_register();
// use autoloading to load the 'not_loaded' class
print_r(class_implements('not_loaded', true));
?>The above example will output something similar to:
Array
(
[foo] => foo
)
Array
(
[foo] => foo
)
Array
(
[interface_of_not_loaded] => interface_of_not_loaded
)
Notes
Note: To check that an object implements an interface,
instanceofor the is_a() function should be used instead.
See Also
- class_parents() - Return the parent classes of the given class
- get_declared_interfaces() - Returns an array of all declared interfaces
- is_a() - Checks whether the object is of a given type or subtype
instanceof
add a note
User Contributed Notes 5 notes
paul at paulferrett dot com ¶
13 years ago
ludvig dot ericson at gmail dot nospam dot com ¶
18 years ago
Hint:
<?php
in_array("your-interface", class_implements($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.
a dot panek at brainsware dot org ¶
9 years ago
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.
trollll23 at yahoo dot com ¶
17 years ago
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
)
sam at rmcreative dot ru ¶
4 years ago
The order of interfaces is not reliable and varies between PHP versions.
