php check if method overridden in child class

Question

Is it possible to check whether or not a method has been overridden by a child class in PHP?

<!-- language: lang-php -->

class foo {
    protected $url;
    protected $name;
    protected $id;

    var $baz;

    function __construct($name, $id, $url) {
        $this->name = $name;
        $this->id = $id;
        $this->url = $url;
    }

    function createTable($data) {
        // do default actions
    }
}

Child class:

class bar extends foo {
    public $goo;

    public function createTable($data) {
        // different code here
    }
}

When iterating through an array of objects defined as members of this class, how can I check which of the objects has the new method as opposed to the old one? Does a function such as method_overridden(mixed $object, string $method name) exist?

foreach ($objects as $ob) {
    if (method_overridden($ob, "createTable")) {
        // stuff that should only happen if this method is overridden
    }
    $ob->createTable($dataset);
}

I am aware of the template method pattern, but let's say I want the control of the program to be separate from the class and the methods themselves. I would need a function such as method_overridden to accomplish this.

Overloaded, or overridden? I thought PHP didn't have method overloading — Damien Pirsy
– Damien Pirsy, Commented Jul 15, 2013 at 20:23
You could try this: php.net/manual/en/reflectionclass.hasmethod.php — Damien Pirsy
– Damien Pirsy, Commented Jul 15, 2013 at 20:26
If your design is dependant on knowing how classes have overridden particular methods, then there's something seriously wrong with your design. The whole idea behind OO is that you can send a message to an object and it's up to the object to handle it in an appropriate way. The calling code shouldn't care what implementation is being called or how its message is being dealt with. — GordonM
– GordonM, Commented Nov 7, 2013 at 9:39

4levels · Accepted Answer · 2019-07-31 15:44:38Z

25

Check if the declaring class matches the class of the object:

$reflector = new \ReflectionMethod($ob, 'createTable');
$isProto = ($reflector->getDeclaringClass()->getName() !== get_class($ob));

PHP Manual links:

edited Jul 31, 2019 at 15:44

4levels

3,2742 gold badges25 silver badges22 bronze badges

answered Jul 15, 2013 at 20:30

nice ass

16.8k8 gold badges54 silver badges92 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Joey Over a year ago

This is certainly the way I want to go about it, but I have a question: for what reason are you using the namespace operator before ReflectionMethod? Is it to ensure that method is being called from the global namespace instead of accidentally calling a method of the same name defined in a more local scope?

nice ass Over a year ago

It's probably not needed in your case. If the code above is under a namespace, you would need to either import the ReflectionMethod class, or access it with global namespace prefix (`\`). I'm just making sure this situation is handled :)

Skeets Over a year ago

This can be done with class properties as well. Just use \ReflectionProperty() instead.

Philipp · Accepted Answer · 2015-01-07 16:00:15Z

2

To get this information, you have to use ReflectionClass. You could try getMethod and check the class name of the method.

$class = new ReflectionClass($this);
$method = $class->getMethod("yourMethod");
if ($method->class == 'classname') {
    //.. do something
}

But keep in mind, that reflection isn't very fast, so be careful with usage.

edited Jan 7, 2015 at 16:00

answered Jul 15, 2013 at 20:30

Philipp

15.7k4 gold badges38 silver badges54 bronze badges

1 Comment

Ikar Pohorský Over a year ago

In PHP 5.5.20 the $method['class'] gave me: Cannot use object of type ReflectionMethod as array. The $method->class worked just fine.

Collectives™ on Stack Overflow

php check if method overridden in child class

2 Answers 2

3 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related