PHP: how can a class reference its own name?

Question

In PHP, how can a class reference its own name?

For example, what would the method look like to do this?

Dog::sayOwnClassName();
//echos "Dog";

Update

I see that everyone is saying get_class($this). But that's not correct. That would work if I were creating an instance of Dog. I'm asking about calling a method of the Dog class itself. If Dog extends Mammal, then a call to get_class($this) inside the Dog class will return 'Mammal.'.

In other words:

I'm not asking "what's the class of the Dog class," to which the answer is, "the Dog class is a member of the Mammal class."
I'm also not asking "given an instance of Dog the dog class (called Rover), what is its class?", to which the answer is "Dog."
What I'm asking is, "can the Dog class itself tell me 'my name is Dog?'"

For example:

class Mammal {    
  public function find_by_id($id){
    $query = "SELECT * FROM " . $myclass . " WHERE `id` = " . $id;
    //(etc)
    return $matching_object;
  }
}

class Dog extends Mammal {
//find_by_id method should know to do a SELECT from Dog table     
}

Update 2

Yacoby's suggestion of get_called_class() was correct. Here's how it works in the example I gave.

class Mammal {    
      public function find_by_id($id){
        $myclass = get_called_class();
        $query = "SELECT * FROM " . $myclass . " WHERE `id` = " . $id;
        //(etc)
        return $matching_object;
      }
    }

    class Dog extends Mammal {
    //find_by_id knows to do a SELECT from Dog table
    //and will return the correct dog object     
    }

danronmoon · Accepted Answer · 2020-11-28 13:20:49Z

30

Three options, get_called_class(), get_class() or the magic constant __CLASS__

Of those three get_called_class() is the one you want when dealing using a static function, although unfortuantely it does have a requirement of a PHP version of at least 5.3.0

get_called_class()

If you need to get the class in a static function when the class may be derived it is slightly different as self is resolved to the class name where it was placed (See Limitations of self::). To work around this issue you need to use the function from PHP 5.3.0 get_called_class().

If you cannot use PHP 5.3.0 or greater you may find you cannot make the function static and still have it achieve the results you want.

get_class()

get_class() returns the name of the actual class that the object is, irrespective of where the function call is.

class Animal{
     public function sayOwnClassName(){
         echo get_class($this);
     }
}

class Dog extends Animal{
}


$d = new Dog();
$d->sayOwnClassName(); //echos Dog

$a = new Animal();
$a->sayOwnClassName(); //echos Animal

get_class can also be used without a parameter, which would at first glance seem to indicate it would with static functions (as there is no need to pass $this), however when used without a parameter it works in the same way as __CLASS__

class Animal{
     public static function sayOwnClassName(){
         echo get_class();
     }
}

class Dog extends Animal{
}


Dog::sayOwnClassName(); //echos Animal
Animal::sayOwnClassName(); //echos Animal

CLASS

__CLASS__ always expands to the name of the class where __CLASS__ was resolved, even when inheritance is taken into account.

class Animal{
     public function sayOwnClassName(){
         echo __CLASS__; //will always expand to Animal
     }
}

class Dog extends Animal{
}

$d = new Dog();
$d->sayOwnClassName(); //echos Animal

$a = new Animal();
$a->sayOwnClassName(); //echos Animal

edited Nov 28, 2020 at 13:20

danronmoon

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answered Apr 7, 2010 at 16:23

Yacoby

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5 Comments

Gordon Over a year ago

+1 for mentioning the magic constant in addition to get_class and the better examples

Nathan Long Over a year ago

Yacoby - you're instantiating Dog. I'm not.

Yacoby Over a year ago

@Nathan I missed that complexity, my apologies. I have added some more information at the bottom of my answer.

Nathan Long Over a year ago

@Yacoby - great! Thanks - that did the trick. Would you mind editing your answer to just show the get_called_class() part so that people who find this later get straight to that?

Yacoby Over a year ago

@Nathan Done (Well not quite, but is shows the get_called_class part far more clearly)

Amy B · Accepted Answer · 2010-04-07 16:23:26Z

2

echo get_class($this);

answered Apr 7, 2010 at 16:23

Amy B

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1 Comment

Nathan Long Over a year ago

I'm not instantiating Dog - I'm using a class-level method.

Syntax Error · Accepted Answer · 2010-04-07 16:24:28Z

1

Well, there's get_class($Object)

Then there's __CLASS__ when used within a class

Or you could make a method that would return __CLASS__

answered Apr 7, 2010 at 16:24

Syntax Error

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Comments

knittl · Accepted Answer · 2010-04-07 16:44:28Z

1

use the magic constant __CLASS__

answered Apr 7, 2010 at 16:44

knittl

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Comments

Benedict Cohen · Accepted Answer · 2010-04-07 16:24:14Z

0

public function sayClassName()
{
    echo get_class($this);
}

get_class() php docs

answered Apr 7, 2010 at 16:24

Benedict Cohen

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PHP: how can a class reference its own name?

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get_called_class()

get_class()

CLASS

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5 Answers 5

get_called_class()

get_class()

__CLASS__

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