PHP: variable name as class instance

Question

Im having a problem with using a variable as the class name when calling a static function within the class. My code is as follows:

class test {
     static function getInstance() {
         return new test();
     }
}

$className = "test";
$test = $className::getInstance();

Ive got to define the class name to a variable as the name of the class is coming from a database so i never know what class to create an instance of.

note: currently i am getting the following error:

Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM

Thanks

Funnily enough, your code works for me in PHP 5.3.1 and does not throw an error. — Pekka
– Pekka, Commented Jan 17, 2010 at 20:51
variable static classes are available in PHP 5.3+, anything lower requires call_user_func() / call_user_func_array() as mentioned by @hobodave — Owen
– Owen, Commented Jan 17, 2010 at 20:53

Community · Accepted Answer · 2023-11-17 20:42:18Z

8

$test = call_user_func(array($className, 'getInstance'));

See call_user_func and callbacks.

edited Nov 17, 2023 at 20:42

CommunityBot

11 silver badge

answered Jan 17, 2010 at 20:49

hobodave

29.4k4 gold badges74 silver badges77 bronze badges

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

1 Comment

StasM Over a year ago

Only way until 5.3 that is, in 5.3+ you can use variable classnames.

Kris · Accepted Answer · 2012-05-03 08:26:43Z

0

You could use the reflection API, that would let you do something like:

$className = 'Test';
$reflector = new ReflectionClass($className);
$method = $reflector->getMethod('getInstance');
$instance = $method->invoke(null);

or even:

$className = 'Test';
$reflector = new ReflectionClass($className);
$instance = $reflector->newInstance(); 
// or $instance = $reflector->newInstanceArgs([array]);
// or $instance = $reflector->newInstanceWithoutConstructor();

Both seem a lot cleaner to me than just interpreting the value of a string directly as a class name or using call_user_func and friends.

answered May 3, 2012 at 8:26

Kris

42.1k9 gold badges78 silver badges103 bronze badges

Collectives™ on Stack Overflow

PHP: variable name as class instance

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related