How can I call a static method on a variable class?

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I'm trying to make some kind of function that loads and instantiates a class from a given variable. Something like this:

<?php
function loadClass($class) {
  $sClassPath = SYSPATH."/classes/{$class}.php";
  if (file_exists($sClassPath)) {
    require_once($sClassPath);
    $class = $class::getInstance();
  }
}
?>

If I use it like this:

<?php
  loadClass('session');
?>

It should include and instantiate the session class.

BTW: the static getInstance function comes from this code:

<?php
  function getCallingClass() {
    $backtrace = debug_backtrace();
    $method    = $backtrace[1]['function'];
    $file      = file($backtrace[1]['file']);
    $line      = $file[($backtrace[1]['line'] - 1)];
    $class     = trim(preg_replace("/^.+?([A-Za-z0-9_]*)::{$method}\(.*$/s", "\\1\\2", $line));

    if(! class_exists($class)) {
      return false;
    } return $class;
  }

  class Core {

    protected static $instances = array();

    public static function getInstance() {
      $class = getCallingClass();

      if (!isset(self::$instances[$class])) {
        self::$instances[$class] = new $class();
      } return self::$instances[$class];
    }

  }

?>

The thing is that right now the way to use the functions in a class is this:

<?php
  $session = session::getInstance();
?>

But now I want to build that into a function so that I never again have to use that line of code. I just say loadClass('session'); and than I can use $session->blablablafunction();

instance function class oop php
6 Answers

You can use call_user_func():

$class = call_user_func(array($class, 'getInstance'));

The first argument is a callback type containing the classname and method name in this case.

user_241810
kodisha_135490

It looks like you are fighting PHP's current implementation static binding, which is why you are jumping through hoops with getCallingClass. I can tell you from experience, you should probably abandon trying to put instantiation in a parent class through a static method. It will cause you more problems in the end. PHP 5.3 will implement "late static binding" and should solve your problem, but that obviously doesn't help now.

You are probably better off using the autoload functionality mentioned by kodisha combined with a solid Singleton implementation. I'm not sure if your goal is syntactic sugar or not, but it think you will do better in the long run to steer clear of trying to save a few characters.

Barrett_Conrad_12270

Off the top of my head, needs testing, validation etc:

<?php

    function loadClass($className) {
        if (is_object($GLOBALS[$className]))
            return;

        $sClassPath = SYSPATH."/classes/{$className}.php";
        if (file_exists($sClassPath)) {
            require_once($sClassPath);

            $reflect = new ReflectionClass($className);
            $classObj = $reflect->newInstanceArgs();
            $GLOBALS[$className] = $classObj;
        }
    }

?>
user_352920
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