PHP Static Calls from a Object

Question

I have a PHP class method which is using a static function from with a another class. How do i enable that static function to modify variables within the calling class.. Example as follows:

PARENT:

class sys_core
{
   public $test = 'no';

   // --------------------
   public function __construct()
   {
   }

   // --------------------
   public function init()
   {
      sys_loader::load_config('123');
      print $this->test;
   }

   // --------------------
   // --------------------
   // --------------------
   // --------------------
   // --------------------

} // END Class

STATIC CLASS

class sys_loader
{
   private $registry = array();

   // --------------------
   public static function load_config($file)
   {
      $this->test = 'yes';
   }

   // --------------------
   // --------------------
   // --------------------
   // --------------------

} // END Class

ERROR:

Fatal error: Using $this when not in object context

You can not access object variables from static context. Just do a standard call, not a static call. — hakre
– hakre, Commented Jan 2, 2012 at 17:05

iletras · Accepted Answer · 2012-01-02 18:34:45Z

As I see it, sys_loader can modify sys_core's $test 3 ways:

1) sys_loader is passed a reference to sys_core->test,
2) sys_loader returns a new value for it or
3) equip sys_core with a setter for $test and pass sys_loader a reference to sys_core.
With that reference, sys_loader can access whatever variables and functions sys_core allows.

Here are the bits I changed/added to make #3 work:

Example use:

$sc = new sys_core();
$sc->setConfigFile('123');
$sc->init();

Output:
123yes

class sys_core

// new
private $configFile = null;

// new
function getConfigFile() {
  return $this->configFile;
}

// new
function setConfigFile($value) {
  $this->configFile = $value;
}

// new
function setTest($value) {
  $this->test = $value;
}


public function init()
{
// sys_loader::load_config('123');
  sys_loader::load_config($this);
  print $this->test;
}

class sys_loader

// public static function load_config($file)
public static function load_config($caller)
{
// $this->test = 'yes';
  $caller->setTest('yes');
// new, example
  $config = $caller->getConfigFile();
// new, example
  echo $config;
}

C-F · Accepted Answer · 2012-01-02 17:45:55Z

1

If it helps, you can pass a reference to your sys_core instance as a parameter to the sys_loader::load_config method:

class sys_core
{...
    public function init()
    {
       sys_loader::load_config('123', $this);
       print $this->test;
    }    
 ...
}

class sys_loader
{
  ...
   // --------------------
   public static function load_config($file, $core)
   {
      $core->test = 'yes';
   }
 ...
}

answered Jan 2, 2012 at 17:45

C-F

1,81619 silver badges28 bronze badges

Comments

user656925 · Accepted Answer · 2012-01-02 17:09:46Z

0

You can access any public member outside of that class, private members can only be accessed by the class itself, and protected members can be accessed by sub-classes.

self is used for static members...one per class.

this is used for non-static members...one per instance.

answered Jan 2, 2012 at 17:09

user656925

Comments

Christian Neverdal · Accepted Answer · 2012-01-02 17:13:31Z

0

You can't. By definition, static means not tied to any object. (What are you trying to accomplish here?)

Static methods are per class, they can take in parameters and modify static variables. Figure out what you need, draw a diagram, and implement it.

edited Jan 2, 2012 at 17:13

answered Jan 2, 2012 at 17:04

Christian Neverdal

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4 Comments

Lee Over a year ago

I want to have a class act as a container which contains all my loading functions.. So my CORE class will use functions from within my loader class to require in configs (in this instance), placing the contents into a registry within the core.

Lee Over a year ago

Just to add another note.. There is no need to create objects out of the static classes as i just require functions from them. I am using classes for organisation only really.

Christian Neverdal Over a year ago

Updated answer, see if it helps. If you really understand the static/non-static concept, then solving your problem should be straightforward.

hakre Over a year ago

@Lee: If you only need functions, you should only use functions. I have the feeling you're making your life needlessly complicated. Set the variables into a global object or array, and just tell a loader function to where load that into. That works as well with static variables and static class functions.

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