Question

I have following setup.

index.php

   require_once "common.php";
   ...

common.php

   ...
   $obj = new MyClass;
   require_once "config.php"
   ...

config.php

   ...
   require_once "settings.php";
   ...

settings.php

   $obj->dostuff = true;
   ...

When i open index.php i get: Strict Standards: Creating default object from empty value in settings.php on 3

If i put $obj->dostuff = true; inside config.php it does not produce error message.

Can someone explain why i get this error? I am not asking how to fix it just understand why.

EDIT: My bad i had 2 config.php classes for each part of site and i only changed something in one of them leaving old include order in another now it works fine after it all loads in correct order.

Answer 1

If $obj is meant to be a system wide globally accessible object, you can you use the singleton pattern to access from anywhere:

class MyClass
{
    protected static $_instance;

    static function getInstance()
    {
        if (null === self::$_instance) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }
}

You can then create your methods in this class. To get the object itself simply call:

$obj = MyClass::getInstance();

Additionally, if you just want to call one of its methods but theres no need to return anything:

MyClass::getInstance()->objectMethod();

I find this to be a very efficient way to organize integral singleton based system wide operations.

In practice, my project uses this to get configuration from anywhere in the system:

class syConfig
{
    protected static $_instance;

    private $_config;

    static function getInstance()
    {
        if (null === self::$_instance) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    public function load($xmlString)
    {
        $xml = simplexml_load_string($xmlString);
        $this->_config = $xml;
    }

    public function getConfig()
    {
        return $this->_config;
    }
}