PHP and singletons again.

Question

Hi, i have code:

class ConfigReader
{
    private static $instance = NULL;
    protected $configData = array();                                                                        

    public function getInstance()
    {
        if( self::$instance == NULL )
        {
            self::$instance == new ConfigReader();
        }
        return self::$instance;
    }

    public function getConfigValue( $getName )
    {
        echo 'In function';
    }

    private function __construct()
    {
        $this->configData = %READ_FROM_DATABASE%;
    }

    private function __clone() {}
}

And for:

var_dump( ConfigReader::getInstance() )

I got: NULL

I broke by brains... Help me, please.

Answer 1

Just a typo: self::$instance == new ConfigReader() contains == instead of =

Answer 2

The method getInstance() should also be static.

Answer 3

In the method getInstance, you should use only one '=' : you want to make an assignation, and not a compatison :

self::$instance = new ConfigReader();

Instead of

self::$instance == new ConfigReader();

And that method should be declared as static, as you are using it as a static method :

public static function getInstance()
{
    if( self::$instance == NULL )
    {
        self::$instance = new ConfigReader();
    }
    return self::$instance;
}

Weth these two modifications, it should work ;-)