Null PHP Class

Null.php

<?php

class Null
{
	private static $instance;

	public function __call($name, $arguments)
	{
		if (strpos($name, 'is') === 0 || strpos($name, 'has') === 0)
		{
			return false;
		}
		else
		{
			return self::getInstance();
		}
	}

	function __toString()
	{
		return '';
	}

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

/* Demo */
$null = Null::getInstance();
var_dump($null->isActive());
var_dump($null->hasImage());
var_dump($null->getImage());
var_dump($null->getImage()->getChildImage());
var_dump($null->getImage()->getChildImage()->isActive());

echo $null->isActive() . "\n";
echo $null->hasImage() . "\n";
echo $null->getImage() . "\n";
echo $null->getImage()->getChildImage() . "\n";
echo $null->getImage()->getChildImage()->isActive() . "\n";