public function getAvailableLanguagesByUsage( core_kernel_classes_Resource $usage)
    {
        $returnValue = array();
    	$langClass = new core_kernel_classes_Class(static::CLASS_URI_LANGUAGES);
	    $returnValue = $langClass->searchInstances(array(
            static::PROPERTY_LANGUAGE_USAGES => $usage->getUri()
	    ), array(
	    	'like' => false
	    ));
        return (array) $returnValue;
    }