public function setDomain( core_kernel_classes_Class $class)
    {
        $returnValue = (bool) false;
 
        if(!is_null($class)){
        	foreach($this->getDomain()->getIterator() as $domainClass){
        		if ($class->equals($domainClass)) {
        			$returnValue = true;
        			break;
        		}
        	}
        	if(!$returnValue){
        		$this->setPropertyValue($this->getProperty(OntologyRdfs::RDFS_DOMAIN), $class->getUri());
        		if(!is_null($this->domain)){
        			$this->domain->add($class);
        		}
        		$returnValue = true;
        	}
        }
        return (bool) $returnValue;
    }