public static function getHandlers()
    {
        $handlers = array();
        $handlerList = self::getHandlerList();
        $cacheHash = md5( serialize( $handlerList ) );
        
        if ( isset( $GLOBALS['eZHTTPCacheManager_' . $cacheHash] ) )
            return $GLOBALS['eZHTTPCacheManager_' . $cacheHash];
        
        foreach ( $handlerList as $handler )
        {
            $object = new $handler;
            if ( $object instanceof eZHTTPCacheManagerInterface )
                $handlers[] = $object;
        }
        
        $GLOBALS['eZHTTPCacheManager_' . $cacheHash] = $handlers;
        
        return $handlers;
    }