public function get($key) {

        if (!isset($this->hashmap[$key])) { return null; }

        $node = $this->hashmap[$key];
        if (count($this->hashmap) == 1) { return $node->getData(); }

        // refresh the access
        $this->detach($node);
        $this->attach($this->head, $node);

        return $node->getData();
    }