protected function validateConf()
    {
        foreach ($this->getRequiredConfParams() as $name => $type) {
            if (!isset($this->params[$name]) || gettype($this->params[$name]) !== $type) {
                throw new Exception("Parameter '{$name}' missing or not of type '{$type}' (adapter '{$this->name}')");
            }
            if (substr($name, -5) == '_path') {
                $path = $this->getConfParam($name);
                if (!is_file($path)) {
                    throw new Exception("File not found: $path");
                }
            }
        }
    }