public function getProperties()
    {
        if ($this->properties === null) {
            // lazy load class properties list
            $this->properties = array();
            foreach ($this->node->stmts as $stmt) {
                if ($stmt instanceof Node\Stmt\Property) {
                    $this->properties[] = new PropertyModel($this, $stmt);
                }
            }
        }
        return array_values($this->properties);
    }