You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: filehandler.rb
    path of file: ./repos/truffleruby/test/mri/tests/lib/webrick/httpservlet
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
#
# filehandler.rb -- FileHandler Module
#
# Author: IPR -- Internet Programming with Ruby -- writers
# Copyright (c) 2001 TAKAHASHI Masayoshi, GOTOU Yuuz
    
      def exec_handler(req, res)
        raise HTTPStatus::NotFound, "`#{req.path}' not found." unless @root
        if set_filename(req, res)
          handler = get_handler(req, res)
          call_callback(:HandlerCallback, req, res)
          h = handler.get_instance(@config, res.filename)
          h.service(req, res)
          return true
        end