code: public ChainedVirtualHostBuilder withVirtualHost(String hostnamePattern) {
          final ChainedVirtualHostBuilder virtualHostBuilder =
                  new ChainedVirtualHostBuilder(hostnamePattern, this);
          virtualHostBuilders.add(virtualHostBuilder);
          return virtualHostBuilder;
      }
docs: Adds the <a href="https://en.wikipedia.org/wiki/Virtual_hosting#Name-based">name-based virtual host</a>
  specified by {@link VirtualHost}.
  
  @param hostnamePattern virtual host name regular expression
  @return {@link VirtualHostBuilder} for build the virtual host