code: public VirtualHost getVirtualHost(String targetHost) throws WebAppHostNotFoundException {
          Iterator i = requestMapper.targetMappings();
  
          while (i.hasNext()) {
              RequestProcessor rp = (RequestProcessor) i.next();
              if (rp instanceof VirtualHost) {
                  VirtualHost vHost = (VirtualHost) rp;
                  if (targetHost.equalsIgnoreCase(vHost.getName()))
                      return vHost;
              }
          }
  
          return null;
      }
docs: Method getVirtualHost. Returns null if the input name does not
  match any configured host.
  
  @param targetHost
  @return VirtualHost
  
  This method is not to be used in any request processing as it
  is not optimized for performance
  @throws WebAppHostNotFoundException