code: public void addRequestHandler(String host, String firstPath, 
  			RequestHandler requestHandler) {
  		String key = hostPathToKey(host, firstPath);
  		if (pathMap.containsKey(key)) {
  			LOGGER.warning("Duplicate port:path map for " + port +
  					":" + key);
  		} else {
  			pathMap.put(key, requestHandler);
  			if (LOGGER.isLoggable(Level.FINE)) {
  				LOGGER.fine("Registered requestHandler(port/host/path) (" +
  						port + "/" + host + "/" + firstPath + "): " + key);
  			}
  		}
  	}
docs: Register the RequestHandler to accept requests for the given host and
  port.
  @param host the HTTP 1.1 "Host" header which the RequestHandler should
  match. If null, the RequestHandler matches any "Host" header value.
  @param firstPath the first path of the GET request path which the
  RequestHandler should match. This is the first path AFTER the name the
  Wayback webapp is deployed under. If null, the RequestHandler matches
  all paths.
  @param requestHandler The RequestHandler to register.