code: private String findLongestCommand(String prefix) {
  		String result = methodTargets.keySet().stream()
  				.filter(command -> prefix.equals(command) || prefix.startsWith(command + " "))
  				.reduce("", (c1, c2) -> c1.length() > c2.length() ? c1 : c2);
  		return "".equals(result) ? null : result;
  	}
docs: Returns the longest command that can be matched as first word(s) in the given buffer.
  
  @return a valid command name, or {@literal null} if none matched