Third parameter (once) cannot be recognized

[mjfcolas]

In main method:

• If number of parameters > 2, then a print usage is displayed.
  if (args.length != 2) usage();
• However, if number of parameters == 2, then a null pointer is thrown
  if (args[2].equals("once")) { return; }

Consequences:

• third parameter ("once") cannot be used
• An error will always be thrown

Here is a proposed modified main method:

• When checking if arguments are well formated:

    final String thirdArgumentExpectedValue = "once";
    // parse arguments
    final boolean wrongNumberOfArguments = args.length != 2 && args.length != 3;
    final boolean thirdArgumentInWrongFormat = args.length >= 3 && !thirdArgumentExpectedValue.equals(args[2]);
    if (wrongNumberOfArguments || thirdArgumentInWrongFormat)
    	usage();
  

-When checking presence of "once" third parameter

	if (thirdArgumentExpectedValue.equals(args[2])) {
		return;
	}