Users can botch program input in more ways than you could ever
imagine. To detect an error, check JSAPResult.success()
after parsing the command line. It will return false if there were any
problems.
Once you detect a problem, you have a number of options:
Display program usage (see HelloWorld_5
example)
Display help information (see HelloWorld_6
example)
Display messages specific to the user's errors (see
HelloWorld_7 example)
Obtain a list of parameter IDs for the problematic items through
JSAPResult.getBadParameterIDIterator(). Then
obtain the individual exceptions for each ID through
JSAPResult.getExceptionIterator(String id)
and related methods. After that, you're on your own.
Any combination of the above.
If you have used SimpleJSAP error handling is
largely simplified, as it will be handled automatically. Remember just to
call messagePrinted() after parsing and take
appropriate action.