jcommander: Need way to automatically show usage if required params are missing

Currently if you specify help = true in a parameter, exceptions are suppressed. However, you then have to manually check for required parameters not being set.

It would be great if there were a way to prevent exceptions from being thrown on missing required parameters, but print the usage text instead. Maybe in addition to adding help = true to a help parameter, you could also specify usage = true, and if a parameter is missing, even if the help option was not given on the commandline, JCommander could set the help parameter value to true, so that the usage text is displayed?

About this issue

Original URL
State: closed
Created 7 years ago
Comments: 16 (6 by maintainers)

Most upvoted comments

How about adding the JCommander instance to the ParameterException?

– Cédric

On Fri, Mar 17, 2017 at 10:35 PM, Luke Hutchison notifications@github.com wrote:

The reason the current pattern is problematic is that you don’t have a JCommander reference if the constructor throws an exception, so you can’t call the usage() method if there is a missing parameter, unless there is a help = true parameter. But if there is a help = true parameter, you don’t get built-in required parameter checking. It’s not possible currently to get both built-in required parameter checking and be able to display usage info if there is a missing required parameter.

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cbeust on Mar 18, 2017