Fix UsageFormatter: inherit usage formatter for subcommands

[arkbriar]

I was so happy when I found out that JCommander has supported unix-style usage formatting. But when I use it in my project, I am confused about the design of the interface.

JCommander commander = JCommander.newBuilder()
    .setUsageFormatter(new UnixStyleUsageFormatter(/*What should I set here???*/))
    .addObject(options).build();

IMO, UsageFormatter should be stateless and should never has a constructor binding to a commander.

Moreover, usage formatter is not inherited by subcommands. So if I set the formatter of root commander to unix-like, usage() will output like

Usage: <main class> [options] [command] [command options]
  Options:
    [unix style]
  Commands:
    [default style]

So I changed almost all methods related to formatter to fix this.

• Remove field commander from DefaultUsageFormatter & UnixStyleUsageFormatter
  and adjust IUsageFormatter and its implementations.
• Modify JCommander#setUsageFormatter to set usage formatter for all
  subcommands.
• Instantiate subcommand with parent's usage formatter.
• Add @OverRide annotations on methods inherited from interface or
  super class.
• Modify accessibilty of some methods: not every method needs to be
  public.
• Revise documents.
• Modify tests.

All tests are passed.

[dozmus]

Your changes make sense to me, but CI has failed, I think this is because of Java 9?

[arkbriar]

I have removed the usage of lambda(Java 8) to avoid compilation failure. Now CI has passed.

[dozmus]

You should also update the online docs by modifying doc/index.adoc section 23.

[jgangemi]

+1

any change this could be merged and a new release cut?

[arkbriar]

Any updates? Should I change something to get this merged?

[dozmus]

@cbeust Please take a look when you can.

[PoslavskySV]

Is there any chance that this PR will be accepted soon?

[cbeust]

Apologies for not acting on this PR but each time I pull it to review it, its size forces me to reschedule it for when I have more time ahead of me...

[arkbriar]

@cbeust Sorry for the delayed response. The core change is modifying the interface IUsageFormatter by adding a new JCommander argument, which stands for the commander who request the format. For example,

    /**
     * Display the usage for this command.
     */
-   void usage(String commandName);
+   void usage(JCommander commander, String commandName);

And the other changes are just simple injecting this new parameter and make things work. Additionally, 5 out of 9 changed files are tests 😂.
Looking forward to hearing from you. If any effort I should make to get this merged, please let me know.

[dozmus]

@cbeust I don't mind reviewing it, if that is cool with you.

[cbeust]

@PureCS Of course, the more pairs of eyes, the better!

Thanks!

[cbeust]

Isn't this change a step back?

[dozmus]

It is, however it does read nicer.

[cbeust]

This is a breaking change (and there might be more in this PR, haven't fully reviewed yet).

Not a deal breaker, but if this gets merged, the major version will have to go up.

[mkarg]

@cbeust I have started a v2 branch to collect things that could go into JCommander 2.0.0. Did you find the time to finish your review, or should I start a review from scratch?

[cbeust]

Let's start from scratch.