Accepting a single main parameter doesn't appear to be possible

We only support opening a single case at a time, so I figured I would just use this for accepting the location as the main parameter:

@Parameter(descriptionKey = "DesktopMainArguments.docLocation")
public File docLocation;

Attempting to parse then throws the following exception:

com.beust.jcommander.ParameterException: Main parameter field public java.io.File com.acme.main.MainArguments.docLocation needs to be of type List, not class java.io.File

I’m sure I could change it to a list, but then I would have to put in boilerplate to check that the user hasn’t specified more than one. Is there a proper way to do this directly? Because I can’t seem to find it in the examples or in the API.

I thought validation might be the way to do it, but I suspect I was wrong about that because the validator receives the original command-line string, not the final converted object.

[rtomsick]

@trejkaz has a valid point.

Intuitively, if I write:

@Parameter(arity = 1)
public List<String> foo;

I would expect at most one entry in foo. That doesn’t happen now (in direct contradiction of the JavaDoc, FWIW.)

Even better would be allowing @Parameter(arity = 1) to apply to any type, not just List.

Yes, it is possible to work around this now, but DRY is a valid concern. There’s no good reason to make the caller write the same validation code every time for what is actually a pretty reasonable use case…

[walles]

Thanks for fixing this @cbeust!

I just tried this in 1.72 and it works like a charm 😃