when composing commands from other commands we need to be able to hide inputs in the base command

right now in fabric8-forge for creating new projects; we reuse the project-new command; but we've added a hack to override the targetLocation property; so that the user doesn't' get to pick that - we want to hide that completely from the user. Meanwhile the project-new-git logical wrapper command defaults this value, uses a canonical temporary folder and then stores the new project in git (instead of a local file system on the developers laptop).

It would be good to port this code to be pure vanilla forge commands that could be reused from the CLI / eclipse / IDEA too. To do this we'd need to be able to wrap the project-new command with a project-new-git command that then hides the input for the "targetLocation" property (defaulting the value so that the inner project-new command can work as before; then the outer command, project-new-git can do the git thingy.

I've not had chance to experiment a way to do this nicely; maybe using a proxy command or something and using a temporary UIBuilder class that we pass to the delegate inner command to build its stuff; so that the outer command can remove things from the real UIBuilder etc - but I figured it'd be nice for this kind of thing to be a standard feature to make commands easier to combine and compose. It'd also make it easier for us to move the project-new-git command back into the main forge project (though I guess thats kinda complex as the project-new-git command would probably want to create a local copy too on the users desktop when not running in a REST service - so maybe this kinda thing is highly environment specific?)