Hide the generated SpdxId class from the public API by marking it as internal

[TheMrMilchmann]

This is not used anywhere in the public API and probably should not be exposed.

This is based on #397.

[JakeWharton]

These are public for usage in build files to pass to our allow-prefixed APIs. Should probably be generating Java though so we stay usable from Groovy.

[TheMrMilchmann]

Thanks for clarifying, this makes perfect sense.

In this case, wouldn't it make sense to add overloads to allow functions that take a SpdxId instead of requiring allow(SpdxId.Apache_20.id)?

Should probably be generating Java though so we stay usable from Groovy.

Are you referring to API ergonomics? This could probably be solved by using @JvmField, no?

[JakeWharton]

Probably? Maybe @hfhbd remembers what was next. I did inadvertently sit on the PR to add the feature for too long so we probably lost any planned follow-ups.

[hfhbd]

Yeah, I had not enough time.

In this case, wouldn't it make sense to add overloads to allow functions that take a SpdxId instead of requiring allow(SpdxId.Apache_20.id)?

That is the idea.