通过运行时反射确定不在标准库（Java或Scala）中的基类

Question

I'm generating GraphQL definitions from Scala types but can't find anything in the runtime reflection API to only get base classes that are "user defined" ie not part of the Scala or Java standard library.

As of right now I just have a set of the ones I know pops up eg Any , Object and about 8 others. Those are only in the list because they're what showed up when I was writing unit tests. Ideally I don't want a manual list, seems brittle as new types are added it'll probably break.

I don't know if this is possible with macros but that's not an option. After experimenting with macros there were too many bugs around it, including it causing the compiler to crash and the fix for that bug is suppose to be in the latest zinc but I can't use it because I'm using Gradle which can only use the 0.xx zinc series due to namespace changes in the 1.x series.

So all that being said, does anyone know if there's a means of determining baseclasses of a type that are not from the standard libraries?

Answer 1

I don't think such a feature exist and even should exist. Particularly I don't think that the term "standard library" is really defined well enough in the context of your problem. I mean why exactly it should exclude classes from the standard library but not from some other popular libraries you depend on? And there are some quite complicated types in the standard library as well (eg java.text.DateFormat or org.w3c.dom.Document ). Yes, you probably don't expose them right now but this is only for now.

I think that the proper way is to have an explicit white list of all base classes and/or packages that you want to expose as a part of your API contract and use it for filtering. You might also try to use a black list (like java.* , javax.* , scala.* ) to filter out the "standard library" and it might work for some time but I still don't think this is a good idea.