Switch to Spoon

[chrismwendt]

Why switch from JavaParser to Spoon?

• Cross-file defs/refs currently don't work, and my attempt to make it work using JavaParser was unsuccessful Cross-file j2d/refs #1
• https://github.com/microsoft/lsif-java seems to be 10+x slower than JavaParser (I don't know why)
• Spoon is very popular and I wanted another data point in this design space (speed, features, etc.)
• Spoon seems to be comparable to JavaParser in speed

Spoon is another Java source code parser/analysis library. My personal observations have been that compared to JavaParser, Spoon:

• Has nicer docs for getting started http://spoon.gforge.inria.fr/index.html
• Has a sane API
• Has built-in Maven support
• Is built on Eclipse JDT

I think cross-repo can be done using Spoon because Spoon tries to provide "weak" references to symbols outside of the current project http://spoon.gforge.inria.fr/references.html and I've seen Unknown file when trying to get the definition of something like String. We could attach a moniker right there.

TODO

• Clean up the code a bit (it's in a raw WIP state right now)