Github user ottobackwards commented on the issue:
https://github.com/apache/metron/pull/1033
+1
I will say, that the exception building facilities and builders should be
publicly exposed as part of stellar as a follow on. As part of my own antlr
work on the syslog stuff, I am kind of fond of being able to allow expansion by
deriving new listeners and visitors with separate implementations, the
exception builders would be nice to have with that, if you follow.---
