kafka08 simple consumer firehose

I also changed druid-api package, added a method "public long getLastOffsetCommitTime(); " in "interface Firehose". The  way to call new commit method is hacked by using reflection,  quick and dirty way, need to refactor to add some method to interface. 
it seems to only support adding files, 
use FixedFileArrayList<File> and avoid the typcast ?