Hello,
It looks like they did not document the Hadoop specific information for the Input adapters. They only put this information into the Output Adapters. I have logged a documentation bug for this:
762524 - Hadoop support not documented on Input Adapters
See if the Hadoop specific information about the 'Dir' parameter for the Output Adapter gives you the information you need to proceed:
File/Hadoop CSV Output Adapter Configuration
Thanks,
Neal