Mike,
This is a complex question and has two answers.
First, the standard enhanced vector framework (EVF) used by most readers
assumes a "pull" model: read each record. This is where the next() comes
in: readers just implement this to read the next record. But, the code
under EVF works with a
Daffodil parsing generates event callbacks to an InfosetOutputter, which is
analogous to a SAX event handler.
Drill is expecting an iterator style of calling next() to advance through
the input, i.e., Drill has the control thread and expects to do pull
parsing. At least from the code I studied in
