BPEL - File Processing - Sorting and Customized Order

BPEL file processing
File Sorting:
http://docs.oracle.com/cd/E21764_01/integration.1111/e10231/adptr_file.htm#BABBIJCJ

File Processing Order:
https://blogs.oracle.com/adapters/entry/controlling_the_order_in_which_files_get_processed