title: How to detect changes in Google Spreadsheet? Java
body: <p>The spreadsheet holds events and my code has a linked list of these events organized by date.
  However my code only reads the spreadsheet once.
  So if the spreadsheet is every changed (added a row, deleted a row) my code doesn't know.
  I'd like my spreadsheet to somehow notify my code that a change has been made.
  Else I guess the other option is to check for any changes once a day with something like a while loop.
  Thanks!</p>