code: public void lockField(EntryField entryField, String reason) {
                  locking.put(entryField, reason);
                  if (entryField == EntryField.ORIGINATOR) {
                          locking.put(EntryField.ORIGINATOR_CANDIDATES, reason);
                  }
          }
docs: Locks a field of the log entry.<br>
  Locked fields cannot be altered anymore. If the originator field is
  locked, then the originator candidates field is locked as well, since
  changing the candidates also changes the originator (consistency).
  
  @param entryField
  @param reason