public boolean cancelTransfer(String username,String submissionID){
  if (cancelUpload(username,submissionID))   return true;
  return cancelDownload(username,submissionID);
}

public boolean cancelTransfer ( String username , String submissionID ) { if ( cancelUpload ( username , submissionID ) ) return true ; return cancelDownload ( username , submissionID ) ; }
cancels a transfer for the user with the given submissionid if existing .
