public void changeOwner(String user, String fileId, String newOwner) { // Find what is the current permission of the new owner on the file Permission newOwnerPermission = null; PermissionList permissionList = RetriableTask.execute(new DrivePermissionListTask(drive.permissions().list(fileId))); newOwnerPermission = findPermission(permissionList, newOwner); if (newOwnerPermission == null) { // New owner is not in the list, we need to insert it newOwnerPermission = new Permission(); newOwnerPermission.setValue(newOwner); newOwnerPermission.setType("user"); newOwnerPermission.setRole("owner"); Drive.Permissions.Insert insert = drive.permissions().insert(fileId, newOwnerPermission); RetriableTask.execute(new DrivePermissionInsertTask(insert)); } else { // New owner is already in the list, update the existing permission newOwnerPermission.setRole("owner"); Drive.Permissions.Update update = drive.permissions().update(fileId, newOwnerPermission.getId(), newOwnerPermission); update.setTransferOwnership(true); RetriableTask.execute(new DrivePermissionUpdateTask(update)); } }
public class RetriableTask implements Callable { [...] private final Callable task; [...] @Override public T call() { T result = null; try { startTime = System.currentTimeMillis(); result = task.call(); } catch (NonFatalErrorException e) { if (numberOfTriesLeft > 0) { // Wait some time, using exponential back-off in case of multiple attempts Thread.sleep(getWaitTime()); // Try again result = call(); } else { // Too many failed attempts: now this is a fatal error throw new RetryException(); } } catch (FatalErrorException e) { // This one should not be retried Throwables.propagate(e); } return result; }
