How to use

deleteFileIfExists

method

in

alluxio.util.UnderFileSystemUtils

 /**
  * Updates the checkpoint to the specified URI.
  *
  * @param location the location of the new checkpoint
  */
 public void update(URI location) {
  try {
   if (mUfs.isFile(mCheckpoint.toString())) {
    UnderFileSystemUtils.deleteFileIfExists(mUfs, mTempBackupCheckpoint.toString());
    UnderFileSystemUtils.deleteFileIfExists(mUfs, mBackupCheckpoint.toString());
    // Rename in two steps so that we never have identical mCheckpointPath and
    // mBackupCheckpointPath. This is a concern since UFS may implement rename as copy + delete.
    mUfs.renameFile(mCheckpoint.toString(), mTempBackupCheckpoint.toString());
    mUfs.renameFile(mTempBackupCheckpoint.toString(), mBackupCheckpoint.toString());
    LOG.info("Backed up the checkpoint file to {}", mBackupCheckpoint.toString());
   }
   mUfs.renameFile(location.getPath(), mCheckpoint.toString());
   LOG.info("Renamed the checkpoint file from {} to {}", location,
     mCheckpoint.toString());

   // The checkpoint already reflects the information in the completed logs.
   mWriter.deleteCompletedLogs();
   UnderFileSystemUtils.deleteFileIfExists(mUfs, mBackupCheckpoint.toString());
  } catch (IOException e) {
   throw new RuntimeException(e);
  }
 }
}

@Override
public synchronized JournalOutputStream getCheckpointOutputStream(long latestSequenceNumber)
  throws IOException {
 if (mCheckpointOutputStream == null) {
  mCheckpointManager.recover();
  LOG.info("Creating tmp checkpoint file: {}", mTempCheckpoint);
  if (!mUfs.isDirectory(mJournal.getLocation().toString())) {
   LOG.info("Creating journal folder: {}", mJournal.getLocation());
   mUfs.mkdirs(mJournal.getLocation().toString());
  }
  mNextEntrySequenceNumber = latestSequenceNumber + 1;
  LOG.info("Latest journal sequence number: {} Next journal sequence number: {}",
    latestSequenceNumber, mNextEntrySequenceNumber);
  UnderFileSystemUtils.deleteFileIfExists(mUfs, mTempCheckpoint.toString());
  mCheckpointOutputStream = new CheckpointOutputStream(
    new DataOutputStream(mUfs.create(mTempCheckpoint.toString())));
 }
 return mCheckpointOutputStream;
}

UnderFileSystemUtils.deleteFileIfExists(mUfs, mCheckpoint.toString());
mUfs.renameFile(mTempBackupCheckpoint.toString(), mCheckpoint.toString());

String ufsBlockPath = alluxio.worker.BlockUtils.getUfsBlockPath(ufsClient, blockId);
try (CloseableResource<UnderFileSystem> ufsResource = ufsClient.acquireUfsResource()) {
 alluxio.util.UnderFileSystemUtils.deleteFileIfExists(ufsResource.get(), ufsBlockPath);
} catch (Exception e) {
 LOG.warn("Failed to clean up staging UFS block file {}", ufsBlockPath, e.getMessage());

 /**
  * Updates the checkpoint to the specified URI.
  *
  * @param location the location of the new checkpoint
  */
 public void update(URI location) {
  try {
   if (mUfs.isFile(mCheckpoint.toString())) {
    UnderFileSystemUtils.deleteFileIfExists(mUfs, mTempBackupCheckpoint.toString());
    UnderFileSystemUtils.deleteFileIfExists(mUfs, mBackupCheckpoint.toString());
    // Rename in two steps so that we never have identical mCheckpointPath and
    // mBackupCheckpointPath. This is a concern since UFS may implement rename as copy + delete.
    mUfs.renameFile(mCheckpoint.toString(), mTempBackupCheckpoint.toString());
    mUfs.renameFile(mTempBackupCheckpoint.toString(), mBackupCheckpoint.toString());
    LOG.info("Backed up the checkpoint file to {}", mBackupCheckpoint.toString());
   }
   mUfs.renameFile(location.getPath(), mCheckpoint.toString());
   LOG.info("Renamed the checkpoint file from {} to {}", location,
     mCheckpoint.toString());

   // The checkpoint already reflects the information in the completed logs.
   mWriter.deleteCompletedLogs();
   UnderFileSystemUtils.deleteFileIfExists(mUfs, mBackupCheckpoint.toString());
  } catch (IOException e) {
   throw new RuntimeException(e);
  }
 }
}

@Override
public synchronized JournalOutputStream getCheckpointOutputStream(long latestSequenceNumber)
  throws IOException {
 if (mCheckpointOutputStream == null) {
  mCheckpointManager.recover();
  LOG.info("Creating tmp checkpoint file: {}", mTempCheckpoint);
  if (!mUfs.isDirectory(mJournal.getLocation().toString())) {
   LOG.info("Creating journal folder: {}", mJournal.getLocation());
   mUfs.mkdirs(mJournal.getLocation().toString());
  }
  mNextEntrySequenceNumber = latestSequenceNumber + 1;
  LOG.info("Latest journal sequence number: {} Next journal sequence number: {}",
    latestSequenceNumber, mNextEntrySequenceNumber);
  UnderFileSystemUtils.deleteFileIfExists(mUfs, mTempCheckpoint.toString());
  mCheckpointOutputStream = new CheckpointOutputStream(
    new DataOutputStream(mUfs.create(mTempCheckpoint.toString())));
 }
 return mCheckpointOutputStream;
}

UnderFileSystemUtils.deleteFileIfExists(mUfs, mCheckpoint.toString());
mUfs.renameFile(mTempBackupCheckpoint.toString(), mCheckpoint.toString());