org.apache.hadoop.fs.Path#isRoot ( )源码实例Demo

/**
 * Deletes the children of the input dir path by iterating though the
 * DeleteIterator.
 *
 * @param f directory path to be deleted
 * @return true if successfully deletes all required keys, false otherwise
 * @throws IOException
 */
private boolean innerDelete(Path f, boolean recursive) throws IOException {
  LOG.trace("delete() path:{} recursive:{}", f, recursive);
  try {
    DeleteIterator iterator = new DeleteIterator(f, recursive);

    if (f.isRoot()) {
      LOG.warn("Cannot delete root directory.");
      return false;
    }

    return iterator.iterate();
  } catch (FileNotFoundException e) {
    if (LOG.isDebugEnabled()) {
      LOG.debug("Couldn't delete {} - does not exist", f);
    }
    return false;
  }
}
 

@Override
public FSDataInputStream open(Path f, int bufferSize) throws IOException {
  Path absolutePath = toAbsolutePath(f);
  checkPath(absolutePath);

  // Handle root
  if (absolutePath.isRoot()) {
    throw new AccessControlException("Cannot open " + f);
  }

  try {
    RemotePath remotePath = getRemotePath(absolutePath);

    FileSystem delegate = getDelegateFileSystem(remotePath.address);
    return delegate.open(remotePath.path, bufferSize);
  } catch (IllegalArgumentException e) {
    throw (FileNotFoundException) (new FileNotFoundException("No file " + absolutePath).initCause(e));
  }
}
 

@Override
public boolean delete(Path f, boolean recursive) throws IOException {
  Path absolutePath = toAbsolutePath(f);
  checkPath(absolutePath);

  // Handle root
  if (absolutePath.isRoot()) {
    throw new AccessControlException("Cannot delete " + f);
  }

  if (!isRemoteFile(f)) {
    // In our remote view, there might be a directory, so delete task should handle this case
    return new DeleteTask(absolutePath, recursive).get();
  }

  try {
    RemotePath remotePath = getRemotePath(absolutePath);

    FileSystem delegate = getDelegateFileSystem(remotePath.address);
    return delegate.delete(remotePath.path, recursive);
  } catch (IllegalArgumentException e) {
    throw (FileNotFoundException) (new FileNotFoundException("No file " + absolutePath).initCause(e));
  }
}
 

@Override
public boolean mkdirs(Path f, FsPermission permission) throws IOException {
  Path absolutePath = toAbsolutePath(f);
  checkPath(absolutePath);

  // Handle root
  if (absolutePath.isRoot()) {
    // Path always exists
    return true;
  }

  if (isRemoteFile(absolutePath)) {
    // Attempting to create a subdirectory for a file
    throw new IOException("Cannot create a directory under file " + f);
  }

  return new MkdirsTask(absolutePath, permission).get();
}
 

/**
 * Create the output folder and optionally set ownership.
 */
private void createOutputPath(final Path path) throws IOException {
  if (filesUser == null && filesGroup == null) {
    outputFs.mkdirs(path);
  } else {
    Path parent = path.getParent();
    if (!outputFs.exists(parent) && !parent.isRoot()) {
      createOutputPath(parent);
    }
    outputFs.mkdirs(path);
    if (filesUser != null || filesGroup != null) {
      // override the owner when non-null user/group is specified
      outputFs.setOwner(path, filesUser, filesGroup);
    }
    if (filesMode > 0) {
      outputFs.setPermission(path, new FsPermission(filesMode));
    }
  }
}
 

private static boolean isChildDirectory(Path parentDirectory, Path childDirectory)
{
    if (parentDirectory.equals(childDirectory)) {
        return true;
    }
    if (childDirectory.isRoot()) {
        return false;
    }
    return isChildDirectory(parentDirectory, childDirectory.getParent());
}
 

private void deleteUnnecessaryFakeDirectories(Path f) throws IOException {
  while (true) {
    try {
      String key = pathToKey(f);
      if (key.isEmpty()) {
        break;
      }

      S3AFileStatus status = getFileStatus(f);

      if (status.isDirectory() && status.isEmptyDirectory()) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Deleting fake directory " + key + "/");
        }
        s3.deleteObject(bucket, key + "/");
        statistics.incrementWriteOps(1);
      }
    } catch (FileNotFoundException | AmazonServiceException e) {
    }

    if (f.isRoot()) {
      break;
    }

    f = f.getParent();
  }
}
 

/**
 * Block any operation on the root path. This is a safety check
 * @param path path in the filesystem
 * @param allowRootOperation can the root directory be manipulated?
 * @throws IOException if the operation was rejected
 */
public static void rejectRootOperation(Path path,
    boolean allowRootOperation) throws IOException {
  if (path.isRoot() && !allowRootOperation) {
    throw new IOException("Root directory operation rejected: " + path);
  }
}
 

@Override
public FileStatus getFileStatus(Path f) throws IOException {
  if (f.isRoot()) {
    return new FileStatus(0, true, 0, 0, 0, f);
  }
  return null;
}
 

public static Path getRoot(Path path) {
  Path current = path;
  while (!current.isRoot()) {
    current = current.getParent();
  }
  return current;
}
 

/**
 * Create a new file. Three possibilities:
 *  - This is a data node and you're trying to create a unqualified file => write locally.
 *  - This is a client node and you're trying to create unqualified file => pick a random data node and write there.
 *  - The path you provide is qualified => write to that node.
 */
@Override
public FSDataOutputStream create(Path f, FsPermission permission, boolean overwrite, int bufferSize,
    short replication, long blockSize, Progressable progress) throws IOException {
  final Path absolutePath = toAbsolutePath(f);
  checkPath(absolutePath);

  // Handle root
  if (absolutePath.isRoot()) {
    throw new AccessControlException("Cannot create " + f);
  }

  if(!isRemoteFile(f)){
    if (isDirectory(absolutePath)) {
      throw new FileAlreadyExistsException("Directory already exists: " + f);
    }

    // Only canonicalized path/remote files are allowed
    throw new IOException("Cannot create non-canonical path " + f);
  }

  try {
    RemotePath remotePath = getRemotePath(absolutePath);
    return getDelegateFileSystem(remotePath.address).create(remotePath.path, permission, overwrite, bufferSize, replication, blockSize, progress);
  } catch (IllegalArgumentException e) {
    throw (IOException) (new IOException("Cannot create file " + absolutePath).initCause(e));
  }
}
 

/**
 * Create a new file. Three possibilities:
 *  - This is a data node and you're trying to append a unqualified file => write locally.
 *  - The path you provide is qualified => write to that node.
 *
 *  If this is a client node and you try to write to a unqualified file, we'll throw
 */
@Override
public FSDataOutputStream append(Path f, int bufferSize, Progressable progress) throws IOException {
  Path absolutePath = toAbsolutePath(f);
  checkPath(absolutePath);

  // Handle root
  if (absolutePath.isRoot()) {
    throw new AccessControlException("Cannot open " + f);
  }

  if(!isRemoteFile(f)){
    if (isDirectory(absolutePath)) {
      throw new FileAlreadyExistsException("Directory already exists: " + f);
    }

    // Only fully canonicalized/remote files are allowed
    throw new IOException("Cannot create non-canonical path " + f);
  }

  try {
    RemotePath remotePath = getRemotePath(absolutePath);

    FileSystem delegate = getDelegateFileSystem(remotePath.address);
    return delegate.append(remotePath.path, bufferSize, progress);
  } catch (IllegalArgumentException e) {
    throw (FileNotFoundException) (new FileNotFoundException("No file " + absolutePath).initCause(e));
  }
}
 

private void deleteUnnecessaryFakeDirectories(Path f) throws IOException {
  while (true) {
    try {
      String key = pathToKey(f);
      if (key.isEmpty()) {
        break;
      }

      S3AFileStatus status = getFileStatus(f);

      if (status.isDirectory() && status.isEmptyDirectory()) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Deleting fake directory " + key + "/");
        }
        s3.deleteObject(bucket, key + "/");
        statistics.incrementWriteOps(1);
      }
    } catch (FileNotFoundException | AmazonServiceException e) {
    }

    if (f.isRoot()) {
      break;
    }

    f = f.getParent();
  }
}
 

/**
 * Block any operation on the root path. This is a safety check
 * @param path path in the filesystem
 * @param allowRootOperation can the root directory be manipulated?
 * @throws IOException if the operation was rejected
 */
public static void rejectRootOperation(Path path,
    boolean allowRootOperation) throws IOException {
  if (path.isRoot() && !allowRootOperation) {
    throw new IOException("Root directory operation rejected: " + path);
  }
}
 

@Override
public FileStatus getFileStatus(Path f) throws IOException {
  if (f.isRoot()) {
    return new FileStatus(0, true, 0, 0, 0, f);
  }
  return null;
}
 

/**
 * org.apache.hadoop.fs.Path assumes that there separator in file system naming and "/" is the separator.
 * When org.apache.hadoop.fs.Path sees "/" in path String, it splits into parent and name. As fileID is a random
 * String determined by Google and it can contain "/" itself, this method check if parent and name is separated and
 * restore "/" back to file ID.
 *
 * @param p
 * @return
 */
public static String toFileId(Path p) {
  if (p.isRoot()) {
    return "";
  }
  final String format = "%s" + Path.SEPARATOR + "%s";
  if (p.getParent() != null && StringUtils.isEmpty(p.getParent().getName())) {
    return p.getName();
  }
  return String.format(format, toFileId(p.getParent()), p.getName());
}
 

/**
 * Returns the root path for the specified path.
 *
 * @see Path
 */
public static Path getRootPath(Path path) {
  if (path.isRoot()) {
    return path;
  }
  return getRootPath(path.getParent());
}
 

/**
 * Validates a single whitelist path against the coprocessor path
 * @param  coprocPath the path to the coprocessor including scheme
 * @param  wlPath     can be:
 *                      1) a "*" to wildcard all coprocessor paths
 *                      2) a specific filesystem (e.g. hdfs://my-cluster/)
 *                      3) a wildcard path to be evaluated by
 *                         {@link FilenameUtils#wildcardMatch(String, String)}
 *                         path can specify scheme or not (e.g.
 *                         "file:///usr/hbase/coprocessors" or for all
 *                         filesystems "/usr/hbase/coprocessors")
 * @return             if the path was found under the wlPath
 */
private static boolean validatePath(Path coprocPath, Path wlPath) {
  // verify if all are allowed
  if (wlPath.toString().equals("*")) {
    return(true);
  }

  // verify we are on the same filesystem if wlPath has a scheme
  if (!wlPath.isAbsoluteAndSchemeAuthorityNull()) {
    String wlPathScheme = wlPath.toUri().getScheme();
    String coprocPathScheme = coprocPath.toUri().getScheme();
    String wlPathHost = wlPath.toUri().getHost();
    String coprocPathHost = coprocPath.toUri().getHost();
    if (wlPathScheme != null) {
      wlPathScheme = wlPathScheme.toString().toLowerCase();
    } else {
      wlPathScheme = "";
    }
    if (wlPathHost != null) {
      wlPathHost = wlPathHost.toString().toLowerCase();
    } else {
      wlPathHost = "";
    }
    if (coprocPathScheme != null) {
      coprocPathScheme = coprocPathScheme.toString().toLowerCase();
    } else {
      coprocPathScheme = "";
    }
    if (coprocPathHost != null) {
      coprocPathHost = coprocPathHost.toString().toLowerCase();
    } else {
      coprocPathHost = "";
    }
    if (!wlPathScheme.equals(coprocPathScheme) || !wlPathHost.equals(coprocPathHost)) {
      return(false);
    }
  }

  // allow any on this file-system (file systems were verified to be the same above)
  if (wlPath.isRoot()) {
    return(true);
  }

  // allow "loose" matches stripping scheme
  if (FilenameUtils.wildcardMatch(
      Path.getPathWithoutSchemeAndAuthority(coprocPath).toString(),
      Path.getPathWithoutSchemeAndAuthority(wlPath).toString())) {
    return(true);
  }
  return(false);
}
 

/**
 * Create a fake parent directory key if it does not already exist and no
 * other child of this parent directory exists.
 *
 * @param f path to the fake parent directory
 * @throws IOException
 */
private void createFakeParentDirectory(Path f) throws IOException {
  Path parent = f.getParent();
  if (parent != null && !parent.isRoot()) {
    createFakeDirectoryIfNecessary(parent);
  }
}
 

/**
 * Create a fake parent directory key if it does not already exist and no
 * other child of this parent directory exists.
 *
 * @param f path to the fake parent directory
 * @throws IOException
 */
private void createFakeParentDirectory(Path f) throws IOException {
  Path parent = f.getParent();
  if (parent != null && !parent.isRoot()) {
    createFakeDirectoryIfNecessary(parent);
  }
}