FileSystem (Hadoop 1.2.1 API)
Date: 2013-07-22

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## org.apache.hadoop.fs
Class FileSystem

    java.lang.Object
      org.apache.hadoop.conf.Configured
          org.apache.hadoop.fs.FileSystem

All Implemented Interfaces:
  Closeable, Configurable

Direct Known Subclasses:
  FilterFileSystem, FTPFileSystem, KosmosFileSystem, NativeS3FileSystem, RawLocalFileSystem, S3FileSystem

    public abstract class FileSystem

extends Configured
implements Closeable

An abstract base class for a fairly generic filesystem. It may be implemented as a distributed filesystem, or as a "local" one that reflects the locally-connected disk. The local version exists for small Hadoop instances and for testing.

All user code that may potentially use the Hadoop Distributed File System should be written to use a FileSystem object. The Hadoop DFS is a multi-machine system that appears as a single disk. It's useful because of its fault tolerance and potentially very large capacity.

The local implementation is `LocalFileSystem` and distributed implementation is DistributedFileSystem.

Nested Class Summary
`static class` | `FileSystem.Statistics`

Field Summary
`static String` | `FS_DEFAULT_NAME_KEY`
`static org.apache.commons.logging.Log` | `LOG`
`protected FileSystem.Statistics` | `statistics` The statistics for this file system.

Constructor Summary
`protected` | `FileSystem()`

Method Summary
`static void` | `addFileSystemForTesting(URI uri, Configuration conf, FileSystem fs)` This method adds a file system for testing so that we can find it later.
`FSDataOutputStream` | `append(Path f)` Append to an existing file (optional operation).
`FSDataOutputStream` | `append(Path f, int bufferSize)` Append to an existing file (optional operation).
`abstract FSDataOutputStream` | `append(Path f, int bufferSize, Progressable progress)` Append to an existing file (optional operation).
`protected void` | `checkPath(Path path)` Check that a Path belongs to this FileSystem.
`static void` | `clearStatistics()`
`void` | `close()` No more filesystem operations are needed.
`static void` | `closeAll()` Close all cached filesystems.
`static void` | `closeAllForUGI(UserGroupInformation ugi)` Close all cached filesystems for a given UGI.
`void` | `completeLocalOutput(Path fsOutputFile, Path tmpLocalFile)` Called when we're all done writing to the target.
`void` | `concat(Path trg, Path[] srcs)` Concat existing files together.
`void` | `copyFromLocalFile(boolean delSrc, boolean overwrite, Path[] srcs, Path dst)` The src files are on the local disk.
`void` | `copyFromLocalFile(boolean delSrc, boolean overwrite, Path src, Path dst)` The src file is on the local disk.
`void` | `copyFromLocalFile(boolean delSrc, Path src, Path dst)` The src file is on the local disk.
`void` | `copyFromLocalFile(Path src, Path dst)` The src file is on the local disk.
`void` | `copyToLocalFile(boolean delSrc, Path src, Path dst)` The src file is under FS, and the dst is on the local disk.
`void` | `copyToLocalFile(Path src, Path dst)` The src file is under FS, and the dst is on the local disk.
`static FSDataOutputStream` | `create(FileSystem fs, Path file, FsPermission permission)` create a file with the provided permission The permission of the file is set to be the provided permission as in setPermission, not permission&~umask It is implemented using two RPCs.
`FSDataOutputStream` | `create(Path f)` Opens an FSDataOutputStream at the indicated Path.
`FSDataOutputStream` | `create(Path f, boolean overwrite)` Opens an FSDataOutputStream at the indicated Path.
`FSDataOutputStream` | `create(Path f, boolean overwrite, int bufferSize)` Opens an FSDataOutputStream at the indicated Path.
`FSDataOutputStream` | `create(Path f, boolean overwrite, int bufferSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream` | `create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize)` Opens an FSDataOutputStream at the indicated Path.
`FSDataOutputStream` | `create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`abstract FSDataOutputStream` | `create(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream` | `create(Path f, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream` | `create(Path f, short replication)` Opens an FSDataOutputStream at the indicated Path.
`FSDataOutputStream` | `create(Path f, short replication, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`boolean` | `createNewFile(Path f)` Creates the given Path as a brand-new zero-length file.
`FSDataOutputStream` | `createNonRecursive(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Deprecated. API only for 0.20-append
`FSDataOutputStream` | `createNonRecursive(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Deprecated. API only for 0.20-append
`abstract boolean` | `delete(Path f)` Deprecated. Use delete(Path, boolean) instead
`abstract boolean` | `delete(Path f, boolean recursive)` Delete a file.
`boolean` | `deleteOnExit(Path f)` Mark a path to be deleted when FileSystem is closed.
`boolean` | `exists(Path f)` Check if exists.
`static FileSystem` | `get(Configuration conf)` Returns the configured filesystem implementation.
`static FileSystem` | `get(URI uri, Configuration conf)` Returns the FileSystem for this URI's scheme and authority.
`static FileSystem` | `get(URI uri, Configuration conf, String user)`
`static List<FileSystem.Statistics>` | `getAllStatistics()` Return the FileSystem classes that have Statistics
`long` | `getBlockSize(Path f)` Deprecated. Use getFileStatus() instead
`static int` | `getCacheSize()` Get the number of entries in the filesystem cache
`String` | `getCanonicalServiceName()` Get a canonical service name for this file system.
`protected URI` | `getCanonicalUri()` Resolve the uri's hostname and add the default port if not in the uri
`ContentSummary` | `getContentSummary(Path f)` Return the `ContentSummary` of a given `Path`.
`long` | `getDefaultBlockSize()` Deprecated. use `getDefaultBlockSize(Path)` instead
`long` | `getDefaultBlockSize(Path f)` Return the number of bytes that large input files should be optimally be split into to minimize i/o time.
`protected int` | `getDefaultPort()` Get the default port for this file system.
`short` | `getDefaultReplication()` Deprecated. use `getDefaultReplication(Path)` instead
`short` | `getDefaultReplication(Path path)` Get the default replication.
`static URI` | `getDefaultUri(Configuration conf)` Get the default filesystem URI from a configuration.
`Token<?>` | `getDelegationToken(String renewer)` Get a new delegation token for this file system.
`BlockLocation[]` | `getFileBlockLocations(FileStatus file, long start, long len)` Return an array containing hostnames, offset and size of portions of the given file.
`FileChecksum` | `getFileChecksum(Path f)` Get the checksum of a file.
`abstract FileStatus` | `getFileStatus(Path f)` Return a file status object that represents the path.
`Path` | `getHomeDirectory()` Return the current user's home directory in this filesystem.
`long` | `getLength(Path f)` Deprecated. Use getFileStatus() instead
`static LocalFileSystem` | `getLocal(Configuration conf)` Get the local file syste
`String` | `getName()` Deprecated. call #getUri() instead.
`static FileSystem` | `getNamed(String name, Configuration conf)` Deprecated. call #get(URI,Configuration) instead.
`short` | `getReplication(Path src)` Deprecated. Use getFileStatus() instead
`static Map<String,FileSystem.Statistics>` | `getStatistics()` Deprecated. use `getAllStatistics()` instead
`static FileSystem.Statistics` | `getStatistics(String scheme, Class<? extends FileSystem> cls)` Get the statistics for a particular file system
`abstract URI` | `getUri()` Returns a URI whose scheme and authority identify this FileSystem.
`long` | `getUsed()` Return the total size of all files in the filesystem.
`abstract Path` | `getWorkingDirectory()` Get the current working directory for the given file system
`FileStatus[]` | `globStatus(Path pathPattern)` Return all the files that match filePattern and are not checksum files.
`FileStatus[]` | `globStatus(Path pathPattern, PathFilter filter)` Return an array of FileStatus objects whose path names match pathPattern and is accepted by the user-supplied path filter.
`void` | `initialize(URI name, Configuration conf)` Called after a new FileSystem instance is constructed.
`boolean` | `isDirectory(Path f)` Deprecated. Use getFileStatus() instead
`boolean` | `isFile(Path f)` True iff the named path is a regular file.
`abstract FileStatus[]` | `listStatus(Path f)` List the statuses of the files/directories in the given path if the path is a directory.
`FileStatus[]` | `listStatus(Path[] files)` Filter files/directories in the given list of paths using default path filter.
`FileStatus[]` | `listStatus(Path[] files, PathFilter filter)` Filter files/directories in the given list of paths using user-supplied path filter.
`FileStatus[]` | `listStatus(Path f, PathFilter filter)` Filter files/directories in the given path using the user-supplied path filter.
`Path` | `makeQualified(Path path)` Make sure that a path specifies a FileSystem.
`static boolean` | `mkdirs(FileSystem fs, Path dir, FsPermission permission)` create a directory with the provided permission The permission of the directory is set to be the provided permission as in setPermission, not permission&~umask
`boolean` | `mkdirs(Path f)` Call `mkdirs(Path, FsPermission)` with default permission.
`abstract boolean` | `mkdirs(Path f, FsPermission permission)` Make the given file and all non-existent parents into directories.
`void` | `moveFromLocalFile(Path[] srcs, Path dst)` The src files is on the local disk.
`void` | `moveFromLocalFile(Path src, Path dst)` The src file is on the local disk.
`void` | `moveToLocalFile(Path src, Path dst)` The src file is under FS, and the dst is on the local disk.
`FSDataInputStream` | `open(Path f)` Opens an FSDataInputStream at the indicated Path.
`abstract FSDataInputStream` | `open(Path f, int bufferSize)` Opens an FSDataInputStream at the indicated Path.
`static void` | `printStatistics()`
`protected void` | `processDeleteOnExit()` Delete all files that were marked as delete-on-exit.
`abstract boolean` | `rename(Path src, Path dst)` Renames Path src to Path dst.
`static void` | `setDefaultUri(Configuration conf, String uri)` Set the default filesystem URI in a configuration.
`static void` | `setDefaultUri(Configuration conf, URI uri)` Set the default filesystem URI in a configuration.
`void` | `setOwner(Path p, String username, String groupname)` Set owner of a path (i.e.
`void` | `setPermission(Path p, FsPermission permission)` Set permission of a path.
`boolean` | `setReplication(Path src, short replication)` Set replication for an existing file.
`void` | `setTimes(Path p, long mtime, long atime)` Set access time of a file
`void` | `setVerifyChecksum(boolean verifyChecksum)` Set the verify checksum flag.
`abstract void` | `setWorkingDirectory(Path new_dir)` Set the current working directory for the given file system.
`Path` | `startLocalOutput(Path fsOutputFile, Path tmpLocalFile)` Returns a local File that the user can write output to.

Methods inherited from class org.apache.hadoop.conf.Configured
`getConf, setConf`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### FS_DEFAULT_NAME_KEY

    public static final String FS_DEFAULT_NAME_KEY

See Also:
  Constant Field Values

### LOG

    public static final org.apache.commons.logging.Log LOG

### statistics

    protected FileSystem.Statistics statistics

  The statistics for this file system.

Constructor Detail

### FileSystem

    protected FileSystem()

Method Detail

### addFileSystemForTesting

    public static void addFileSystemForTesting(URI uri,
                                               Configuration conf,
                                               FileSystem fs)
                                        throws IOException

  This method adds a file system for testing so that we can find it later. It is only for testing.

  Parameters:
    `uri` - the uri to store it under
    `conf` - the configuration to store it under
    `fs` - the file system to store
  Throws:
    `IOException`

### get

    public static FileSystem get(URI uri,
                                 Configuration conf,
                                 String user)
                          throws IOException,
                                 InterruptedException

  Throws:
    `IOException`
    `InterruptedException`

### get

    public static FileSystem get(Configuration conf)
                          throws IOException

  Returns the configured filesystem implementation.

  Throws:
    `IOException`

### getDefaultUri

    public static URI getDefaultUri(Configuration conf)

  Get the default filesystem URI from a configuration.

  Parameters:
    `conf` - the configuration to access
  Returns:
    the uri of the default filesystem

### setDefaultUri

    public static void setDefaultUri(Configuration conf,
                                     URI uri)

  Set the default filesystem URI in a configuration.

  Parameters:
    `conf` - the configuration to alter
    `uri` - the new default filesystem uri

### setDefaultUri

    public static void setDefaultUri(Configuration conf,
                                     String uri)

  Set the default filesystem URI in a configuration.

  Parameters:
    `conf` - the configuration to alter
    `uri` - the new default filesystem uri

### getCacheSize

    @InterfaceAudience.Private
    public static int getCacheSize()

  Get the number of entries in the filesystem cache

  Returns:
    the number of entries in the filesystem cache

### initialize

    public void initialize(URI name,
                           Configuration conf)
                    throws IOException

  Called after a new FileSystem instance is constructed.

  Parameters:
    `name` - a uri whose authority section names the host, port, etc. for this FileSystem
    `conf` - the configuration
  Throws:
    `IOException`

### getUri

    public abstract URI getUri()

  Returns a URI whose scheme and authority identify this FileSystem.

### getCanonicalUri

    protected URI getCanonicalUri()

  Resolve the uri's hostname and add the default port if not in the uri

  Returns:
    URI
  See Also:
    `NetUtils.getCanonicalUri(URI, int)`

### getDefaultPort

    protected int getDefaultPort()

  Get the default port for this file system.

  Returns:
    the default port or 0 if there isn't one

### getCanonicalServiceName

    public String getCanonicalServiceName()

  Get a canonical service name for this file system. The token cache is the only user of this value, and uses it to lookup this filesystem's service tokens. The token cache will not attempt to acquire tokens if the service is null.

  Returns:
    a service string that uniquely identifies this file system, null if the filesystem does not implement tokens
  See Also:
    `SecurityUtil.buildDTServiceName(URI, int)`

### getName

    public String getName()

  Deprecated. call #getUri() instead.

### getNamed

    public static FileSystem getNamed(String name,
                                      Configuration conf)
                               throws IOException

  Deprecated. call #get(URI,Configuration) instead.

  Throws:
    `IOException`

### getLocal

    public static LocalFileSystem getLocal(Configuration conf)
                                    throws IOException

  Get the local file syste

  Parameters:
    `conf` - the configuration to configure the file system with
  Returns:
    a LocalFileSystem
  Throws:
    `IOException`

### get

    public static FileSystem get(URI uri,
                                 Configuration conf)
                          throws IOException

  Returns the FileSystem for this URI's scheme and authority. The scheme of the URI determines a configuration property name, `fs.scheme.class` whose value names the FileSystem class. The entire URI is passed to the FileSystem instance's initialize method.

  Throws:
    `IOException`

### closeAll

    public static void closeAll()
                         throws IOException

  Close all cached filesystems. Be sure those filesystems are not used anymore.

  Throws:
    `IOException`

### closeAllForUGI

    public static void closeAllForUGI(UserGroupInformation ugi)
                               throws IOException

  Close all cached filesystems for a given UGI. Be sure those filesystems are not used anymore.

  Parameters:
    `ugi` -
  Throws:
    `IOException`

### makeQualified

    public Path makeQualified(Path path)

  Make sure that a path specifies a FileSystem.

### create

    public static FSDataOutputStream create(FileSystem fs,
                                            Path file,
                                            FsPermission permission)
                                     throws IOException

  create a file with the provided permission The permission of the file is set to be the provided permission as in setPermission, not permission&~umask It is implemented using two RPCs. It is understood that it is inefficient, but the implementation is thread-safe. The other option is to change the value of umask in configuration to be 0, but it is not thread-safe.

  Parameters:
    `fs` - file system handle
    `file` - the name of the file to be created
    `permission` - the permission of the file
  Returns:
    an output stream
  Throws:
    `IOException`

### mkdirs

    public static boolean mkdirs(FileSystem fs,
                                 Path dir,
                                 FsPermission permission)
                          throws IOException

  create a directory with the provided permission The permission of the directory is set to be the provided permission as in setPermission, not permission&~umask

  Parameters:
    `fs` - file system handle
    `dir` - the name of the directory to be created
    `permission` - the permission of the directory
  Returns:
    true if the directory creation succeeds; false otherwise
  Throws:
    `IOException`
  See Also:
    `create(FileSystem, Path, FsPermission)`

### checkPath

    protected void checkPath(Path path)

  Check that a Path belongs to this FileSystem.

### getFileBlockLocations

    public BlockLocation[] getFileBlockLocations(FileStatus file,
                                                 long start,
                                                 long len)
                                          throws IOException

  Return an array containing hostnames, offset and size of portions of the given file. For a nonexistent file or regions, null will be returned. This call is most helpful with DFS, where it returns hostnames of machines that contain the given file. The FileSystem will simply return an elt containing 'localhost'.

  Throws:
    `IOException`

### open

    public abstract FSDataInputStream open(Path f,
                                           int bufferSize)
                                    throws IOException

  Opens an FSDataInputStream at the indicated Path.

  Parameters:
    `f` - the file name to open
    `bufferSize` - the size of the buffer to be used.
  Throws:
    `IOException`

### open

    public FSDataInputStream open(Path f)
                           throws IOException

  Opens an FSDataInputStream at the indicated Path.

  Parameters:
    `f` - the file to open
  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path. Files are overwritten by default.

  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     boolean overwrite)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path.

  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     Progressable progress)
                              throws IOException

  Create an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.

  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     short replication)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path. Files are overwritten by default.

  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     short replication,
                                     Progressable progress)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.

  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     boolean overwrite,
                                     int bufferSize)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path.

  Parameters:
    `f` - the file name to open
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     boolean overwrite,
                                     int bufferSize,
                                     Progressable progress)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting.

  Parameters:
    `f` - the file name to open
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     boolean overwrite,
                                     int bufferSize,
                                     short replication,
                                     long blockSize)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path.

  Parameters:
    `f` - the file name to open
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
    `replication` - required block replication for the file.
  Throws:
    `IOException`

### create

    public FSDataOutputStream create(Path f,
                                     boolean overwrite,
                                     int bufferSize,
                                     short replication,
                                     long blockSize,
                                     Progressable progress)
                              throws IOException

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting.

  Parameters:
    `f` - the file name to open
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
    `replication` - required block replication for the file.
  Throws:
    `IOException`

### create

    public abstract FSDataOutputStream create(Path f,
                                              FsPermission permission,
                                              boolean overwrite,
                                              int bufferSize,
                                              short replication,
                                              long blockSize,
                                              Progressable progress)
                                       throws IOException

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting.

  Parameters:
    `f` - the file name to open
    `permission` -
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
    `replication` - required block replication for the file.
    `blockSize` -
    `progress` -
  Throws:
    `IOException`
  See Also:
    `setPermission(Path, FsPermission)`

### createNonRecursive

    @Deprecated
    public FSDataOutputStream createNonRecursive(Path f,
                                                            boolean overwrite,
                                                            int bufferSize,
                                                            short replication,
                                                            long blockSize,
                                                            Progressable progress)
                                          throws IOException

  Deprecated. API only for 0.20-append

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.

  Parameters:
    `f` - the file name to open
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
    `replication` - required block replication for the file.
    `blockSize` -
    `progress` -
  Throws:
    `IOException`
  See Also:
    `setPermission(Path, FsPermission)`

### createNonRecursive

    @Deprecated
    public FSDataOutputStream createNonRecursive(Path f,
                                                            FsPermission permission,
                                                            boolean overwrite,
                                                            int bufferSize,
                                                            short replication,
                                                            long blockSize,
                                                            Progressable progress)
                                          throws IOException

  Deprecated. API only for 0.20-append

  Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.

  Parameters:
    `f` - the file name to open
    `permission` -
    `overwrite` - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    `bufferSize` - the size of the buffer to be used.
    `replication` - required block replication for the file.
    `blockSize` -
    `progress` -
  Throws:
    `IOException`
  See Also:
    `setPermission(Path, FsPermission)`

### createNewFile

    public boolean createNewFile(Path f)
                          throws IOException

  Creates the given Path as a brand-new zero-length file. If create fails, or if it already existed, return false.

  Throws:
    `IOException`

### append

    public FSDataOutputStream append(Path f)
                              throws IOException

  Append to an existing file (optional operation). Same as append(f, getConf().getInt("io.file.buffer.size", 4096), null)

  Parameters:
    `f` - the existing file to be appended.
  Throws:
    `IOException`

### append

    public FSDataOutputStream append(Path f,
                                     int bufferSize)
                              throws IOException

  Append to an existing file (optional operation). Same as append(f, bufferSize, null).

  Parameters:
    `f` - the existing file to be appended.
    `bufferSize` - the size of the buffer to be used.
  Throws:
    `IOException`

### append

    public abstract FSDataOutputStream append(Path f,
                                              int bufferSize,
                                              Progressable progress)
                                       throws IOException

  Append to an existing file (optional operation).

  Parameters:
    `f` - the existing file to be appended.
    `bufferSize` - the size of the buffer to be used.
    `progress` - for reporting progress if it is not null.
  Throws:
    `IOException`

### concat

    public void concat(Path trg,
                       Path[] srcs)
                throws IOException

  Concat existing files together.

  Parameters:
    `trg` - the path to the target destination.
    `psrcs` - the paths to the sources to use for the concatenation.
  Throws:
    `IOException`

### getReplication

    @Deprecated
    public short getReplication(Path src)
                         throws IOException

  Deprecated. Use getFileStatus() instead

  Get replication.

  Parameters:
    `src` - file name
  Returns:
    file replication
  Throws:
    `IOException`

### setReplication

    public boolean setReplication(Path src,
                                  short replication)
                           throws IOException

  Set replication for an existing file.

  Parameters:
    `src` - file name
    `replication` - new replication
  Returns:
    true if successful; false if file does not exist or is a directory
  Throws:
    `IOException`

### rename

    public abstract boolean rename(Path src,
                                   Path dst)
                            throws IOException

  Renames Path src to Path dst. Can take place on local fs or remote DFS.

  Throws:
    `IOException`

### delete

    @Deprecated
    public abstract boolean delete(Path f)
                            throws IOException

  Deprecated. Use delete(Path, boolean) instead

  Throws:
    `IOException`

### delete

    public abstract boolean delete(Path f,
                                   boolean recursive)
                            throws IOException

  Delete a file.

  Parameters:
    `f` - the path to delete.
    `recursive` - if path is a directory and set to true, the directory is deleted else throws an exception. In case of a file the recursive can be set to either true or false.
  Returns:
    true if delete is successful else false.
  Throws:
    `IOException`

### deleteOnExit

    public boolean deleteOnExit(Path f)
                         throws IOException

  Mark a path to be deleted when FileSystem is closed. When the JVM shuts down, all FileSystem objects will be closed automatically. Then, the marked path will be deleted as a result of closing the FileSystem. The path has to exist in the file system.

  Parameters:
    `f` - the path to delete.
  Returns:
    true if deleteOnExit is successful, otherwise false.
  Throws:
    `IOException`

### processDeleteOnExit

    protected void processDeleteOnExit()

  Delete all files that were marked as delete-on-exit. This recursively deletes all files in the specified paths.

### exists

    public boolean exists(Path f)
                   throws IOException

  Check if exists.

  Parameters:
    `f` - source file
  Throws:
    `IOException`

### isDirectory

    @Deprecated
    public boolean isDirectory(Path f)
                        throws IOException

  Deprecated. Use getFileStatus() instead

  Throws:
    `IOException`

### isFile

    public boolean isFile(Path f)
                   throws IOException

  True iff the named path is a regular file.

  Throws:
    `IOException`

### getLength

    @Deprecated
    public long getLength(Path f)
                   throws IOException

  Deprecated. Use getFileStatus() instead

  Throws:
    `IOException`

### getContentSummary

    public ContentSummary getContentSummary(Path f)
                                     throws IOException

  Return the `ContentSummary` of a given `Path`.

  Throws:
    `IOException`

### listStatus

    public abstract FileStatus[] listStatus(Path f)
                                     throws IOException

  List the statuses of the files/directories in the given path if the path is a directory.

  Parameters:
    `f` - given path
  Returns:
    the statuses of the files/directories in the given patch returns null, if Path f does not exist in the FileSystem
  Throws:
    `IOException`

### listStatus

    public FileStatus[] listStatus(Path f,
                                   PathFilter filter)
                            throws IOException

  Filter files/directories in the given path using the user-supplied path filter.

  Parameters:
    `f` - a path name
    `filter` - the user-supplied path filter
  Returns:
    an array of FileStatus objects for the files under the given path after applying the filter
  Throws:
    `IOException` - if encounter any problem while fetching the status

### listStatus

    public FileStatus[] listStatus(Path[] files)
                            throws IOException

  Filter files/directories in the given list of paths using default path filter.

  Parameters:
    `files` - a list of paths
  Returns:
    a list of statuses for the files under the given paths after applying the filter default Path filter
  Throws:
    `IOException`

### listStatus

    public FileStatus[] listStatus(Path[] files,
                                   PathFilter filter)
                            throws IOException

  Filter files/directories in the given list of paths using user-supplied path filter.

  Parameters:
    `files` - a list of paths
    `filter` - the user-supplied path filter
  Returns:
    a list of statuses for the files under the given paths after applying the filter
  Throws:
    `IOException`

### globStatus

    public FileStatus[] globStatus(Path pathPattern)
                            throws IOException

  Return all the files that match filePattern and are not checksum files. Results are sorted by their names.

  A filename pattern is composed of regular characters and special pattern matching characters, which are:

    `?`
      Matches any single character.

    `*`
      Matches zero or more characters.

    `[abc]`
      Matches a single character from character set `{a,b,c}`.

    `[a-b]`
      Matches a single character from the character range `{a...b}`. Note that character `a` must be lexicographically less than or equal to character `b`.

    `[^a]`
      Matches a single character that is not from character set or range `{a}`. Note that the `^` character must occur immediately to the right of the opening bracket.

    `\c`
      Removes (escapes) any special meaning of character c.

    `{ab,cd}`
      Matches a string from the string set `{ab, cd}`

    `{ab,c{de,fh}}`
      Matches a string from the string set `{ab, cde, cfh}`

  Parameters:
    `pathPattern` - a regular expression specifying a pth pattern
  Returns:
    an array of paths that match the path pattern
  Throws:
    `IOException`

### globStatus

    public FileStatus[] globStatus(Path pathPattern,
                                   PathFilter filter)
                            throws IOException

  Return an array of FileStatus objects whose path names match pathPattern and is accepted by the user-supplied path filter. Results are sorted by their path names. Return null if pathPattern has no glob and the path does not exist. Return an empty array if pathPattern has a glob and no path matches it.

  Parameters:
    `pathPattern` - a regular expression specifying the path pattern
    `filter` - a user-supplied path filter
  Returns:
    an array of FileStatus objects
  Throws:
    `IOException` - if any I/O error occurs when fetching file status

### getHomeDirectory

    public Path getHomeDirectory()

  Return the current user's home directory in this filesystem. The default implementation returns "/user/$USER/".

### getDelegationToken

    public Token<?> getDelegationToken(String renewer)
                                throws IOException

  Get a new delegation token for this file system.

  Parameters:
    `renewer` - the account name that is allowed to renew the token.
  Returns:
    a new delegation token
  Throws:
    `IOException`

### setWorkingDirectory

    public abstract void setWorkingDirectory(Path new_dir)

  Set the current working directory for the given file system. All relative paths will be resolved relative to it.

  Parameters:
    `new_dir` -

### getWorkingDirectory

    public abstract Path getWorkingDirectory()

  Get the current working directory for the given file system

  Returns:
    the directory pathname

### mkdirs

    public boolean mkdirs(Path f)
                   throws IOException

  Call `mkdirs(Path, FsPermission)` with default permission.

  Throws:
    `IOException`

### mkdirs

    public abstract boolean mkdirs(Path f,
                                   FsPermission permission)
                            throws IOException

  Make the given file and all non-existent parents into directories. Has the semantics of Unix 'mkdir -p'. Existence of the directory hierarchy is not an error.

  Throws:
    `IOException`

### copyFromLocalFile

    public void copyFromLocalFile(Path src,
                                  Path dst)
                           throws IOException

  The src file is on the local disk. Add it to FS at the given dst name and the source is kept intact afterwards

  Throws:
    `IOException`

### moveFromLocalFile

    public void moveFromLocalFile(Path[] srcs,
                                  Path dst)
                           throws IOException

  The src files is on the local disk. Add it to FS at the given dst name, removing the source afterwards.

  Throws:
    `IOException`

### moveFromLocalFile

    public void moveFromLocalFile(Path src,
                                  Path dst)
                           throws IOException

  The src file is on the local disk. Add it to FS at the given dst name, removing the source afterwards.

  Throws:
    `IOException`

### copyFromLocalFile

    public void copyFromLocalFile(boolean delSrc,
                                  Path src,
                                  Path dst)
                           throws IOException

  The src file is on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed

  Throws:
    `IOException`

### copyFromLocalFile

    public void copyFromLocalFile(boolean delSrc,
                                  boolean overwrite,
                                  Path[] srcs,
                                  Path dst)
                           throws IOException

  The src files are on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed

  Throws:
    `IOException`

### copyFromLocalFile

    public void copyFromLocalFile(boolean delSrc,
                                  boolean overwrite,
                                  Path src,
                                  Path dst)
                           throws IOException

  The src file is on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed

  Throws:
    `IOException`

### copyToLocalFile

    public void copyToLocalFile(Path src,
                                Path dst)
                         throws IOException

  The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name.

  Throws:
    `IOException`

### moveToLocalFile

    public void moveToLocalFile(Path src,
                                Path dst)
                         throws IOException

  The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name. Remove the source afterwards

  Throws:
    `IOException`

### copyToLocalFile

    public void copyToLocalFile(boolean delSrc,
                                Path src,
                                Path dst)
                         throws IOException

  The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name. delSrc indicates if the src will be removed or not.

  Throws:
    `IOException`

### startLocalOutput

    public Path startLocalOutput(Path fsOutputFile,
                                 Path tmpLocalFile)
                          throws IOException

  Returns a local File that the user can write output to. The caller provides both the eventual FS target name and the local working file. If the FS is local, we write directly into the target. If the FS is remote, we write into the tmp local area.

  Throws:
    `IOException`

### completeLocalOutput

    public void completeLocalOutput(Path fsOutputFile,
                                    Path tmpLocalFile)
                             throws IOException

  Called when we're all done writing to the target. A local FS will do nothing, because we've written to exactly the right place. A remote FS will copy the contents of tmpLocalFile to the correct target at fsOutputFile.

  Throws:
    `IOException`

### close

    public void close()
               throws IOException

  No more filesystem operations are needed. Will release any held locks.

  Specified by:
    `close` in interface `Closeable`
  Throws:
    `IOException`

### getUsed

    public long getUsed()
                 throws IOException

  Return the total size of all files in the filesystem.

  Throws:
    `IOException`

### getBlockSize

    @Deprecated
    public long getBlockSize(Path f)
                      throws IOException

  Deprecated. Use getFileStatus() instead

  Throws:
    `IOException`

### getDefaultBlockSize

    @Deprecated
    public long getDefaultBlockSize()

  Deprecated. use `getDefaultBlockSize(Path)` instead

  Return the number of bytes that large input files should be optimally be split into to minimize i/o time.

### getDefaultBlockSize

    public long getDefaultBlockSize(Path f)

  Return the number of bytes that large input files should be optimally be split into to minimize i/o time.

  Parameters:
    `f` - path of file
  Returns:
    the default block size for the path's filesystem

### getDefaultReplication

    @Deprecated
    public short getDefaultReplication()

  Deprecated. use `getDefaultReplication(Path)` instead

  Get the default replication.

### getDefaultReplication

    public short getDefaultReplication(Path path)

  Get the default replication.

  Parameters:
    `path` - of the file
  Returns:
    default replication for the path's filesystem

### getFileStatus

    public abstract FileStatus getFileStatus(Path f)
                                      throws IOException

  Return a file status object that represents the path.

  Parameters:
    `f` - The path we want information from
  Returns:
    a FileStatus object
  Throws:
    `FileNotFoundException` - when the path does not exist; IOException see specific implementation
    `IOException`

### getFileChecksum

    public FileChecksum getFileChecksum(Path f)
                                 throws IOException

  Get the checksum of a file.

  Parameters:
    `f` - The file path
  Returns:
    The file checksum. The default return value is null, which indicates that no checksum algorithm is implemented in the corresponding FileSystem.
  Throws:
    `IOException`

### setVerifyChecksum

    public void setVerifyChecksum(boolean verifyChecksum)

  Set the verify checksum flag. This is only applicable if the corresponding FileSystem supports checksum. By default doesn't do anything.

  Parameters:
    `verifyChecksum` -

### setPermission

    public void setPermission(Path p,
                              FsPermission permission)
                       throws IOException

  Set permission of a path.

  Parameters:
    `p` -
    `permission` -
  Throws:
    `IOException`

### setOwner

    public void setOwner(Path p,
                         String username,
                         String groupname)
                  throws IOException

  Set owner of a path (i.e. a file or a directory). The parameters username and groupname cannot both be null.

  Parameters:
    `p` - The path
    `username` - If it is null, the original username remains unchanged.
    `groupname` - If it is null, the original groupname remains unchanged.
  Throws:
    `IOException`

### setTimes

    public void setTimes(Path p,
                         long mtime,
                         long atime)
                  throws IOException

  Set access time of a file

  Parameters:
    `p` - The path
    `mtime` - Set the modification time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set modification time.
    `atime` - Set the access time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set access time.
  Throws:
    `IOException`

### getStatistics

    public static Map<String,FileSystem.Statistics> getStatistics()

  Deprecated. use `getAllStatistics()` instead

  Get the Map of Statistics object indexed by URI Scheme.

  Returns:
    a Map having a key as URI scheme and value as Statistics object

### getAllStatistics

    public static List<FileSystem.Statistics> getAllStatistics()

  Return the FileSystem classes that have Statistics

### getStatistics

    public static FileSystem.Statistics getStatistics(String scheme,
                                                      Class<? extends FileSystem> cls)

  Get the statistics for a particular file system

  Parameters:
    `cls` - the class to lookup
  Returns:
    a statistics object

### clearStatistics

    public static void clearStatistics()

### printStatistics

    public static void printStatistics()
                                throws IOException

  Throws:
    `IOException`

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