org.apache.hadoop.fs
Class FilterFileSystem

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

All Implemented Interfaces:

Configurable

Direct Known Subclasses:

ChecksumFileSystem, PhasedFileSystem

public class FilterFileSystem
extends FileSystem

A FilterFileSystem contains some other file system, which it uses as its basic file system, possibly transforming the data along the way or providing additional functionality. The class FilterFileSystem itself simply overrides all methods of FileSystem with versions that pass all requests to the contained file system. Subclasses of FilterFileSystem may further override some of these methods and may also provide additional methods and fields.

Author:

Hairong Kuang

Field Summary

protected FileSystem

fs

Fields inherited from class org.apache.hadoop.fs.FileSystem

LOG

Constructor Summary

FilterFileSystem(FileSystem fs)

Method Summary

protected void	checkPath(Path path) Check that a Path belongs to this FileSystem.
void	close() No more filesystem operations are needed.
void	completeLocalOutput(Path fsOutputFile, Path tmpLocalFile) Called when we're all done writing to the target.
void	copyFromLocalFile(boolean delSrc, 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.
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.
boolean	delete(Path f) Delete a file
boolean	exists(Path f) Check if exists.
long	getBlockSize(Path f) Get the block size for a particular file.
Configuration	getConf() Return the configuration used by this object.
long	getDefaultBlockSize() Return the number of bytes that large input files should be optimally be split into to minimize i/o time.
short	getDefaultReplication() Get the default replication.
String[][]	getFileCacheHints(Path f, long start, long len) Return a 2D array of size 1x1 or greater, containing hostnames where portions of the given file can be found.
long	getLength(Path f) The number of bytes in a file.
String	getName() Deprecated. call #getUri() instead.
short	getReplication(Path src) Get replication.
URI	getUri() Returns a URI whose scheme and authority identify this FileSystem.
Path	getWorkingDirectory() Get the current working directory for the given file system
void	initialize(URI name, Configuration conf) Called after a new FileSystem instance is constructed.
boolean	isDirectory(Path f) True iff the named path is a directory.
Path[]	listPaths(Path f) List files in a directory.
void	lock(Path f, boolean shared) Deprecated. FS does not support file locks anymore.
Path	makeQualified(Path path) Make sure that a path specifies a FileSystem.
boolean	mkdirs(Path f) Make the given file and all non-existent parents into directories.
FSDataInputStream	open(Path f, int bufferSize) Opens an FSDataInputStream at the indicated Path.
void	release(Path f) Deprecated. FS does not support file locks anymore.
boolean	rename(Path src, Path dst) Renames Path src to Path dst.
boolean	setReplication(Path src, short replication) Set replication for an existing file.
void	setWorkingDirectory(Path newDir) 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.fs.FileSystem

closeAll, copyFromLocalFile, copyToLocalFile, create, create, create, create, create, create, create, createNewFile, get, get, getContentLength, getLocal, getNamed, getUsed, globPaths, globPaths, isFile, listPaths, listPaths, listPaths, moveFromLocalFile, moveToLocalFile, open, parseArgs

Methods inherited from class org.apache.hadoop.conf.Configured

setConf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

fs

protected FileSystem fs

Constructor Detail

FilterFileSystem

public FilterFileSystem(FileSystem fs)

Method Detail

initialize

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

Called after a new FileSystem instance is constructed.

Specified by:

initialize in class FileSystem

Parameters:

name - a uri whose authority section names the host, port, etc. for this FileSystem

conf - the configuration

Throws:

IOException

getUri

public URI getUri()

Returns a URI whose scheme and authority identify this FileSystem.

Specified by:

getUri in class FileSystem

getName

public String getName()

Deprecated. call #getUri() instead.

Specified by:

getName in class FileSystem

makeQualified

public Path makeQualified(Path path)

Make sure that a path specifies a FileSystem.

Overrides:

makeQualified in class FileSystem

checkPath

protected void checkPath(Path path)

Check that a Path belongs to this FileSystem.

Overrides:

checkPath in class FileSystem

getFileCacheHints

public String[][] getFileCacheHints(Path f,
                                    long start,
                                    long len)
                             throws IOException

Return a 2D array of size 1x1 or greater, containing hostnames where portions of the given file can be found. 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'.

Specified by:

getFileCacheHints in class FileSystem

Throws:

IOException

open

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

Opens an FSDataInputStream at the indicated Path.

Specified by:

open in class FileSystem

Parameters:

f - the file name to open

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,
                                 Progressable progress)
                          throws IOException

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

Specified by:

create in class FileSystem

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

getReplication

public short getReplication(Path src)
                     throws IOException

Get replication.

Specified by:

getReplication in class FileSystem

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.

Specified by:

setReplication in class FileSystem

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 boolean rename(Path src,
                      Path dst)
               throws IOException

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

Specified by:

rename in class FileSystem

Throws:

IOException

delete

public boolean delete(Path f)
               throws IOException

Delete a file

Specified by:

delete in class FileSystem

Throws:

IOException

exists

public boolean exists(Path f)
               throws IOException

Check if exists.

Specified by:

exists in class FileSystem

Parameters:

f - source file

Throws:

IOException

isDirectory

public boolean isDirectory(Path f)
                    throws IOException

True iff the named path is a directory.

Specified by:

isDirectory in class FileSystem

Throws:

IOException

getLength

public long getLength(Path f)
               throws IOException

The number of bytes in a file.

Specified by:

getLength in class FileSystem

Throws:

IOException

listPaths

public Path[] listPaths(Path f)
                 throws IOException

List files in a directory.

Specified by:

listPaths in class FileSystem

Throws:

IOException

setWorkingDirectory

public void setWorkingDirectory(Path newDir)

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

Specified by:

setWorkingDirectory in class FileSystem

Parameters:

newDir -

getWorkingDirectory

public Path getWorkingDirectory()

Get the current working directory for the given file system

Specified by:

getWorkingDirectory in class FileSystem

Returns:

the directory pathname

mkdirs

public boolean mkdirs(Path f)
               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.

Specified by:

mkdirs in class FileSystem

Throws:

IOException

lock

@Deprecated
public void lock(Path f,
                            boolean shared)
          throws IOException

Deprecated. FS does not support file locks anymore.

Obtain a lock on the given Path

Specified by:

lock in class FileSystem

Throws:

IOException

release

@Deprecated
public void release(Path f)
             throws IOException

Deprecated. FS does not support file locks anymore.

Release the lock

Specified by:

release in class FileSystem

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

Specified by:

copyFromLocalFile in class FileSystem

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.

Specified by:

copyToLocalFile in class FileSystem

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.

Specified by:

startLocalOutput in class FileSystem

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.

Specified by:

completeLocalOutput in class FileSystem

Throws:

IOException

getBlockSize

public long getBlockSize(Path f)
                  throws IOException

Get the block size for a particular file.

Specified by:

getBlockSize in class FileSystem

Parameters:

f - the filename

Returns:

the number of bytes in a block

Throws:

IOException

getDefaultBlockSize

public long getDefaultBlockSize()

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

Overrides:

getDefaultBlockSize in class FileSystem

getDefaultReplication

public short getDefaultReplication()

Get the default replication.

Specified by:

getDefaultReplication in class FileSystem

getConf

public Configuration getConf()

Description copied from interface: Configurable

Return the configuration used by this object.

Specified by:

getConf in interface Configurable

Overrides:

getConf in class Configured

close

public void close()
           throws IOException

Description copied from class: FileSystem

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

Overrides:

close in class FileSystem

Throws:

IOException