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:

Closeable, Configurable

Direct Known Subclasses:

ChecksumFileSystem, HarFileSystem

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.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.fs.FileSystem

FileSystem.Statistics

Field Summary

protected FileSystem

fs

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

FS_DEFAULT_NAME_KEY, LOG, statistics

Constructor Summary

FilterFileSystem()

FilterFileSystem(FileSystem fs)

Method Summary

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.
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	concat(Path f, Path[] psrcs) Concat existing files together.
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, FsPermission permission, 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) Deprecated.
boolean	delete(Path f, boolean recursive) Delete a file
String	getCanonicalServiceName() Get a canonical service name for this file system.
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.
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.
FileStatus	getFileStatus(Path f) Get file status.
Path	getHomeDirectory() Return the current user's home directory in this filesystem.
String	getName() Deprecated. call #getUri() instead.
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.
FileStatus[]	listStatus(Path f) List files in a directory.
Path	makeQualified(Path path) Make sure that a path specifies a FileSystem.
boolean	mkdirs(Path f, FsPermission permission) Make the given file and all non-existent parents into directories.
FSDataInputStream	open(Path f, int bufferSize) Opens an FSDataInputStream at the indicated Path.
boolean	rename(Path src, Path dst) Renames Path src to Path dst.
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	setVerifyChecksum(boolean verifyChecksum) Set the verify checksum flag.
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

addFileSystemForTesting, append, append, clearStatistics, closeAll, closeAllForUGI, copyFromLocalFile, copyFromLocalFile, copyFromLocalFile, copyToLocalFile, create, create, create, create, create, create, create, create, create, create, createNewFile, createNonRecursive, createNonRecursive, deleteOnExit, exists, get, get, get, getAllStatistics, getBlockSize, getCacheSize, getCanonicalUri, getContentSummary, getDefaultBlockSize, getDefaultPort, getDefaultReplication, getDefaultUri, getDelegationToken, getLength, getLocal, getNamed, getReplication, getStatistics, getStatistics, getUsed, globStatus, globStatus, isDirectory, isFile, listStatus, listStatus, listStatus, mkdirs, mkdirs, moveFromLocalFile, moveFromLocalFile, moveToLocalFile, open, printStatistics, processDeleteOnExit, setDefaultUri, setDefaultUri, setTimes

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()

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.

Overrides:

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

getCanonicalServiceName

public String getCanonicalServiceName()

Description copied from class: FileSystem

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.

Overrides:

getCanonicalServiceName in class FileSystem

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.

Overrides:

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

getFileBlockLocations

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

Description copied from class: FileSystem

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'.

Overrides:

getFileBlockLocations 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

append

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

Append to an existing file (optional operation).

Specified by:

append in class FileSystem

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 f,
                   Path[] psrcs)
            throws IOException

Description copied from class: FileSystem

Concat existing files together.

Overrides:

concat in class FileSystem

Parameters:

f - the path to the target destination.

Throws:

IOException

create

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

Description copied from class: FileSystem

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

See Also:

FileSystem.setPermission(Path, FsPermission)

setReplication

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

Set replication for an existing file.

Overrides:

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

@Deprecated
public boolean delete(Path f)
               throws IOException

Deprecated.

Delete a file

Specified by:

delete in class FileSystem

Throws:

IOException

delete

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

Delete a file

Specified by:

delete in class FileSystem

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

listStatus

public FileStatus[] listStatus(Path f)
                        throws IOException

List files in a directory.

Specified by:

listStatus in class FileSystem

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

getHomeDirectory

public Path getHomeDirectory()

Description copied from class: FileSystem

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

Overrides:

getHomeDirectory in class FileSystem

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,
                      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.

Specified by:

mkdirs 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

Overrides:

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.

Overrides:

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.

Overrides:

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.

Overrides:

completeLocalOutput in class FileSystem

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.

Overrides:

getDefaultReplication in class FileSystem

getFileStatus

public FileStatus getFileStatus(Path f)
                         throws IOException

Get file status.

Specified by:

getFileStatus in class FileSystem

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.

Overrides:

getFileChecksum in class FileSystem

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.

Overrides:

setVerifyChecksum 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.

Specified by:

close in interface Closeable

Overrides:

close in class FileSystem

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.

Overrides:

setOwner in class FileSystem

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

setPermission

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

Set permission of a path.

Overrides:

setPermission in class FileSystem

Throws:

IOException