org.apache.flink.runtime.fs.hdfs

Class HadoopFileSystem

java.lang.Object

org.apache.flink.core.fs.FileSystem

org.apache.flink.runtime.fs.hdfs.HadoopFileSystem

Direct Known Subclasses:

FlinkOSSFileSystem, FlinkS3FileSystem

public class HadoopFileSystem
extends FileSystem

A FileSystem that wraps an Hadoop File System.

Nested Class Summary

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

FileSystem.WriteMode

Constructor Summary

Constructors

Constructor and Description
HadoopFileSystem(org.apache.hadoop.fs.FileSystem hadoopFileSystem) Wraps the given Hadoop File System object as a Flink File System object.

Method Summary

Modifier and Type	Method and Description
HadoopDataOutputStream	create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize) Opens an FSDataOutputStream at the indicated Path.
HadoopDataOutputStream	create(Path f, FileSystem.WriteMode overwrite) Opens an FSDataOutputStream to a new file at the given path.
RecoverableWriter	createRecoverableWriter() Creates a new RecoverableWriter.
boolean	delete(Path f, boolean recursive) Delete a file.
boolean	exists(Path f) Check if exists.
long	getDefaultBlockSize() Return the number of bytes that large input files should be optimally be split into to minimize I/O time.
BlockLocation[]	getFileBlockLocations(FileStatus file, long start, long len) Return an array containing hostnames, offset and size of portions of the given file.
FileStatus	getFileStatus(Path f) Return a file status object that represents the path.
org.apache.hadoop.fs.FileSystem	getHadoopFileSystem() Gets the underlying Hadoop FileSystem.
Path	getHomeDirectory() Returns the path of the user's home directory in this file system.
FileSystemKind	getKind() Gets a description of the characteristics of this file system.
URI	getUri() Returns a URI whose scheme and authority identify this file system.
Path	getWorkingDirectory() Returns the path of the file system's current working directory.
boolean	isDistributedFS() Returns true if this is a distributed file system.
FileStatus[]	listStatus(Path f) List the statuses of the files/directories in the given path if the path is a directory.
boolean	mkdirs(Path f) Make the given file and all non-existent parents into directories.
HadoopDataInputStream	open(Path f) Opens an FSDataInputStream at the indicated Path.
HadoopDataInputStream	open(Path f, int bufferSize) Opens an FSDataInputStream at the indicated Path.
boolean	rename(Path src, Path dst) Renames the file/directory src to dst.
static org.apache.hadoop.fs.Path	toHadoopPath(Path path)

Methods inherited from class org.apache.flink.core.fs.FileSystem

create, get, getDefaultFsUri, getLocalFileSystem, getUnguardedFileSystem, initialize, initialize, initOutPathDistFS, initOutPathLocalFS

Methods inherited from class java.lang.Object

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

Constructor Detail

HadoopFileSystem

public HadoopFileSystem(org.apache.hadoop.fs.FileSystem hadoopFileSystem)

Wraps the given Hadoop File System object as a Flink File System object. The given Hadoop file system object is expected to be initialized already.

Parameters:

hadoopFileSystem - The Hadoop FileSystem that will be used under the hood.

Method Detail

getHadoopFileSystem

public org.apache.hadoop.fs.FileSystem getHadoopFileSystem()

Gets the underlying Hadoop FileSystem.

Returns:

The underlying Hadoop FileSystem.

getWorkingDirectory

public Path getWorkingDirectory()

Description copied from class: FileSystem

Returns the path of the file system's current working directory.

Specified by:

getWorkingDirectory in class FileSystem

Returns:

the path of the file system's current working directory

getHomeDirectory

public Path getHomeDirectory()

Description copied from class: FileSystem

Returns the path of the user's home directory in this file system.

Specified by:

getHomeDirectory in class FileSystem

Returns:

the path of the user's home directory in this file system.

getUri

public URI getUri()

Description copied from class: FileSystem

Returns a URI whose scheme and authority identify this file system.

Specified by:

getUri in class FileSystem

Returns:

a URI whose scheme and authority identify this file system

getFileStatus

public FileStatus getFileStatus(Path f)
                         throws IOException

Description copied from class: FileSystem

Return a file status object that represents the path.

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

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'.

Specified by:

getFileBlockLocations in class FileSystem

Throws:

IOException

open

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

Description copied from class: FileSystem

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

open

public HadoopDataInputStream open(Path f)
                           throws IOException

Description copied from class: FileSystem

Opens an FSDataInputStream at the indicated Path.

Specified by:

open in class FileSystem

Parameters:

f - the file to open

Throws:

IOException

create

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

Description copied from class: FileSystem

Opens an FSDataOutputStream at the indicated Path.

This method is deprecated, because most of its parameters are ignored by most file systems. To control for example the replication factor and block size in the Hadoop Distributed File system, make sure that the respective Hadoop configuration file is either linked from the Flink configuration, or in the classpath of either Flink or the user code.

Overrides:

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.

blockSize - the size of the file blocks

Throws:

IOException - Thrown, if the stream could not be opened because of an I/O, or because a file already exists at that path and the write mode indicates to not overwrite the file.

create

public HadoopDataOutputStream create(Path f,
                                     FileSystem.WriteMode overwrite)
                              throws IOException

Description copied from class: FileSystem

Opens an FSDataOutputStream to a new file at the given path.

If the file already exists, the behavior depends on the given WriteMode. If the mode is set to FileSystem.WriteMode.NO_OVERWRITE, then this method fails with an exception.

Specified by:

create in class FileSystem

Parameters:

f - The file path to write to

overwrite - The action to take if a file or directory already exists at the given path.

Returns:

The stream to the new file at the target path.

Throws:

IOException - Thrown, if the stream could not be opened because of an I/O, or because a file already exists at that path and the write mode indicates to not overwrite the file.

delete

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

Description copied from class: FileSystem

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, false otherwise

Throws:

IOException

exists

public boolean exists(Path f)
               throws IOException

Description copied from class: FileSystem

Check if exists.

Overrides:

exists in class FileSystem

Parameters:

f - source file

Throws:

IOException

listStatus

public FileStatus[] listStatus(Path f)
                        throws IOException

Description copied from class: FileSystem

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

Specified by:

listStatus in class FileSystem

Parameters:

f - given path

Returns:

the statuses of the files/directories in the given path

Throws:

IOException

mkdirs

public boolean mkdirs(Path f)
               throws IOException

Description copied from class: FileSystem

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

Parameters:

f - the directory/directories to be created

Returns:

true if at least one new directory has been created, false otherwise

Throws:

IOException - thrown if an I/O error occurs while creating the directory

rename

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

Description copied from class: FileSystem

Renames the file/directory src to dst.

Specified by:

rename in class FileSystem

Parameters:

src - the file/directory to rename

dst - the new name of the file/directory

Returns:

true if the renaming was successful, false otherwise

Throws:

IOException

getDefaultBlockSize

public long getDefaultBlockSize()

Description copied from class: FileSystem

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

Returns:

the number of bytes that large input files should be optimally be split into to minimize I/O time

isDistributedFS

public boolean isDistributedFS()

Description copied from class: FileSystem

Returns true if this is a distributed file system. A distributed file system here means that the file system is shared among all Flink processes that participate in a cluster or job and that all these processes can see the same files.

Specified by:

isDistributedFS in class FileSystem

Returns:

True, if this is a distributed file system, false otherwise.

getKind

public FileSystemKind getKind()

Description copied from class: FileSystem

Gets a description of the characteristics of this file system.

Specified by:

getKind in class FileSystem

createRecoverableWriter

public RecoverableWriter createRecoverableWriter()
                                          throws IOException

Description copied from class: FileSystem

Creates a new RecoverableWriter. A recoverable writer creates streams that can persist and recover their intermediate state. Persisting and recovering intermediate state is a core building block for writing to files that span multiple checkpoints.

The returned object can act as a shared factory to open and recover multiple streams.

This method is optional on file systems and various file system implementations may not support this method, throwing an UnsupportedOperationException.

Overrides:

createRecoverableWriter in class FileSystem

Returns:

A RecoverableWriter for this file system.

Throws:

IOException - Thrown, if the recoverable writer cannot be instantiated.

toHadoopPath

public static org.apache.hadoop.fs.Path toHadoopPath(Path path)