Package org.apache.flink.core.fs.local

Class LocalFileSystem

java.lang.Object

org.apache.flink.core.fs.FileSystem

org.apache.flink.core.fs.local.LocalFileSystem

@Internal
public class LocalFileSystem
extends FileSystem

The class LocalFileSystem is an implementation of the FileSystem interface for the local file system of the machine where the JVM runs.

Nested Class Summary

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

FileSystem.WriteMode

Constructor Summary

Constructors

Constructor	Description
LocalFileSystem()	Constructs a new LocalFileSystem object.

Method Summary

Modifier and Type	Method	Description
FSDataOutputStream	create(Path filePath, FileSystem.WriteMode overwrite)	Opens an FSDataOutputStream to a new file at the given path.
LocalRecoverableWriter	createRecoverableWriter()	Creates a new RecoverableWriter.
boolean	delete(Path f, boolean recursive)	Delete a file.
boolean	exists(Path f)	Check if exists.
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.
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.
static URI	getLocalFsURI()	Gets the URI that represents the local file system.
static LocalFileSystem	getSharedInstance()	Gets the shared instance 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)	Recursively creates the directory specified by the provided path.
FSDataInputStream	open(Path f)	Opens an FSDataInputStream at the indicated Path.
FSDataInputStream	open(Path f, int bufferSize)	Opens an FSDataInputStream at the indicated Path.
File	pathToFile(Path path)	Converts the given Path to a File for this file system.
boolean	rename(Path src, Path dst)	Renames the file/directory src to dst.

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

create, create, get, getDefaultBlockSize, 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

LocalFileSystem

public LocalFileSystem()

Constructs a new LocalFileSystem object.

Method Detail

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

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

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

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.

open

public FSDataInputStream 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 FSDataInputStream 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

createRecoverableWriter

public LocalRecoverableWriter 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.

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

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

mkdirs

public boolean mkdirs(Path f)
               throws IOException

Recursively creates the directory specified by the provided path.

Specified by:

mkdirs in class FileSystem

Parameters:

f - the directory/directories to be created

Returns:

trueif the directories either already existed or have been created successfully, false otherwise

Throws:

IOException - thrown if an error occurred while creating the directory/directories

create

public FSDataOutputStream create(Path filePath,
                                 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:

filePath - 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.

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

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

pathToFile

public File pathToFile(Path path)

Converts the given Path to a File for this file system. If the path is empty, we will return new File(".") instead of new File(""), since the latter returns false for isDirectory judgement (See issue https://issues.apache.org/jira/browse/FLINK-18612).

getLocalFsURI

public static URI getLocalFsURI()

Gets the URI that represents the local file system. That URI is "file:/" on Windows platforms and "file:///" on other UNIX family platforms.

Returns:

The URI that represents the local file system.

getSharedInstance

public static LocalFileSystem getSharedInstance()

Gets the shared instance of this file system.

Returns:

The shared instance of this file system.