edu.iu.dsc.tws.api.data

Class FileSystem

java.lang.Object

edu.iu.dsc.tws.api.data.FileSystem

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

HadoopFileSystem, LocalFileSystem

public abstract class FileSystem
extends java.lang.Object
implements java.io.Serializable

This class is an abstract of the generic file system that will be used in the system This can be extend to support distributed file system or a local file system. This defines the basic set of operations that need to be supported by the concrete implementation

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FileSystem.WriteMode

Constructor Summary

Constructors

Constructor and Description
FileSystem()

Method Summary

Modifier and Type	Method and Description
abstract FSDataOutputStream	create(Path f) Create a file system with the OVERWRITE
abstract FSDataOutputStream	create(Path f, FileSystem.WriteMode writeMode) Create a file system with the specific write mdoe
abstract boolean	delete(Path f, boolean recursive)
boolean	exists(Path path) Check if the given path exsits
abstract long	getDefaultBlockSize()
abstract BlockLocation[]	getFileBlockLocations(FileStatus file, long start, long len) Return an array containing hostnames, offset and size of portions of the given file.
abstract FileStatus	getFileStatus(Path f) Return a file status object that represents the path.
abstract java.net.URI	getUri() Returns a URI whose scheme and authority identify this file system.
abstract Path	getWorkingDirectory() Get the working Directory
abstract void	initialize(java.net.URI name) Called after a new FileSystem instance is constructed.
boolean	isDirectory(Path path) Check if directory
abstract boolean	isDistributedFS()
boolean	isFile(Path path) Check if file
boolean	isSymlink(Path path) check if isSymlink
abstract FileStatus[]	listFiles(Path f) List the statuses of the files/directories in the given path if the path is a directory.
abstract FileStatus[]	listStatus(Path f)
abstract boolean	mkdirs(Path f)
abstract FSDataInputStream	open(Path f) Opens an FSDataInputStream at the indicated Path.
abstract FSDataInputStream	open(Path f, int bufferSize)
abstract boolean	rename(Path src, Path dst)
abstract void	setWorkingDirectory(Path path) Set the working Directory

Methods inherited from class java.lang.Object

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

Constructor Detail

FileSystem

public FileSystem()

Method Detail

isFile

public boolean isFile(Path path)

Check if file

isDirectory

public boolean isDirectory(Path path)

Check if directory

isSymlink

public boolean isSymlink(Path path)

check if isSymlink

setWorkingDirectory

public abstract void setWorkingDirectory(Path path)

Set the working Directory

getWorkingDirectory

public abstract Path getWorkingDirectory()

Get the working Directory

getUri

public abstract java.net.URI getUri()

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

Returns:

a URI whose scheme and authority identify this file system

initialize

public abstract void initialize(java.net.URI name)
                         throws java.io.IOException

Called after a new FileSystem instance is constructed.

Parameters:

name - a URI whose authority section names the host, port, etc. for this file system

Throws:

java.io.IOException

getFileStatus

public abstract FileStatus getFileStatus(Path f)
                                  throws java.io.IOException

Return a file status object that represents the path.

Parameters:

f - The path we want information from

Returns:

a FileStatus object

Throws:

java.io.FileNotFoundException - when the path does not exist; IOException see specific implementation

java.io.IOException

listFiles

public abstract FileStatus[] listFiles(Path f)
                                throws java.io.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

Throws:

java.io.IOException

open

public abstract FSDataInputStream open(Path f)
                                throws java.io.IOException

Opens an FSDataInputStream at the indicated Path.

Parameters:

f - the file to open

Throws:

java.io.IOException

exists

public boolean exists(Path path)
               throws java.io.IOException

Check if the given path exsits

Throws:

java.io.IOException

getFileBlockLocations

public abstract BlockLocation[] getFileBlockLocations(FileStatus file,
                                                      long start,
                                                      long len)
                                               throws java.io.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:

java.io.IOException

open

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

Throws:

java.io.IOException

create

public abstract FSDataOutputStream create(Path f)
                                   throws java.io.IOException

Create a file system with the OVERWRITE

Parameters:

f - path

Returns:

the output stream

Throws:

java.io.IOException - if an error occurs

create

public abstract FSDataOutputStream create(Path f,
                                          FileSystem.WriteMode writeMode)
                                   throws java.io.IOException

Create a file system with the specific write mdoe

Parameters:

f - path

writeMode - weather overwrite or not, when creating new files

Returns:

the output stream

Throws:

java.io.IOException - if an error occurs

delete

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

Throws:

java.io.IOException

listStatus

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

Throws:

java.io.IOException

mkdirs

public abstract boolean mkdirs(Path f)
                        throws java.io.IOException

Throws:

java.io.IOException

rename

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

Throws:

java.io.IOException

getDefaultBlockSize

public abstract long getDefaultBlockSize()

isDistributedFS

public abstract boolean isDistributedFS()