tachyon

Class UnderFileSystem

java.lang.Object

tachyon.UnderFileSystem

Direct Known Subclasses:

UnderFileSystemHdfs, UnderFileSystemSingleLocal

public abstract class UnderFileSystem
extends Object

Tachyon stores data into an under layer file system. Any file system implementing this interface can be a valid under layer file system

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	UnderFileSystem.SpaceType

Constructor Summary

Constructors

Constructor and Description
UnderFileSystem()

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	close()
abstract OutputStream	create(String path)
abstract OutputStream	create(String path, int blockSizeByte)
abstract OutputStream	create(String path, short replication, int blockSizeByte)
abstract boolean	delete(String path, boolean recursive)
abstract boolean	exists(String path)
static UnderFileSystem	get(String path) Get the UnderFileSystem instance according to its schema.
static UnderFileSystem	get(String path, Object conf) Get the UnderFileSystem instance according to its scheme and configuration.
abstract long	getBlockSizeByte(String path)
abstract Object	getConf() To get the configuration object for UnderFileSystem.
abstract List<String>	getFileLocations(String path)
abstract List<String>	getFileLocations(String path, long offset)
abstract long	getFileSize(String path)
abstract long	getModificationTimeMs(String path)
abstract long	getSpace(String path, UnderFileSystem.SpaceType type)
abstract boolean	isFile(String path)
abstract String[]	list(String path) Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.
abstract boolean	mkdirs(String path, boolean createParent) Creates the directory named by this abstract pathname.
abstract InputStream	open(String path)
static Pair<String,String>	parse(TachyonURI path) Transform an input string like hdfs://host:port/dir, hdfs://host:port, file:///dir, /dir into a pair of address and path.
abstract boolean	rename(String src, String dst)
abstract void	setConf(Object conf) To set the configuration object for UnderFileSystem.
abstract void	setPermission(String path, String posixPerm) Change posix file permission

Methods inherited from class java.lang.Object

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

Constructor Detail

UnderFileSystem

public UnderFileSystem()

Method Detail

get

public static UnderFileSystem get(String path)

Get the UnderFileSystem instance according to its schema.

Parameters:

path - file path storing over the ufs.

Returns:

instance of the under layer file system

Throws:

IllegalArgumentException - for unknown scheme

get

public static UnderFileSystem get(String path,
                  Object conf)

Get the UnderFileSystem instance according to its scheme and configuration.

Parameters:

path - file path storing over the ufs

conf - the configuration object for ufs only

Returns:

instance of the under layer file system

Throws:

IllegalArgumentException - for unknown scheme

parse

public static Pair<String,String> parse(TachyonURI path)

Transform an input string like hdfs://host:port/dir, hdfs://host:port, file:///dir, /dir into a pair of address and path. The returned pairs are ("hdfs://host:port", "/dir"), ("hdfs://host:port", "/"), and ("/", "/dir"), respectively.

Parameters:

path - the input path string

Returns:

null if path does not start with tachyon://, tachyon-ft://, hdfs://, s3://, s3n://, file://, /. Or a pair of strings denoting the under FS address and the relative path relative to that address. For local FS (with prefixes file:// or /), the under FS address is "/" and the path starts with "/".

close

public abstract void close()
                    throws IOException

Throws:

IOException

create

public abstract OutputStream create(String path)
                             throws IOException

Throws:

IOException

create

public abstract OutputStream create(String path,
                  int blockSizeByte)
                             throws IOException

Throws:

IOException

create

public abstract OutputStream create(String path,
                  short replication,
                  int blockSizeByte)
                             throws IOException

Throws:

IOException

delete

public abstract boolean delete(String path,
             boolean recursive)
                        throws IOException

Throws:

IOException

exists

public abstract boolean exists(String path)
                        throws IOException

Throws:

IOException

getBlockSizeByte

public abstract long getBlockSizeByte(String path)
                               throws IOException

Throws:

IOException

getConf

public abstract Object getConf()

To get the configuration object for UnderFileSystem.

Returns:

configuration object used for concrete ufs instance

getFileLocations

public abstract List<String> getFileLocations(String path)
                                       throws IOException

Throws:

IOException

getFileLocations

public abstract List<String> getFileLocations(String path,
                            long offset)
                                       throws IOException

Throws:

IOException

getFileSize

public abstract long getFileSize(String path)
                          throws IOException

Throws:

IOException

getModificationTimeMs

public abstract long getModificationTimeMs(String path)
                                    throws IOException

Throws:

IOException

getSpace

public abstract long getSpace(String path,
            UnderFileSystem.SpaceType type)
                       throws IOException

Throws:

IOException

isFile

public abstract boolean isFile(String path)
                        throws IOException

Throws:

IOException

list

public abstract String[] list(String path)
                       throws IOException

Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.

If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of strings is returned, one for each file or directory in the directory. Names denoting the directory itself and the directory's parent directory are not included in the result. Each string is a file name rather than a complete path.

There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order.

Parameters:

path - the path to list.

Returns:

An array of strings naming the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Throws:

IOException

mkdirs

public abstract boolean mkdirs(String path,
             boolean createParent)
                        throws IOException

Creates the directory named by this abstract pathname. If the folder already exists, the method returns false.

Parameters:

path - the folder to create

createParent - If true, the method creates any necessary but nonexistent parent directories. Otherwise, the method does not create nonexistent parent directories.

Returns:

true if and only if the directory was created; false otherwise

Throws:

IOException

open

public abstract InputStream open(String path)
                          throws IOException

Throws:

IOException

rename

public abstract boolean rename(String src,
             String dst)
                        throws IOException

Throws:

IOException

setConf

public abstract void setConf(Object conf)

To set the configuration object for UnderFileSystem. The conf object is understood by the concrete underfs's implementation.

Parameters:

conf - The configuration object accepted by ufs.

setPermission

public abstract void setPermission(String path,
                 String posixPerm)
                            throws IOException

Change posix file permission

Parameters:

path - path of the file

posixPerm - standard posix permission like "777", "775", etc.

Throws:

IOException