org.apache.hadoop.fs

Class AbstractFileSystem

java.lang.Object

org.apache.hadoop.fs.AbstractFileSystem

Direct Known Subclasses:

ViewFs

@InterfaceAudience.Public
@InterfaceStability.Evolving
public abstract class AbstractFileSystem
extends Object

This class provides an interface for implementors of a Hadoop file system (analogous to the VFS of Unix). Applications do not access this class; instead they access files across all file systems using FileContext. Pathnames passed to AbstractFileSystem can be fully qualified URI that matches the "this" file system (ie same scheme and authority) or a Slash-relative name that is assumed to be relative to the root of the "this" file system .

Field Summary

Fields

Modifier and Type	Field and Description
protected FileSystem.Statistics	statistics The statistics for this file system.

Constructor Summary

Constructors

Constructor and Description
AbstractFileSystem(URI uri, String supportedScheme, boolean authorityNeeded, int defaultPort) Constructor to be called by subclasses.

Method Summary

Methods

Modifier and Type	Method and Description
void	checkPath(Path path) Check that a Path belongs to this FileSystem.
void	checkScheme(URI uri, String supportedScheme) Check that the Uri's scheme matches
static void	clearStatistics()
FSDataOutputStream	create(Path f, EnumSet<CreateFlag> createFlag, Options.CreateOpts... opts) The specification of this method matches that of FileContext.create(Path, EnumSet, Options.CreateOpts...) except that the Path f must be fully qualified and the permission is absolute (i.e.
static AbstractFileSystem	createFileSystem(URI uri, Configuration conf) Create a file system instance for the specified uri using the conf.
abstract FSDataOutputStream	createInternal(Path f, EnumSet<CreateFlag> flag, FsPermission absolutePermission, int bufferSize, short replication, long blockSize, Progressable progress, Options.ChecksumOpt checksumOpt, boolean createParent) The specification of this method matches that of create(Path, EnumSet, Options.CreateOpts...) except that the opts have been declared explicitly.
void	createSymlink(Path target, Path link, boolean createParent) The specification of this method matches that of FileContext.createSymlink(Path, Path, boolean);
abstract boolean	delete(Path f, boolean recursive) The specification of this method matches that of FileContext.delete(Path, boolean) except that Path f must be for this file system.
boolean	equals(Object other)
static AbstractFileSystem	get(URI uri, Configuration conf) The main factory method for creating a file system.
protected static Map<URI,FileSystem.Statistics>	getAllStatistics()
String	getCanonicalServiceName() Get a canonical name for this file system.
abstract BlockLocation[]	getFileBlockLocations(Path f, long start, long len) The specification of this method matches that of FileContext.getFileBlockLocations(Path, long, long) except that Path f must be for this file system.
abstract FileChecksum	getFileChecksum(Path f) The specification of this method matches that of FileContext.getFileChecksum(Path) except that Path f must be for this file system.
FileStatus	getFileLinkStatus(Path f) The specification of this method matches that of FileContext.getFileLinkStatus(Path) except that an UnresolvedLinkException may be thrown if a symlink is encountered in the path leading up to the final path component.
abstract FileStatus	getFileStatus(Path f) The specification of this method matches that of FileContext.getFileStatus(Path) except that an UnresolvedLinkException may be thrown if a symlink is encountered in the path.
abstract FsStatus	getFsStatus() The specification of this method matches that of FileContext.getFsStatus(Path).
FsStatus	getFsStatus(Path f) The specification of this method matches that of FileContext.getFsStatus(Path) except that Path f must be for this file system.
Path	getHomeDirectory() Return the current user's home directory in this file system.
Path	getInitialWorkingDirectory() Some file systems like LocalFileSystem have an initial workingDir that is used as the starting workingDir.
Path	getLinkTarget(Path f) The specification of this method matches that of FileContext.getLinkTarget(Path);
abstract FsServerDefaults	getServerDefaults() Return a set of server default configuration values.
FileSystem.Statistics	getStatistics()
protected static FileSystem.Statistics	getStatistics(URI uri) Get the statistics for a particular file system.
URI	getUri() Returns a URI whose scheme and authority identify this FileSystem.
abstract int	getUriDefaultPort() The default port of this file system.
String	getUriPath(Path p) Get the path-part of a pathname.
int	hashCode()
RemoteIterator<Path>	listCorruptFileBlocks(Path path)
RemoteIterator<LocatedFileStatus>	listLocatedStatus(Path f) The specification of this method matches that of FileContext.listLocatedStatus(Path) except that Path f must be for this file system.
abstract FileStatus[]	listStatus(Path f) The specification of this method matches that of FileContext.Util.listStatus(Path) except that Path f must be for this file system.
RemoteIterator<FileStatus>	listStatusIterator(Path f) The specification of this method matches that of FileContext.listStatus(Path) except that Path f must be for this file system.
Path	makeQualified(Path path) Make the path fully qualified to this file system
abstract void	mkdir(Path dir, FsPermission permission, boolean createParent) The specification of this method matches that of FileContext.mkdir(Path, FsPermission, boolean) except that the Path f must be fully qualified and the permission is absolute (i.e.
FSDataInputStream	open(Path f) The specification of this method matches that of FileContext.open(Path) except that Path f must be for this file system.
abstract FSDataInputStream	open(Path f, int bufferSize) The specification of this method matches that of FileContext.open(Path, int) except that Path f must be for this file system.
static void	printStatistics() Prints statistics for all file systems.
void	rename(Path src, Path dst, Options.Rename... options) The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system.
abstract void	renameInternal(Path src, Path dst) The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system and NO OVERWRITE is performed.
void	renameInternal(Path src, Path dst, boolean overwrite) The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system.
Path	resolvePath(Path p) Return the fully-qualified path of path f resolving the path through any internal symlinks or mount point
abstract void	setOwner(Path f, String username, String groupname) The specification of this method matches that of FileContext.setOwner(Path, String, String) except that Path f must be for this file system.
abstract void	setPermission(Path f, FsPermission permission) The specification of this method matches that of FileContext.setPermission(Path, FsPermission) except that Path f must be for this file system.
abstract boolean	setReplication(Path f, short replication) The specification of this method matches that of FileContext.setReplication(Path, short) except that Path f must be for this file system.
abstract void	setTimes(Path f, long mtime, long atime) The specification of this method matches that of FileContext.setTimes(Path, long, long) except that Path f must be for this file system.
abstract void	setVerifyChecksum(boolean verifyChecksum) The specification of this method matches that of FileContext.setVerifyChecksum(boolean, Path) except that Path f must be for this file system.
boolean	supportsSymlinks() Returns true if the file system supports symlinks, false otherwise.

Methods inherited from class java.lang.Object

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

Field Detail

statistics

protected FileSystem.Statistics statistics

The statistics for this file system.

Constructor Detail

AbstractFileSystem

public AbstractFileSystem(URI uri,
                  String supportedScheme,
                  boolean authorityNeeded,
                  int defaultPort)
                   throws URISyntaxException

Constructor to be called by subclasses.

Parameters:

uri - for this file system.

supportedScheme - the scheme supported by the implementor

authorityNeeded - if true then theURI must have authority, if false then the URI must have null authority.

Throws:

URISyntaxException - uri has syntax error

Method Detail

getStatistics

public FileSystem.Statistics getStatistics()

createFileSystem

public static AbstractFileSystem createFileSystem(URI uri,
                                  Configuration conf)
                                           throws UnsupportedFileSystemException

Create a file system instance for the specified uri using the conf. The conf is used to find the class name that implements the file system. The conf is also passed to the file system for its configuration.

Parameters:

uri - URI of the file system

conf - Configuration for the file system

Returns:

Returns the file system for the given URI

Throws:

UnsupportedFileSystemException - file system for uri is not found

getStatistics

protected static FileSystem.Statistics getStatistics(URI uri)

Get the statistics for a particular file system.

Parameters:

uri - used as key to lookup STATISTICS_TABLE. Only scheme and authority part of the uri are used.

Returns:

a statistics object

clearStatistics

public static void clearStatistics()

printStatistics

public static void printStatistics()

Prints statistics for all file systems.

getAllStatistics

protected static Map<URI,FileSystem.Statistics> getAllStatistics()

get

public static AbstractFileSystem get(URI uri,
                     Configuration conf)
                              throws UnsupportedFileSystemException

The main factory method for creating a file system. Get a file system for the URI's scheme and authority. The scheme of the uri determines a configuration property name, fs.AbstractFileSystem.scheme.impl whose value names the AbstractFileSystem class. The entire URI and conf is passed to the AbstractFileSystem factory method.

Parameters:

uri - for the file system to be created.

conf - which is passed to the file system impl.

Returns:

file system for the given URI.

Throws:

UnsupportedFileSystemException - if the file system for uri is not supported.

checkScheme

public void checkScheme(URI uri,
               String supportedScheme)

Check that the Uri's scheme matches

Parameters:

uri -

supportedScheme -

getUriDefaultPort

public abstract int getUriDefaultPort()

The default port of this file system.

Returns:

default port of this file system's Uri scheme A uri with a port of -1 => default port;

getUri

public URI getUri()

Returns a URI whose scheme and authority identify this FileSystem.

Returns:

the uri of this file system.

checkPath

public void checkPath(Path path)

Check that a Path belongs to this FileSystem. If the path is fully qualified URI, then its scheme and authority matches that of this file system. Otherwise the path must be slash-relative name.

Throws:

InvalidPathException - if the path is invalid

getUriPath

public String getUriPath(Path p)

Get the path-part of a pathname. Checks that URI matches this file system and that the path-part is a valid name.

Parameters:

p - path

Returns:

path-part of the Path p

makeQualified

public Path makeQualified(Path path)

Make the path fully qualified to this file system

Parameters:

path -

Returns:

the qualified path

getInitialWorkingDirectory

public Path getInitialWorkingDirectory()

Some file systems like LocalFileSystem have an initial workingDir that is used as the starting workingDir. For other file systems like HDFS there is no built in notion of an initial workingDir.

Returns:

the initial workingDir if the file system has such a notion otherwise return a null.

getHomeDirectory

public Path getHomeDirectory()

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

Returns:

current user's home directory.

getServerDefaults

public abstract FsServerDefaults getServerDefaults()
                                            throws IOException

Return a set of server default configuration values.

Returns:

server default configuration values

Throws:

IOException - an I/O error occurred

resolvePath

public Path resolvePath(Path p)
                 throws FileNotFoundException,
                        org.apache.hadoop.fs.UnresolvedLinkException,
                        org.apache.hadoop.security.AccessControlException,
                        IOException

Return the fully-qualified path of path f resolving the path through any internal symlinks or mount point

Parameters:

p - path to be resolved

Returns:

fully qualified path

Throws:

FileNotFoundException, - AccessControlException, IOException UnresolvedLinkException if symbolic link on path cannot be resolved internally

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

org.apache.hadoop.security.AccessControlException

IOException

create

public final FSDataOutputStream create(Path f,
                        EnumSet<CreateFlag> createFlag,
                        Options.CreateOpts... opts)
                                throws org.apache.hadoop.security.AccessControlException,
                                       FileAlreadyExistsException,
                                       FileNotFoundException,
                                       ParentNotDirectoryException,
                                       UnsupportedFileSystemException,
                                       org.apache.hadoop.fs.UnresolvedLinkException,
                                       IOException

The specification of this method matches that of FileContext.create(Path, EnumSet, Options.CreateOpts...) except that the Path f must be fully qualified and the permission is absolute (i.e. umask has been applied).

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

UnsupportedFileSystemException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

createInternal

public abstract FSDataOutputStream createInternal(Path f,
                                EnumSet<CreateFlag> flag,
                                FsPermission absolutePermission,
                                int bufferSize,
                                short replication,
                                long blockSize,
                                Progressable progress,
                                Options.ChecksumOpt checksumOpt,
                                boolean createParent)
                                           throws org.apache.hadoop.security.AccessControlException,
                                                  FileAlreadyExistsException,
                                                  FileNotFoundException,
                                                  ParentNotDirectoryException,
                                                  UnsupportedFileSystemException,
                                                  org.apache.hadoop.fs.UnresolvedLinkException,
                                                  IOException

The specification of this method matches that of create(Path, EnumSet, Options.CreateOpts...) except that the opts have been declared explicitly.

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

UnsupportedFileSystemException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

mkdir

public abstract void mkdir(Path dir,
         FsPermission permission,
         boolean createParent)
                    throws org.apache.hadoop.security.AccessControlException,
                           FileAlreadyExistsException,
                           FileNotFoundException,
                           org.apache.hadoop.fs.UnresolvedLinkException,
                           IOException

The specification of this method matches that of FileContext.mkdir(Path, FsPermission, boolean) except that the Path f must be fully qualified and the permission is absolute (i.e. umask has been applied).

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

delete

public abstract boolean delete(Path f,
             boolean recursive)
                        throws org.apache.hadoop.security.AccessControlException,
                               FileNotFoundException,
                               org.apache.hadoop.fs.UnresolvedLinkException,
                               IOException

The specification of this method matches that of FileContext.delete(Path, boolean) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

open

public FSDataInputStream open(Path f)
                       throws org.apache.hadoop.security.AccessControlException,
                              FileNotFoundException,
                              org.apache.hadoop.fs.UnresolvedLinkException,
                              IOException

The specification of this method matches that of FileContext.open(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

open

public abstract FSDataInputStream open(Path f,
                     int bufferSize)
                                throws org.apache.hadoop.security.AccessControlException,
                                       FileNotFoundException,
                                       org.apache.hadoop.fs.UnresolvedLinkException,
                                       IOException

The specification of this method matches that of FileContext.open(Path, int) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setReplication

public abstract boolean setReplication(Path f,
                     short replication)
                                throws org.apache.hadoop.security.AccessControlException,
                                       FileNotFoundException,
                                       org.apache.hadoop.fs.UnresolvedLinkException,
                                       IOException

The specification of this method matches that of FileContext.setReplication(Path, short) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

rename

public final void rename(Path src,
          Path dst,
          Options.Rename... options)
                  throws org.apache.hadoop.security.AccessControlException,
                         FileAlreadyExistsException,
                         FileNotFoundException,
                         ParentNotDirectoryException,
                         org.apache.hadoop.fs.UnresolvedLinkException,
                         IOException

The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

renameInternal

public abstract void renameInternal(Path src,
                  Path dst)
                             throws org.apache.hadoop.security.AccessControlException,
                                    FileAlreadyExistsException,
                                    FileNotFoundException,
                                    ParentNotDirectoryException,
                                    org.apache.hadoop.fs.UnresolvedLinkException,
                                    IOException

The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system and NO OVERWRITE is performed. File systems that do not have a built in overwrite need implement only this method and can take advantage of the default impl of the other renameInternal(Path, Path, boolean)

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

renameInternal

public void renameInternal(Path src,
                  Path dst,
                  boolean overwrite)
                    throws org.apache.hadoop.security.AccessControlException,
                           FileAlreadyExistsException,
                           FileNotFoundException,
                           ParentNotDirectoryException,
                           org.apache.hadoop.fs.UnresolvedLinkException,
                           IOException

The specification of this method matches that of FileContext.rename(Path, Path, Options.Rename...) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

supportsSymlinks

public boolean supportsSymlinks()

Returns true if the file system supports symlinks, false otherwise.

createSymlink

public void createSymlink(Path target,
                 Path link,
                 boolean createParent)
                   throws IOException,
                          org.apache.hadoop.fs.UnresolvedLinkException

The specification of this method matches that of FileContext.createSymlink(Path, Path, boolean);

Throws:

IOException

org.apache.hadoop.fs.UnresolvedLinkException

getLinkTarget

public Path getLinkTarget(Path f)
                   throws IOException

The specification of this method matches that of FileContext.getLinkTarget(Path);

Throws:

IOException

setPermission

public abstract void setPermission(Path f,
                 FsPermission permission)
                            throws org.apache.hadoop.security.AccessControlException,
                                   FileNotFoundException,
                                   org.apache.hadoop.fs.UnresolvedLinkException,
                                   IOException

The specification of this method matches that of FileContext.setPermission(Path, FsPermission) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setOwner

public abstract void setOwner(Path f,
            String username,
            String groupname)
                       throws org.apache.hadoop.security.AccessControlException,
                              FileNotFoundException,
                              org.apache.hadoop.fs.UnresolvedLinkException,
                              IOException

The specification of this method matches that of FileContext.setOwner(Path, String, String) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setTimes

public abstract void setTimes(Path f,
            long mtime,
            long atime)
                       throws org.apache.hadoop.security.AccessControlException,
                              FileNotFoundException,
                              org.apache.hadoop.fs.UnresolvedLinkException,
                              IOException

The specification of this method matches that of FileContext.setTimes(Path, long, long) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFileChecksum

public abstract FileChecksum getFileChecksum(Path f)
                                      throws org.apache.hadoop.security.AccessControlException,
                                             FileNotFoundException,
                                             org.apache.hadoop.fs.UnresolvedLinkException,
                                             IOException

The specification of this method matches that of FileContext.getFileChecksum(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFileStatus

public abstract FileStatus getFileStatus(Path f)
                                  throws org.apache.hadoop.security.AccessControlException,
                                         FileNotFoundException,
                                         org.apache.hadoop.fs.UnresolvedLinkException,
                                         IOException

The specification of this method matches that of FileContext.getFileStatus(Path) except that an UnresolvedLinkException may be thrown if a symlink is encountered in the path.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFileLinkStatus

public FileStatus getFileLinkStatus(Path f)
                             throws org.apache.hadoop.security.AccessControlException,
                                    FileNotFoundException,
                                    UnsupportedFileSystemException,
                                    IOException

The specification of this method matches that of FileContext.getFileLinkStatus(Path) except that an UnresolvedLinkException may be thrown if a symlink is encountered in the path leading up to the final path component. If the file system does not support symlinks then the behavior is equivalent to getFileStatus(Path).

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

UnsupportedFileSystemException

IOException

getFileBlockLocations

public abstract BlockLocation[] getFileBlockLocations(Path f,
                                    long start,
                                    long len)
                                               throws org.apache.hadoop.security.AccessControlException,
                                                      FileNotFoundException,
                                                      org.apache.hadoop.fs.UnresolvedLinkException,
                                                      IOException

The specification of this method matches that of FileContext.getFileBlockLocations(Path, long, long) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFsStatus

public FsStatus getFsStatus(Path f)
                     throws org.apache.hadoop.security.AccessControlException,
                            FileNotFoundException,
                            org.apache.hadoop.fs.UnresolvedLinkException,
                            IOException

The specification of this method matches that of FileContext.getFsStatus(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFsStatus

public abstract FsStatus getFsStatus()
                              throws org.apache.hadoop.security.AccessControlException,
                                     FileNotFoundException,
                                     IOException

The specification of this method matches that of FileContext.getFsStatus(Path).

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

IOException

listStatusIterator

public RemoteIterator<FileStatus> listStatusIterator(Path f)
                                              throws org.apache.hadoop.security.AccessControlException,
                                                     FileNotFoundException,
                                                     org.apache.hadoop.fs.UnresolvedLinkException,
                                                     IOException

The specification of this method matches that of FileContext.listStatus(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listLocatedStatus

public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
                                                    throws org.apache.hadoop.security.AccessControlException,
                                                           FileNotFoundException,
                                                           org.apache.hadoop.fs.UnresolvedLinkException,
                                                           IOException

The specification of this method matches that of FileContext.listLocatedStatus(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listStatus

public abstract FileStatus[] listStatus(Path f)
                                 throws org.apache.hadoop.security.AccessControlException,
                                        FileNotFoundException,
                                        org.apache.hadoop.fs.UnresolvedLinkException,
                                        IOException

The specification of this method matches that of FileContext.Util.listStatus(Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listCorruptFileBlocks

public RemoteIterator<Path> listCorruptFileBlocks(Path path)
                                           throws IOException

Returns:

an iterator over the corrupt files under the given path (may contain duplicates if a file has more than one corrupt block)

Throws:

IOException

setVerifyChecksum

public abstract void setVerifyChecksum(boolean verifyChecksum)
                                throws org.apache.hadoop.security.AccessControlException,
                                       IOException

The specification of this method matches that of FileContext.setVerifyChecksum(boolean, Path) except that Path f must be for this file system.

Throws:

org.apache.hadoop.security.AccessControlException

IOException

getCanonicalServiceName

public String getCanonicalServiceName()

Get a canonical name for this file system.

Returns:

a URI string that uniquely identifies this file system

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object