Package org.apache.hadoop.fs

Class AbstractFileSystem

java.lang.Object

org.apache.hadoop.fs.AbstractFileSystem

All Implemented Interfaces:

PathCapabilities

Direct Known Subclasses:

DelegateToFileSystem, FilterFs, ViewFs

@Public
@Stable
public abstract class AbstractFileSystem
extends Object
implements PathCapabilities

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	Description
protected FileSystem.Statistics	statistics	The statistics for this file system.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
void	access(Path path, FsAction mode)	The specification of this method matches that of FileContext.access(Path, FsAction) except that an UnresolvedLinkException may be thrown if a symlink is encountered in the path.
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()
final 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. umask has been applied).
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.
MultipartUploaderBuilder	createMultipartUploader(Path basePath)	Create a multipart uploader.
Path	createSnapshot(Path path, String snapshotName)	The specification of this method matches that of FileContext.createSnapshot(Path, String).
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.
void	deleteSnapshot(Path snapshotDir, String snapshotName)	The specification of this method matches that of FileContext.deleteSnapshot(Path, String).
boolean	equals(Object other)
static AbstractFileSystem	get(URI uri, Configuration conf)	The main factory method for creating a file system.
AclStatus	getAclStatus(Path path)	Gets the ACLs of files and directories.
protected static Map<URI,FileSystem.Statistics>	getAllStatistics()
Collection<? extends BlockStoragePolicySpi>	getAllStoragePolicies()	Retrieve all the storage policies supported by this file system.
String	getCanonicalServiceName()	Get a canonical name for this file system.
List<Token<?>>	getDelegationTokens(String renewer)	Get one or more delegation tokens associated with the filesystem.
Path	getEnclosingRoot(Path path)	Return path of the enclosing root for a given path The enclosing root path is a common ancestor that should be used for temp and staging dirs as well as within encryption zones and other restricted directories.
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)	Partially resolves the path.
abstract FsServerDefaults	getServerDefaults()	Deprecated. use getServerDefaults(Path) instead
FsServerDefaults	getServerDefaults(Path f)	Return a set of server default configuration values based on path.
FileSystem.Statistics	getStatistics()
protected static FileSystem.Statistics	getStatistics(URI uri)	Get the statistics for a particular file system.
BlockStoragePolicySpi	getStoragePolicy(Path src)	Retrieve the storage policy for a given file or directory.
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.
byte[]	getXAttr(Path path, String name)	Get an xattr for a file or directory.
Map<String,byte[]>	getXAttrs(Path path)	Get all of the xattrs for a file or directory.
Map<String,byte[]>	getXAttrs(Path path, List<String> names)	Get all of the xattrs for a file or directory.
int	hashCode()
boolean	hasPathCapability(Path path, String capability)	Probe for a specific capability under the given path.
boolean	isValidName(String src)	Returns true if the specified string is considered valid in the path part of a URI by this file system.
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.
List<String>	listXAttrs(Path path)	Get all of the xattr names for a file or directory.
Path	makeQualified(Path path)	Make the path fully qualified to this file system
protected final void	methodNotSupported()	Helper method that throws an UnsupportedOperationException for the current FileSystem method being called.
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.
void	modifyAclEntries(Path path, List<AclEntry> aclSpec)	Modifies ACL entries of files and directories.
void	msync()	Synchronize client metadata state.
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.
CompletableFuture<FSDataInputStream>	openFileWithOptions(Path path, OpenFileParameters parameters)	Open a file with the given set of options.
static void	printStatistics()	Prints statistics for all file systems.
void	removeAcl(Path path)	Removes all but the base ACL entries of files and directories.
void	removeAclEntries(Path path, List<AclEntry> aclSpec)	Removes ACL entries from files and directories.
void	removeDefaultAcl(Path path)	Removes all default ACL entries from files and directories.
void	removeXAttr(Path path, String name)	Remove an xattr of a file or directory.
final 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.
void	renameSnapshot(Path path, String snapshotOldName, String snapshotNewName)	The specification of this method matches that of FileContext.renameSnapshot(Path, String, String).
Path	resolvePath(Path p)	Return the fully-qualified path of path f resolving the path through any internal symlinks or mount point
void	satisfyStoragePolicy(Path path)	Set the source path to satisfy storage policy.
void	setAcl(Path path, List<AclEntry> aclSpec)	Fully replaces ACL of files and directories, discarding all existing entries.
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.
void	setStoragePolicy(Path path, String policyName)	Set the storage policy for a given file or directory.
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.
void	setXAttr(Path path, String name, byte[] value)	Set an xattr of a file or directory.
void	setXAttr(Path path, String name, byte[] value, EnumSet<XAttrSetFlag> flag)	Set an xattr of a file or directory.
boolean	supportsSymlinks()	Returns true if the file system supports symlinks, false otherwise.
boolean	truncate(Path f, long newLength)	The specification of this method matches that of FileContext.truncate(Path, long) except that Path f must be for this file system.
void	unsetStoragePolicy(Path src)	Unset the storage policy set for a given file or directory.

Methods inherited from class java.lang.Object

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

Field Details

statistics

protected FileSystem.Statistics statistics

The statistics for this file system.

Constructor Details

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.

defaultPort - default port to use if port is not specified in the URI.

Throws:

URISyntaxException - uri has syntax error

Method Details

getStatistics

public FileSystem.Statistics getStatistics()

isValidName

public boolean isValidName(String src)

Returns true if the specified string is considered valid in the path part of a URI by this file system. The default implementation enforces the rules of HDFS, but subclasses may override this method to implement specific validation rules for specific file systems.

Parameters:

src - String source filename to check, path part of the URI

Returns:

boolean true if the specified string is considered valid

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 - name URI of the FS.

supportedScheme - supported scheme.

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.

Parameters:

path - the path.

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 - the 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

@Deprecated
public abstract FsServerDefaults getServerDefaults()
                                            throws IOException

Deprecated.

use getServerDefaults(Path) instead

Return a set of server default configuration values.

Returns:

server default configuration values

Throws:

IOException - an I/O error occurred

getServerDefaults

public FsServerDefaults getServerDefaults(Path f)
                                   throws IOException

Return a set of server default configuration values based on path.

Parameters:

f - path to fetch server defaults

Returns:

server default configuration values for path

Throws:

IOException - an I/O error occurred

resolvePath

public Path resolvePath(Path p)
                 throws FileNotFoundException,
UnresolvedLinkException,
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 - when file not find throw.

AccessControlException - when accees control error throw.

IOException - raised on errors performing I/O.

UnresolvedLinkException - if symbolic link on path cannot be resolved internally

create

public final FSDataOutputStream create(Path f,
 EnumSet<CreateFlag> createFlag,
 Options.CreateOpts... opts)
                                throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
UnsupportedFileSystemException,
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).

Parameters:

f - the path.

createFlag - create_flag.

opts - create ops.

Returns:

output stream.

Throws:

AccessControlException - access controll exception.

FileAlreadyExistsException - file already exception.

FileNotFoundException - file not found exception.

ParentNotDirectoryException - parent not dir exception.

UnsupportedFileSystemException - unsupported file system exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

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 AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
UnsupportedFileSystemException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

flag - create flag.

absolutePermission - absolute permission.

bufferSize - buffer size.

replication - replications.

blockSize - block size.

progress - progress.

checksumOpt - check sum opt.

createParent - create parent.

Returns:

output stream.

Throws:

AccessControlException - access control exception.

FileAlreadyExistsException - file already exists exception.

FileNotFoundException - file not found exception.

ParentNotDirectoryException - parent not directory exception.

UnsupportedFileSystemException - unsupported filesystem exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

mkdir

public abstract void mkdir(Path dir,
 FsPermission permission,
 boolean createParent)
                    throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
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).

Parameters:

dir - directory.

permission - permission.

createParent - create parent flag.

Throws:

AccessControlException - access control exception.

FileAlreadyExistsException - file already exists exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

delete

public abstract boolean delete(Path f,
 boolean recursive)
                        throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

recursive - recursive flag.

Returns:

if successfully deleted success true, not false.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

open

public FSDataInputStream open(Path f)
                       throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

Returns:

input stream.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

open

public abstract FSDataInputStream open(Path f,
 int bufferSize)
                                throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

bufferSize - buffer size.

Returns:

if successfully open success true, not false.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

truncate

public boolean truncate(Path f,
 long newLength)
                 throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

newLength - new length.

Returns:

if successfully truncate success true, not false.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

setReplication

public abstract boolean setReplication(Path f,
 short replication)
                                throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

replication - replication.

Returns:

if successfully set replication success true, not false.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

rename

public final void rename(Path src,
 Path dst,
 Options.Rename... options)
                  throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
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.

Parameters:

src - src.

dst - dst.

options - options.

Throws:

AccessControlException - access control exception.

FileAlreadyExistsException - file already exists exception.

FileNotFoundException - file not found exception.

ParentNotDirectoryException - parent not directory exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

renameInternal

public abstract void renameInternal(Path src,
 Path dst)
                             throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
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)

Parameters:

src - src.

dst - dst.

Throws:

AccessControlException - access control exception.

FileAlreadyExistsException - file already exists exception.

FileNotFoundException - file not found exception.

ParentNotDirectoryException - parent not directory exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

renameInternal

public void renameInternal(Path src,
 Path dst,
 boolean overwrite)
                    throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
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.

Parameters:

src - src.

dst - dst.

overwrite - overwrite flag.

Throws:

AccessControlException - access control exception.

FileAlreadyExistsException - file already exists exception.

FileNotFoundException - file not found exception.

ParentNotDirectoryException - parent not directory exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

supportsSymlinks

public boolean supportsSymlinks()

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

Returns:

true if filesystem supports symlinks

createSymlink

public void createSymlink(Path target,
 Path link,
 boolean createParent)
                   throws IOException,
UnresolvedLinkException

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

Parameters:

target - target.

link - link.

createParent - create parent.

Throws:

IOException - raised on errors performing I/O.

UnresolvedLinkException - unresolved link exception.

getLinkTarget

public Path getLinkTarget(Path f)
                   throws IOException

Partially resolves the path. This is used during symlink resolution in FSLinkResolver, and differs from the similarly named method FileContext.getLinkTarget(Path).

Parameters:

f - the path.

Returns:

target path.

Throws:

IOException - subclass implementations may throw IOException

setPermission

public abstract void setPermission(Path f,
 FsPermission permission)
                            throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

permission - permission.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

setOwner

public abstract void setOwner(Path f,
 String username,
 String groupname)
                       throws AccessControlException,
FileNotFoundException,
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.

Parameters:

f - the path.

username - username.

groupname - groupname.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

setTimes

public abstract void setTimes(Path f,
 long mtime,
 long atime)
                       throws AccessControlException,
FileNotFoundException,
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.

Parameters:

f - the path.

mtime - modify time.

atime - access time.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

getFileChecksum

public abstract FileChecksum getFileChecksum(Path f)
                                      throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

Returns:

File Check sum.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

getFileStatus

public abstract FileStatus getFileStatus(Path f)
                                  throws AccessControlException,
FileNotFoundException,
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.

Parameters:

f - the path.

Returns:

File Status

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

msync

public void msync()
           throws IOException,
UnsupportedOperationException

Synchronize client metadata state.

In some FileSystem implementations such as HDFS metadata synchronization is essential to guarantee consistency of read requests particularly in HA setting.

Throws:

IOException - raised on errors performing I/O.

UnsupportedOperationException - Unsupported Operation Exception.

access

@LimitedPrivate({"HDFS","Hive"})
public void access(Path path,
 FsAction mode)
            throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

path - the path.

mode - fsaction mode.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

getFileLinkStatus

public FileStatus getFileLinkStatus(Path f)
                             throws 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).

Parameters:

f - the path.

Returns:

file status.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnsupportedFileSystemException - UnSupported File System Exception.

IOException - raised on errors performing I/O.

getFileBlockLocations

public abstract BlockLocation[] getFileBlockLocations(Path f,
 long start,
 long len)
                                               throws AccessControlException,
FileNotFoundException,
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.

Parameters:

f - the path.

start - start.

len - length.

Returns:

BlockLocation Array.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

getFsStatus

public FsStatus getFsStatus(Path f)
                     throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

Returns:

Fs Status.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

getFsStatus

public abstract FsStatus getFsStatus()
                              throws AccessControlException,
FileNotFoundException,
IOException

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

Returns:

Fs Status.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

IOException - raised on errors performing I/O.

listStatusIterator

public RemoteIterator<FileStatus> listStatusIterator(Path f)
                                              throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - path.

Returns:

FileStatus Iterator.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

listLocatedStatus

public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
                                                    throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

The specification of this method matches that of FileContext.listLocatedStatus(Path) except that Path f must be for this file system. In HDFS implementation, the BlockLocation of returned LocatedFileStatus will have different formats for replicated and erasure coded file. Please refer to FileSystem.getFileBlockLocations(FileStatus, long, long) for more details.

Parameters:

f - the path.

Returns:

FileStatus Iterator.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

listStatus

public abstract FileStatus[] listStatus(Path f)
                                 throws AccessControlException,
FileNotFoundException,
UnresolvedLinkException,
IOException

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

Parameters:

f - the path.

Returns:

FileStatus Iterator.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

UnresolvedLinkException - unresolved link exception.

IOException - raised on errors performing I/O.

listCorruptFileBlocks

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

Parameters:

path - the path.

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 - raised on errors performing I/O.

setVerifyChecksum

public abstract void setVerifyChecksum(boolean verifyChecksum)
                                throws AccessControlException,
IOException

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

Parameters:

verifyChecksum - verify check sum flag.

Throws:

AccessControlException - access control exception.

IOException - raised on errors performing I/O.

getCanonicalServiceName

public String getCanonicalServiceName()

Get a canonical name for this file system.

Returns:

a URI string that uniquely identifies this file system

getDelegationTokens

@LimitedPrivate({"HDFS","MapReduce"})
public List<Token<?>> getDelegationTokens(String renewer)
                                   throws IOException

Get one or more delegation tokens associated with the filesystem. Normally a file system returns a single delegation token. A file system that manages multiple file systems underneath, could return set of delegation tokens for all the file systems it manages

Parameters:

renewer - the account name that is allowed to renew the token.

Returns:

List of delegation tokens. If delegation tokens not supported then return a list of size zero.

Throws:

IOException - raised on errors performing I/O.

modifyAclEntries

public void modifyAclEntries(Path path,
 List<AclEntry> aclSpec)
                      throws IOException

Modifies ACL entries of files and directories. This method can add new ACL entries or modify the permissions on existing ACL entries. All existing ACL entries that are not specified in this call are retained without changes. (Modifications are merged into the current ACL.)

Parameters:

path - Path to modify

aclSpec - List<AclEntry> describing modifications

Throws:

IOException - if an ACL could not be modified

removeAclEntries

public void removeAclEntries(Path path,
 List<AclEntry> aclSpec)
                      throws IOException

Removes ACL entries from files and directories. Other ACL entries are retained.

Parameters:

path - Path to modify

aclSpec - List<AclEntry> describing entries to remove

Throws:

IOException - if an ACL could not be modified

removeDefaultAcl

public void removeDefaultAcl(Path path)
                      throws IOException

Removes all default ACL entries from files and directories.

Parameters:

path - Path to modify

Throws:

IOException - if an ACL could not be modified

removeAcl

public void removeAcl(Path path)
               throws IOException

Removes all but the base ACL entries of files and directories. The entries for user, group, and others are retained for compatibility with permission bits.

Parameters:

path - Path to modify

Throws:

IOException - if an ACL could not be removed

setAcl

public void setAcl(Path path,
 List<AclEntry> aclSpec)
            throws IOException

Fully replaces ACL of files and directories, discarding all existing entries.

Parameters:

path - Path to modify

aclSpec - List<AclEntry> describing modifications, must include entries for user, group, and others for compatibility with permission bits.

Throws:

IOException - if an ACL could not be modified

getAclStatus

public AclStatus getAclStatus(Path path)
                       throws IOException

Gets the ACLs of files and directories.

Parameters:

path - Path to get

Returns:

RemoteIterator<AclStatus> which returns each AclStatus

Throws:

IOException - if an ACL could not be read

setXAttr

public void setXAttr(Path path,
 String name,
 byte[] value)
              throws IOException

Set an xattr of a file or directory. The name must be prefixed with the namespace followed by ".". For example, "user.attr".

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to modify

name - xattr name.

value - xattr value.

Throws:

IOException - raised on errors performing I/O.

setXAttr

public void setXAttr(Path path,
 String name,
 byte[] value,
 EnumSet<XAttrSetFlag> flag)
              throws IOException

Set an xattr of a file or directory. The name must be prefixed with the namespace followed by ".". For example, "user.attr".

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to modify

name - xattr name.

value - xattr value.

flag - xattr set flag

Throws:

IOException - raised on errors performing I/O.

getXAttr

public byte[] getXAttr(Path path,
 String name)
                throws IOException

Get an xattr for a file or directory. The name must be prefixed with the namespace followed by ".". For example, "user.attr".

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to get extended attribute

name - xattr name.

Returns:

byte[] xattr value.

Throws:

IOException - raised on errors performing I/O.

getXAttrs

public Map<String,byte[]> getXAttrs(Path path)
                             throws IOException

Get all of the xattrs for a file or directory. Only those xattrs for which the logged-in user has permissions to view are returned.

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to get extended attributes

Returns:

Map<String, byte[]> describing the XAttrs of the file or directory

Throws:

IOException - raised on errors performing I/O.

getXAttrs

public Map<String,byte[]> getXAttrs(Path path,
 List<String> names)
                             throws IOException

Get all of the xattrs for a file or directory. Only those xattrs for which the logged-in user has permissions to view are returned.

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to get extended attributes

names - XAttr names.

Returns:

Map<String, byte[]> describing the XAttrs of the file or directory

Throws:

IOException - raised on errors performing I/O.

listXAttrs

public List<String> listXAttrs(Path path)
                        throws IOException

Get all of the xattr names for a file or directory. Only the xattr names for which the logged-in user has permissions to view are returned.

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to get extended attributes

Returns:

Map<String, byte[]> describing the XAttrs of the file or directory

Throws:

IOException - raised on errors performing I/O.

removeXAttr

public void removeXAttr(Path path,
 String name)
                 throws IOException

Remove an xattr of a file or directory. The name must be prefixed with the namespace followed by ".". For example, "user.attr".

Refer to the HDFS extended attributes user documentation for details.

Parameters:

path - Path to remove extended attribute

name - xattr name

Throws:

IOException - raised on errors performing I/O.

createSnapshot

public Path createSnapshot(Path path,
 String snapshotName)
                    throws IOException

The specification of this method matches that of FileContext.createSnapshot(Path, String).

Parameters:

path - the path.

snapshotName - snapshot name.

Returns:

path.

Throws:

IOException - raised on errors performing I/O.

renameSnapshot

public void renameSnapshot(Path path,
 String snapshotOldName,
 String snapshotNewName)
                    throws IOException

The specification of this method matches that of FileContext.renameSnapshot(Path, String, String).

Parameters:

path - the path.

snapshotOldName - snapshot old name.

snapshotNewName - snapshot new name.

Throws:

IOException - raised on errors performing I/O.

deleteSnapshot

public void deleteSnapshot(Path snapshotDir,
 String snapshotName)
                    throws IOException

The specification of this method matches that of FileContext.deleteSnapshot(Path, String).

Parameters:

snapshotDir - snapshot dir.

snapshotName - snapshot name.

Throws:

IOException - raised on errors performing I/O.

satisfyStoragePolicy

public void satisfyStoragePolicy(Path path)
                          throws IOException

Set the source path to satisfy storage policy.

Parameters:

path - The source path referring to either a directory or a file.

Throws:

IOException - raised on errors performing I/O.

setStoragePolicy

public void setStoragePolicy(Path path,
 String policyName)
                      throws IOException

Set the storage policy for a given file or directory.

Parameters:

path - file or directory path.

policyName - the name of the target storage policy. The list of supported Storage policies can be retrieved via getAllStoragePolicies().

Throws:

IOException - raised on errors performing I/O.

unsetStoragePolicy

public void unsetStoragePolicy(Path src)
                        throws IOException

Unset the storage policy set for a given file or directory.

Parameters:

src - file or directory path.

Throws:

IOException - raised on errors performing I/O.

getStoragePolicy

public BlockStoragePolicySpi getStoragePolicy(Path src)
                                       throws IOException

Retrieve the storage policy for a given file or directory.

Parameters:

src - file or directory path.

Returns:

storage policy for give file.

Throws:

IOException - raised on errors performing I/O.

getAllStoragePolicies

public Collection<? extends BlockStoragePolicySpi> getAllStoragePolicies()
                                                                  throws IOException

Retrieve all the storage policies supported by this file system.

Returns:

all storage policies supported by this filesystem.

Throws:

IOException - raised on errors performing I/O.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

openFileWithOptions

public CompletableFuture<FSDataInputStream> openFileWithOptions(Path path,
 OpenFileParameters parameters)
                                                         throws IOException

Open a file with the given set of options. The base implementation performs a blocking call to open(Path, int)in this call; the actual outcome is in the returned CompletableFuture. This avoids having to create some thread pool, while still setting up the expectation that the get() call is needed to evaluate the result.

Parameters:

path - path to the file

parameters - open file parameters from the builder.

Returns:

a future which will evaluate to the opened file.

Throws:

IOException - failure to resolve the link.

IllegalArgumentException - unknown mandatory key

hasPathCapability

public boolean hasPathCapability(Path path,
 String capability)
                          throws IOException

Description copied from interface: PathCapabilities

Probe for a specific capability under the given path. If the function returns true, this instance is explicitly declaring that the capability is available. If the function returns false, it can mean one of:

• The capability is not known.
• The capability is known but it is not supported.
• The capability is known but the filesystem does not know if it is supported under the supplied path.

The core guarantee which a caller can rely on is: if the predicate returns true, then the specific operation/behavior can be expected to be supported. However a specific call may be rejected for permission reasons, the actual file/directory not being present, or some other failure during the attempted execution of the operation.

Implementors: PathCapabilitiesSupport can be used to help implement this method.

Specified by:

hasPathCapability in interface PathCapabilities

Parameters:

path - path to query the capability of.

capability - non-null, non-empty string to query the path for support.

Returns:

true if the capability is supported under that part of the FS.

Throws:

IOException - this should not be raised, except on problems resolving paths or relaying the call.

createMultipartUploader

@Unstable
public MultipartUploaderBuilder createMultipartUploader(Path basePath)
                                                 throws IOException

Create a multipart uploader.

Parameters:

basePath - file path under which all files are uploaded

Returns:

a MultipartUploaderBuilder object to build the uploader

Throws:

IOException - if some early checks cause IO failures.

UnsupportedOperationException - if support is checked early.

getEnclosingRoot

@Public
@Unstable
public Path getEnclosingRoot(Path path)
                      throws IOException

Return path of the enclosing root for a given path The enclosing root path is a common ancestor that should be used for temp and staging dirs as well as within encryption zones and other restricted directories. Call makeQualified on the param path to ensure its part of the correct filesystem

Parameters:

path - file path to find the enclosing root path for

Returns:

a path to the enclosing root

Throws:

IOException - early checks like failure to resolve path cause IO failures

methodNotSupported

protected final void methodNotSupported()

Helper method that throws an UnsupportedOperationException for the current FileSystem method being called.