org.apache.hadoop.fs

Class AbstractFileSystem

java.lang.Object

org.apache.hadoop.fs.AbstractFileSystem

All Implemented Interfaces:

org.apache.hadoop.fs.PathCapabilities

Direct Known Subclasses:

org.apache.hadoop.fs.DelegateToFileSystem, ViewFs

@InterfaceAudience.Public
 @InterfaceStability.Stable
public abstract class AbstractFileSystem
extends Object
implements org.apache.hadoop.fs.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 and Description
protected org.apache.hadoop.fs.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

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, org.apache.hadoop.fs.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, org.apache.hadoop.fs.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.
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,org.apache.hadoop.fs.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.
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.
org.apache.hadoop.fs.FileSystem.Statistics	getStatistics()
protected static org.apache.hadoop.fs.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.
org.apache.hadoop.fs.RemoteIterator<Path>	listCorruptFileBlocks(Path path)
org.apache.hadoop.fs.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.
org.apache.hadoop.fs.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
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.
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.
void	rename(Path src, Path dst, org.apache.hadoop.fs.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 Detail

statistics

protected org.apache.hadoop.fs.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 org.apache.hadoop.fs.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 org.apache.hadoop.fs.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,org.apache.hadoop.fs.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

@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,
                        org.apache.hadoop.fs.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, - AccessControlException, IOException UnresolvedLinkException if symbolic link on path cannot be resolved internally

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

AccessControlException

IOException

create

public final FSDataOutputStream create(Path f,
                                       EnumSet<CreateFlag> createFlag,
                                       org.apache.hadoop.fs.Options.CreateOpts... opts)
                                throws 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:

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,
                                                  org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt,
                                                  boolean createParent)
                                           throws 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:

AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

UnsupportedFileSystemException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

mkdir

public abstract void mkdir(Path dir,
                           FsPermission permission,
                           boolean createParent)
                    throws 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:

AccessControlException

FileAlreadyExistsException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

delete

public abstract boolean delete(Path f,
                               boolean recursive)
                        throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

open

public FSDataInputStream open(Path f)
                       throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

open

public abstract FSDataInputStream open(Path f,
                                       int bufferSize)
                                throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

truncate

public boolean truncate(Path f,
                        long newLength)
                 throws AccessControlException,
                        FileNotFoundException,
                        org.apache.hadoop.fs.UnresolvedLinkException,
                        IOException

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

Throws:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setReplication

public abstract boolean setReplication(Path f,
                                       short replication)
                                throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

rename

public final void rename(Path src,
                         Path dst,
                         org.apache.hadoop.fs.Options.Rename... options)
                  throws 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:

AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

renameInternal

public abstract void renameInternal(Path src,
                                    Path dst)
                             throws 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:

AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

renameInternal

public void renameInternal(Path src,
                           Path dst,
                           boolean overwrite)
                    throws 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:

AccessControlException

FileAlreadyExistsException

FileNotFoundException

ParentNotDirectoryException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

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,
                          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

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

Throws:

IOException - subclass implementations may throw IOException

setPermission

public abstract void setPermission(Path f,
                                   FsPermission permission)
                            throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setOwner

public abstract void setOwner(Path f,
                              String username,
                              String groupname)
                       throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

setTimes

public abstract void setTimes(Path f,
                              long mtime,
                              long atime)
                       throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFileChecksum

public abstract FileChecksum getFileChecksum(Path f)
                                      throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFileStatus

public abstract FileStatus getFileStatus(Path f)
                                  throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

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

UnsupportedOperationException

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).

Throws:

AccessControlException

FileNotFoundException

UnsupportedFileSystemException

IOException

getFileBlockLocations

public abstract BlockLocation[] getFileBlockLocations(Path f,
                                                      long start,
                                                      long len)
                                               throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFsStatus

public FsStatus getFsStatus(Path f)
                     throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

getFsStatus

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

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

Throws:

AccessControlException

FileNotFoundException

IOException

listStatusIterator

public org.apache.hadoop.fs.RemoteIterator<FileStatus> listStatusIterator(Path f)
                                                                   throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listLocatedStatus

public org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
                                                                         throws 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. 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.

Throws:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listStatus

public abstract FileStatus[] listStatus(Path f)
                                 throws 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:

AccessControlException

FileNotFoundException

org.apache.hadoop.fs.UnresolvedLinkException

IOException

listCorruptFileBlocks

public org.apache.hadoop.fs.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 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:

AccessControlException

IOException

getCanonicalServiceName

public String getCanonicalServiceName()

Get a canonical name for this file system.

Returns:

a URI string that uniquely identifies this file system

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 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 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 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 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

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

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

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 describing the XAttrs of the file or directory

Throws:

IOException

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 describing the XAttrs of the file or directory

Throws:

IOException

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 describing the XAttrs of the file or directory

Throws:

IOException

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

createSnapshot

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

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

Throws:

IOException

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).

Throws:

IOException

deleteSnapshot

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

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

Throws:

IOException

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

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

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

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

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

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hasPathCapability

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

Description copied from interface: org.apache.hadoop.fs.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 org.apache.hadoop.fs.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.