Package org.apache.hadoop.fs

Class DelegateToFileSystem

java.lang.Object

org.apache.hadoop.fs.AbstractFileSystem

org.apache.hadoop.fs.DelegateToFileSystem

All Implemented Interfaces:

PathCapabilities

Direct Known Subclasses:

FtpFs, HarFs, RawLocalFs

@Private
@Unstable
public abstract class DelegateToFileSystem
extends AbstractFileSystem

Implementation of AbstractFileSystem based on the existing implementation of FileSystem.

Field Summary

Fields

Modifier and Type	Field	Description
protected final FileSystem	fsImpl

Fields inherited from class org.apache.hadoop.fs.AbstractFileSystem

statistics

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DelegateToFileSystem(URI theUri, FileSystem theFsImpl, Configuration conf, String supportedScheme, boolean authorityRequired)

Method Summary

Modifier and Type	Method	Description
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 AbstractFileSystem.create(Path, EnumSet, Options.CreateOpts...) except that the opts have been declared explicitly.
void	createSymlink(Path target, Path link, boolean createParent)	The specification of this method matches that of FileContext.createSymlink(Path, Path, boolean);
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.
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.
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.
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.
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.
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.
FsServerDefaults	getServerDefaults()	Deprecated.
FsServerDefaults	getServerDefaults(Path f)	Return a set of server default configuration values based on path.
int	getUriDefaultPort()	The default port of this file system.
boolean	hasPathCapability(Path path, String capability)	Probe for a specific capability under the given path.
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.
void	mkdir(Path dir, FsPermission permission, boolean createParent)	The specification of this method matches that of FileContext.mkdir(Path, FsPermission, boolean) except that the Path f must be fully qualified and the permission is absolute (i.e.
FSDataInputStream	open(Path f, 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 by delegating to FileSystem.openFileWithOptions(Path, org.apache.hadoop.fs.impl.OpenFileParameters).
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	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.
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.
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	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.
void	setVerifyChecksum(boolean verifyChecksum)	The specification of this method matches that of FileContext.setVerifyChecksum(boolean, Path) except that Path f must be for this file system.
boolean	supportsSymlinks()	Returns true if the file system supports symlinks, false otherwise.
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.

Methods inherited from class org.apache.hadoop.fs.AbstractFileSystem

access, checkPath, checkScheme, clearStatistics, create, createFileSystem, createMultipartUploader, createSnapshot, deleteSnapshot, equals, get, getAclStatus, getAllStatistics, getAllStoragePolicies, getEnclosingRoot, getStatistics, getStatistics, getStoragePolicy, getUri, getUriPath, getXAttr, getXAttrs, getXAttrs, hashCode, isValidName, listCorruptFileBlocks, listLocatedStatus, listStatusIterator, listXAttrs, makeQualified, methodNotSupported, modifyAclEntries, msync, open, printStatistics, removeAcl, removeAclEntries, removeDefaultAcl, removeXAttr, rename, renameInternal, renameSnapshot, resolvePath, satisfyStoragePolicy, setAcl, setStoragePolicy, setXAttr, setXAttr, unsetStoragePolicy

Methods inherited from class java.lang.Object

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

Field Details

fsImpl

protected final FileSystem fsImpl

Constructor Details

DelegateToFileSystem

protected DelegateToFileSystem(URI theUri,
 FileSystem theFsImpl,
 Configuration conf,
 String supportedScheme,
 boolean authorityRequired)
                        throws IOException,
URISyntaxException

Throws:

IOException

URISyntaxException

Method Details

getInitialWorkingDirectory

public Path getInitialWorkingDirectory()

Description copied from class: AbstractFileSystem

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.

Overrides:

getInitialWorkingDirectory in class AbstractFileSystem

Returns:

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

createInternal

public FSDataOutputStream createInternal(Path f,
 EnumSet<CreateFlag> flag,
 FsPermission absolutePermission,
 int bufferSize,
 short replication,
 long blockSize,
 Progressable progress,
 Options.ChecksumOpt checksumOpt,
 boolean createParent)
                                  throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

createInternal in class AbstractFileSystem

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.

delete

public boolean delete(Path f,
 boolean recursive)
               throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

delete in class AbstractFileSystem

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.

getFileBlockLocations

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

Description copied from class: AbstractFileSystem

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

Specified by:

getFileBlockLocations in class AbstractFileSystem

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.

getFileChecksum

public FileChecksum getFileChecksum(Path f)
                             throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

getFileChecksum in class AbstractFileSystem

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 FileStatus getFileStatus(Path f)
                         throws IOException

Description copied from class: AbstractFileSystem

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.

Specified by:

getFileStatus in class AbstractFileSystem

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.

getFileLinkStatus

public FileStatus getFileLinkStatus(Path f)
                             throws IOException

Description copied from class: AbstractFileSystem

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 AbstractFileSystem.getFileStatus(Path).

Overrides:

getFileLinkStatus in class AbstractFileSystem

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.

getFsStatus

public FsStatus getFsStatus()
                     throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

getFsStatus in class AbstractFileSystem

Returns:

Fs Status.

Throws:

AccessControlException - access control exception.

FileNotFoundException - file not found exception.

IOException - raised on errors performing I/O.

getFsStatus

public FsStatus getFsStatus(Path f)
                     throws IOException

Description copied from class: AbstractFileSystem

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

Overrides:

getFsStatus in class AbstractFileSystem

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.

getServerDefaults

@Deprecated
public FsServerDefaults getServerDefaults()
                                   throws IOException

Deprecated.

Description copied from class: AbstractFileSystem

Return a set of server default configuration values.

Specified by:

getServerDefaults in class AbstractFileSystem

Returns:

server default configuration values

Throws:

IOException - an I/O error occurred

getServerDefaults

public FsServerDefaults getServerDefaults(Path f)
                                   throws IOException

Description copied from class: AbstractFileSystem

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

Overrides:

getServerDefaults in class AbstractFileSystem

Parameters:

f - path to fetch server defaults

Returns:

server default configuration values for path

Throws:

IOException - an I/O error occurred

getHomeDirectory

public Path getHomeDirectory()

Description copied from class: AbstractFileSystem

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

Overrides:

getHomeDirectory in class AbstractFileSystem

Returns:

current user's home directory.

getUriDefaultPort

public int getUriDefaultPort()

Description copied from class: AbstractFileSystem

The default port of this file system.

Specified by:

getUriDefaultPort in class AbstractFileSystem

Returns:

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

listStatus

public FileStatus[] listStatus(Path f)
                        throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

listStatus in class AbstractFileSystem

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.

mkdir

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

Description copied from class: AbstractFileSystem

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).

Specified by:

mkdir in class AbstractFileSystem

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.

open

public FSDataInputStream open(Path f,
 int bufferSize)
                       throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

open in class AbstractFileSystem

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 IOException

Description copied from class: AbstractFileSystem

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

Overrides:

truncate in class AbstractFileSystem

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.

renameInternal

public void renameInternal(Path src,
 Path dst)
                    throws IOException

Description copied from class: AbstractFileSystem

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 AbstractFileSystem.renameInternal(Path, Path, boolean)

Specified by:

renameInternal in class AbstractFileSystem

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.

setOwner

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

Description copied from class: AbstractFileSystem

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

Specified by:

setOwner in class AbstractFileSystem

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.

setPermission

public void setPermission(Path f,
 FsPermission permission)
                   throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

setPermission in class AbstractFileSystem

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.

setReplication

public boolean setReplication(Path f,
 short replication)
                       throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

setReplication in class AbstractFileSystem

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.

setTimes

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

Description copied from class: AbstractFileSystem

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

Specified by:

setTimes in class AbstractFileSystem

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.

setVerifyChecksum

public void setVerifyChecksum(boolean verifyChecksum)
                       throws IOException

Description copied from class: AbstractFileSystem

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

Specified by:

setVerifyChecksum in class AbstractFileSystem

Parameters:

verifyChecksum - verify check sum flag.

Throws:

AccessControlException - access control exception.

IOException - raised on errors performing I/O.

supportsSymlinks

public boolean supportsSymlinks()

Description copied from class: AbstractFileSystem

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

Overrides:

supportsSymlinks in class AbstractFileSystem

Returns:

true if filesystem supports symlinks

createSymlink

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

Description copied from class: AbstractFileSystem

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

Overrides:

createSymlink in class AbstractFileSystem

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

Description copied from class: AbstractFileSystem

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

Overrides:

getLinkTarget in class AbstractFileSystem

Parameters:

f - the path.

Returns:

target path.

Throws:

IOException - subclass implementations may throw IOException

getCanonicalServiceName

public String getCanonicalServiceName()

Description copied from class: AbstractFileSystem

Get a canonical name for this file system.

Overrides:

getCanonicalServiceName in class AbstractFileSystem

Returns:

a URI string that uniquely identifies this file system

getDelegationTokens

public List<Token<?>> getDelegationTokens(String renewer)
                                   throws IOException

Description copied from class: AbstractFileSystem

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

Overrides:

getDelegationTokens in class AbstractFileSystem

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.

openFileWithOptions

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

Open a file by delegating to FileSystem.openFileWithOptions(Path, org.apache.hadoop.fs.impl.OpenFileParameters).

Overrides:

openFileWithOptions in class AbstractFileSystem

Parameters:

path - path to the file

parameters - open file parameters from the builder.

Returns:

a future which will evaluate to the opened file.ControlAlpha

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

Overrides:

hasPathCapability in class AbstractFileSystem

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.