AbstractFileSystem (Apache Hadoop Main 2.8.3 API)

java.lang.Object
- org.apache.hadoop.fs.AbstractFileSystem

Direct Known Subclasses:

org.apache.hadoop.fs.DelegateToFileSystem, ViewFs
```
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class AbstractFileSystem
extends Object
```
This class provides an interface for implementors of a Hadoop file system (analogous to the VFS of Unix). Applications do not access this class; instead they access files across all file systems using FileContext. Pathnames passed to AbstractFileSystem can be fully qualified URI that matches the "this" file system (ie same scheme and authority) or a Slash-relative name that is assumed to be relative to the root of the "this" file system .

Field Summary

Fields
Modifier and Type Field and Description

protected org.apache.hadoop.fs.FileSystem.Statistics statistics
The statistics for this file system.

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

Methods
Modifier and Type	Method and Description
`void`	`checkPath(Path path)` Check that a Path belongs to this FileSystem.
`void`	`checkScheme(URI uri, String supportedScheme)` Check that the Uri's scheme matches
`static void`	`clearStatistics()`
`FSDataOutputStream`	`create(Path f, EnumSet<CreateFlag> createFlag, 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`	`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.
`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`	`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

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.

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

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

Class AbstractFileSystem

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

statistics

Constructor Detail

AbstractFileSystem

Method Detail

getStatistics

isValidName

createFileSystem

getStatistics

clearStatistics

printStatistics

getAllStatistics

get

checkScheme

getUriDefaultPort

getUri

checkPath

getUriPath

makeQualified

getInitialWorkingDirectory

getHomeDirectory

getServerDefaults

getServerDefaults

resolvePath

create

createInternal

mkdir

delete

open

open

truncate

setReplication

rename

renameInternal

renameInternal

supportsSymlinks

createSymlink

getLinkTarget

setPermission

setOwner

setTimes

getFileChecksum

getFileStatus

getFileLinkStatus

getFileBlockLocations

getFsStatus

getFsStatus

listStatusIterator

listLocatedStatus

listStatus

listCorruptFileBlocks

setVerifyChecksum

getCanonicalServiceName

modifyAclEntries

removeAclEntries

removeDefaultAcl

removeAcl

setAcl

getAclStatus

setXAttr

setXAttr

getXAttr

getXAttrs

getXAttrs

listXAttrs

removeXAttr

createSnapshot

renameSnapshot

deleteSnapshot

setStoragePolicy

unsetStoragePolicy

getStoragePolicy

getAllStoragePolicies

hashCode

equals