Package org.apache.hadoop.fs

Class FileContext.Util

java.lang.Object

org.apache.hadoop.fs.FileContext.Util

Enclosing class:

FileContext

public class FileContext.Util
extends Object

Utility/library methods built over the basic FileContext methods. Since this are library functions, the oprtation are not atomic and some of them may partially complete if other threads are making changes to the same part of the name space.

Constructor Summary

Constructors

Constructor	Description
Util()

Method Summary

Modifier and Type	Method	Description
boolean	copy(Path src, Path dst)	Copy file from src to dest.
boolean	copy(Path src, Path dst, boolean deleteSource, boolean overwrite)	Copy from src to dst, optionally deleting src and overwriting dst.
boolean	exists(Path f)	Does the file exist?
ContentSummary	getContentSummary(Path f)	Return the ContentSummary of path f.
FileStatus[]	globStatus(Path pathPattern)	Return all the files that match filePattern and are not checksum files.
FileStatus[]	globStatus(Path pathPattern, PathFilter filter)	Return an array of FileStatus objects whose path names match pathPattern and is accepted by the user-supplied path filter.
RemoteIterator<LocatedFileStatus>	listFiles(Path f, boolean recursive)	List the statuses and block locations of the files in the given path.
FileStatus[]	listStatus(Path f)	List the statuses of the files/directories in the given path if the path is a directory.
FileStatus[]	listStatus(Path[] files)	See listStatus(Path[], PathFilter)
FileStatus[]	listStatus(Path[] files, PathFilter filter)	Filter files/directories in the given list of paths using user-supplied path filter.
FileStatus[]	listStatus(Path f, PathFilter filter)	Filter files/directories in the given path using the user-supplied path filter.

Methods inherited from class java.lang.Object

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

Constructor Details

Util

public Util()

Method Details

exists

public boolean exists(Path f)
               throws AccessControlException,
UnsupportedFileSystemException,
IOException

Does the file exist? Note: Avoid using this method if you already have FileStatus in hand. Instead reuse the FileStatus

Parameters:

f - the file or dir to be checked

Returns:

if f exists true, not false.

Throws:

AccessControlException - If access is denied

IOException - If an I/O error occurred

UnsupportedFileSystemException - If file system for f is not supported Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

getContentSummary

public ContentSummary getContentSummary(Path f)
                                 throws AccessControlException,
FileNotFoundException,
UnsupportedFileSystemException,
IOException

Return the ContentSummary of path f.

Parameters:

f - path

Returns:

the ContentSummary of path f.

Throws:

AccessControlException - If access is denied

FileNotFoundException - If f does not exist

UnsupportedFileSystemException - If file system for f is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

listStatus

public FileStatus[] listStatus(Path[] files)
                        throws AccessControlException,
FileNotFoundException,
IOException

See listStatus(Path[], PathFilter)

Parameters:

files - files.

Returns:

file status array.

Throws:

AccessControlException - If access is denied.

FileNotFoundException - If files does not exist.

IOException - If an I/O error occurred.

listStatus

public FileStatus[] listStatus(Path f,
 PathFilter filter)
                        throws AccessControlException,
FileNotFoundException,
UnsupportedFileSystemException,
IOException

Filter files/directories in the given path using the user-supplied path filter.

Parameters:

f - is the path name

filter - is the user-supplied path filter

Returns:

an array of FileStatus objects for the files under the given path after applying the filter

Throws:

AccessControlException - If access is denied

FileNotFoundException - If f does not exist

UnsupportedFileSystemException - If file system for pathPattern is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

listStatus

public FileStatus[] listStatus(Path[] files,
 PathFilter filter)
                        throws AccessControlException,
FileNotFoundException,
IOException

Filter files/directories in the given list of paths using user-supplied path filter.

Parameters:

files - is a list of paths

filter - is the filter

Returns:

a list of statuses for the files under the given paths after applying the filter

Throws:

AccessControlException - If access is denied

FileNotFoundException - If a file in files does not exist

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

listStatus

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

List the statuses of the files/directories in the given path if the path is a directory.

Parameters:

f - is the path

Returns:

an array that contains statuses of the files/directories in the given path

Throws:

AccessControlException - If access is denied

FileNotFoundException - If f does not exist

UnsupportedFileSystemException - If file system for f is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

listFiles

public RemoteIterator<LocatedFileStatus> listFiles(Path f,
 boolean recursive)
                                            throws AccessControlException,
FileNotFoundException,
UnsupportedFileSystemException,
IOException

List the statuses and block locations of the files in the given path. If the path is a directory, if recursive is false, returns files in the directory; if recursive is true, return files in the subtree rooted at the path. The subtree is traversed in the depth-first order. If the path is a file, return the file's status and block locations. Files across symbolic links are also returned.

Parameters:

f - is the path

recursive - if the subdirectories need to be traversed recursively

Returns:

an iterator that traverses statuses of the files If any IO exception (for example a sub-directory gets deleted while listing is being executed), next() or hasNext() of the returned iterator may throw a RuntimeException with the IO exception as the cause.

Throws:

AccessControlException - If access is denied

FileNotFoundException - If f does not exist

UnsupportedFileSystemException - If file system for f is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

globStatus

public FileStatus[] globStatus(Path pathPattern)
                        throws AccessControlException,
UnsupportedFileSystemException,
IOException

Return all the files that match filePattern and are not checksum files. Results are sorted by their names.

A filename pattern is composed of regular characters and special pattern matching characters, which are:

?

Matches any single character.

*

Matches zero or more characters.

[abc]

Matches a single character from character set {a,b,c}.

[a-b]

Matches a single character from the character range {a...b}. Note: character a must be lexicographically less than or equal to character b.

[^a]

Matches a single char that is not from character set or range {a}. Note that the ^ character must occur immediately to the right of the opening bracket.

\c

Removes (escapes) any special meaning of character c.

{ab,cd}

Matches a string from the string set {ab, cd}

{ab,c{de,fh}}

Matches a string from string set {ab, cde, cfh}

Parameters:

pathPattern - a glob specifying a path pattern

Returns:

an array of paths that match the path pattern

Throws:

AccessControlException - If access is denied

UnsupportedFileSystemException - If file system for pathPattern is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

globStatus

public FileStatus[] globStatus(Path pathPattern,
 PathFilter filter)
                        throws AccessControlException,
UnsupportedFileSystemException,
IOException

Return an array of FileStatus objects whose path names match pathPattern and is accepted by the user-supplied path filter. Results are sorted by their path names. Return null if pathPattern has no glob and the path does not exist. Return an empty array if pathPattern has a glob and no path matches it.

Parameters:

pathPattern - glob specifying the path pattern

filter - user-supplied path filter

Returns:

an array of FileStatus objects

Throws:

AccessControlException - If access is denied

UnsupportedFileSystemException - If file system for pathPattern is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server

copy

public boolean copy(Path src,
 Path dst)
             throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
UnsupportedFileSystemException,
IOException

Copy file from src to dest. See copy(Path, Path, boolean, boolean)

Parameters:

src - src.

dst - dst.

Returns:

if success copy true, not false.

Throws:

AccessControlException - If access is denied.

FileAlreadyExistsException - If file src already exists.

FileNotFoundException - if next file does not exist any more.

ParentNotDirectoryException - If parent of src is not a directory.

UnsupportedFileSystemException - If file system for src/dst is not supported.

IOException - If an I/O error occurred.

copy

public boolean copy(Path src,
 Path dst,
 boolean deleteSource,
 boolean overwrite)
             throws AccessControlException,
FileAlreadyExistsException,
FileNotFoundException,
ParentNotDirectoryException,
UnsupportedFileSystemException,
IOException

Copy from src to dst, optionally deleting src and overwriting dst.

Parameters:

src - src.

dst - dst.

deleteSource - - delete src if true

overwrite - overwrite dst if true; throw IOException if dst exists and overwrite is false.

Returns:

true if copy is successful

Throws:

AccessControlException - If access is denied

FileAlreadyExistsException - If dst already exists

FileNotFoundException - If src does not exist

ParentNotDirectoryException - If parent of dst is not a directory

UnsupportedFileSystemException - If file system for src or dst is not supported

IOException - If an I/O error occurred Exceptions applicable to file systems accessed over RPC:

RpcClientException - If an exception occurred in the RPC client

RpcServerException - If an exception occurred in the RPC server

UnexpectedServerException - If server implementation throws undeclared exception to RPC server RuntimeExceptions:

InvalidPathException - If path dst is invalid