FileSystem (Apache Hadoop Main 3.2.3 API)

java.lang.Object
- org.apache.hadoop.conf.Configured
- - org.apache.hadoop.fs.FileSystem

All Implemented Interfaces:

Closeable, AutoCloseable, Configurable, org.apache.hadoop.fs.PathCapabilities, org.apache.hadoop.security.token.DelegationTokenIssuer

Direct Known Subclasses:

AdlFileSystem, FilterFileSystem, FTPFileSystem, NativeAzureFileSystem, NativeS3FileSystem, RawLocalFileSystem, ViewFileSystem
```
@InterfaceAudience.Public
 @InterfaceStability.Stable
public abstract class FileSystem
extends Configured
implements Closeable, org.apache.hadoop.security.token.DelegationTokenIssuer, org.apache.hadoop.fs.PathCapabilities
```
An abstract base class for a fairly generic filesystem. It may be implemented as a distributed filesystem, or as a "local" one that reflects the locally-connected disk. The local version exists for small Hadoop instances and for testing.
All user code that may potentially use the Hadoop Distributed File System should be written to use a FileSystem object or its successor, FileContext.
The local implementation is LocalFileSystem and distributed implementation is DistributedFileSystem. There are other implementations for object stores and (outside the Apache Hadoop codebase), third party filesystems.
Notes
1. The behaviour of the filesystem is specified in the Hadoop documentation. However, the normative specification of the behavior of this class is actually HDFS: if HDFS does not behave the way these Javadocs or the specification in the Hadoop documentations define, assume that the documentation is incorrect.
2. The term FileSystem refers to an instance of this class.
3. The acronym "FS" is used as an abbreviation of FileSystem.
4. The term filesystem refers to the distributed/local filesystem itself, rather than the class used to interact with it.
5. The term "file" refers to a file in the remote filesystem, rather than instances of java.io.File.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`DEFAULT_FS`
`static String`	`FS_DEFAULT_NAME_KEY`
`static int`	`SHUTDOWN_HOOK_PRIORITY` Priority of the FileSystem shutdown hook: 10.
`protected org.apache.hadoop.fs.FileSystem.Statistics`	`statistics` The statistics for this file system.
`static String`	`TRASH_PREFIX` Prefix for trash directory: ".Trash".
`static String`	`USER_HOME_PREFIX`

Constructor Summary

Constructors
Modifier Constructor and Description

protected FileSystem()

Constructors
Modifier	Constructor and Description
`protected`	`FileSystem()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`FSDataOutputStream`	`append(Path f)` Append to an existing file (optional operation).
`FSDataOutputStream`	`append(Path f, int bufferSize)` Append to an existing file (optional operation).
`abstract FSDataOutputStream`	`append(Path f, int bufferSize, Progressable progress)` Append to an existing file (optional operation).
`FSDataOutputStreamBuilder`	`appendFile(Path path)` Create a Builder to append a file.
`static boolean`	`areSymlinksEnabled()`
`boolean`	`cancelDeleteOnExit(Path f)` Cancel the scheduled deletion of the path when the FileSystem is closed.
`protected URI`	`canonicalizeUri(URI uri)` Canonicalize the given URI.
`protected void`	`checkPath(Path path)` Check that a Path belongs to this FileSystem.
`static void`	`clearStatistics()` Reset all statistics for all file systems.
`void`	`close()` Close this FileSystem instance.
`static void`	`closeAll()` Close all cached FileSystem instances.
`static void`	`closeAllForUGI(UserGroupInformation ugi)` Close all cached FileSystem instances for a given UGI.
`void`	`completeLocalOutput(Path fsOutputFile, Path tmpLocalFile)` Called when we're all done writing to the target.
`void`	`concat(Path trg, Path[] psrcs)` Concat existing files together.
`void`	`copyFromLocalFile(boolean delSrc, boolean overwrite, Path[] srcs, Path dst)` The src files are on the local disk.
`void`	`copyFromLocalFile(boolean delSrc, boolean overwrite, Path src, Path dst)` The src file is on the local disk.
`void`	`copyFromLocalFile(boolean delSrc, Path src, Path dst)` The src file is on the local disk.
`void`	`copyFromLocalFile(Path src, Path dst)` The src file is on the local disk.
`void`	`copyToLocalFile(boolean delSrc, Path src, Path dst)` Copy it a file from a remote filesystem to the local one.
`void`	`copyToLocalFile(boolean delSrc, Path src, Path dst, boolean useRawLocalFileSystem)` The src file is under this filesystem, and the dst is on the local disk.
`void`	`copyToLocalFile(Path src, Path dst)` Copy it a file from the remote filesystem to the local one.
`static FSDataOutputStream`	`create(FileSystem fs, Path file, FsPermission permission)` Create a file with the provided permission.
`FSDataOutputStream`	`create(Path f)` Create an FSDataOutputStream at the indicated Path.
`FSDataOutputStream`	`create(Path f, boolean overwrite)` Create an FSDataOutputStream at the indicated Path.
`FSDataOutputStream`	`create(Path f, boolean overwrite, int bufferSize)` Create an FSDataOutputStream at the indicated Path.
`FSDataOutputStream`	`create(Path f, boolean overwrite, int bufferSize, Progressable progress)` Create an `FSDataOutputStream` at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize)` Create an FSDataOutputStream at the indicated Path.
`FSDataOutputStream`	`create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`abstract FSDataOutputStream`	`create(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`create(Path f, FsPermission permission, EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`create(Path f, FsPermission permission, EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize, Progressable progress, org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt)` Create an FSDataOutputStream at the indicated Path with a custom checksum option.
`FSDataOutputStream`	`create(Path f, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`create(Path f, short replication)` Create an FSDataOutputStream at the indicated Path.
`FSDataOutputStream`	`create(Path f, short replication, Progressable progress)` Create an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStreamBuilder`	`createFile(Path path)` Create a new FSDataOutputStreamBuilder for the file with path.
`boolean`	`createNewFile(Path f)` Creates the given Path as a brand-new zero-length file.
`FSDataOutputStream`	`createNonRecursive(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`createNonRecursive(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`FSDataOutputStream`	`createNonRecursive(Path f, FsPermission permission, EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize, Progressable progress)` Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
`protected PathHandle`	`createPathHandle(FileStatus stat, org.apache.hadoop.fs.Options.HandleOpt... opt)` Hook to implement support for `PathHandle` operations.
`Path`	`createSnapshot(Path path)` Create a snapshot with a default name.
`Path`	`createSnapshot(Path path, String snapshotName)` Create a snapshot.
`void`	`createSymlink(Path target, Path link, boolean createParent)` See `FileContext.createSymlink(Path, Path, boolean)`.
`boolean`	`delete(Path f)` Deprecated. Use `delete(Path, boolean)` instead.
`abstract boolean`	`delete(Path f, boolean recursive)` Delete a file.
`boolean`	`deleteOnExit(Path f)` Mark a path to be deleted when its FileSystem is closed.
`void`	`deleteSnapshot(Path path, String snapshotName)` Delete a snapshot of a directory.
`static void`	`enableSymlinks()`
`boolean`	`exists(Path f)` Check if a path exists.
`protected Path`	`fixRelativePart(Path p)` See `FileContext.fixRelativePart(org.apache.hadoop.fs.Path)`.
`static FileSystem`	`get(Configuration conf)` Returns the configured FileSystem implementation.
`static FileSystem`	`get(URI uri, Configuration conf)` Get a FileSystem for this URI's scheme and authority.
`static FileSystem`	`get(URI uri, Configuration conf, String user)` Get a FileSystem instance based on the uri, the passed in configuration and the user.
`AclStatus`	`getAclStatus(Path path)` Gets the ACL of a file or directory.
`static List<org.apache.hadoop.fs.FileSystem.Statistics>`	`getAllStatistics()` Deprecated. use `getGlobalStorageStatistics()`
`Collection<? extends BlockStoragePolicySpi>`	`getAllStoragePolicies()` Retrieve all the storage policies supported by this file system.
`long`	`getBlockSize(Path f)` Deprecated. Use `getFileStatus(Path)` instead
`String`	`getCanonicalServiceName()` Get a canonical service name for this FileSystem.
`protected URI`	`getCanonicalUri()` Return a canonicalized form of this FileSystem's URI.
`ContentSummary`	`getContentSummary(Path f)` Return the `ContentSummary` of a given `Path`.
`long`	`getDefaultBlockSize()` Deprecated. use `getDefaultBlockSize(Path)` instead
`long`	`getDefaultBlockSize(Path f)` Return the number of bytes that large input files should be optimally be split into to minimize I/O time.
`protected int`	`getDefaultPort()` Get the default port for this FileSystem.
`short`	`getDefaultReplication()` Deprecated. use `getDefaultReplication(Path)` instead
`short`	`getDefaultReplication(Path path)` Get the default replication for a path.
`static URI`	`getDefaultUri(Configuration conf)` Get the default FileSystem URI from a configuration.
`BlockLocation[]`	`getFileBlockLocations(FileStatus file, long start, long len)` Return an array containing hostnames, offset and size of portions of the given file.
`BlockLocation[]`	`getFileBlockLocations(Path p, long start, long len)` Return an array containing hostnames, offset and size of portions of the given file.
`FileChecksum`	`getFileChecksum(Path f)` Get the checksum of a file, if the FS supports checksums.
`FileChecksum`	`getFileChecksum(Path f, long length)` Get the checksum of a file, from the beginning of the file till the specific length.
`FileStatus`	`getFileLinkStatus(Path f)` See `FileContext.getFileLinkStatus(Path)`.
`abstract FileStatus`	`getFileStatus(Path f)` Return a file status object that represents the path.
`static Class<? extends FileSystem>`	`getFileSystemClass(String scheme, Configuration conf)` Get the FileSystem implementation class of a filesystem.
`protected static FileSystem`	`getFSofPath(Path absOrFqPath, Configuration conf)`
`static GlobalStorageStatistics`	`getGlobalStorageStatistics()` Get the global storage statistics.
`Path`	`getHomeDirectory()` Return the current user's home directory in this FileSystem.
`protected Path`	`getInitialWorkingDirectory()` Note: with the new FileContext class, getWorkingDirectory() will be removed.
`long`	`getLength(Path f)` Deprecated. Use `getFileStatus(Path)` instead.
`Path`	`getLinkTarget(Path f)` See `FileContext.getLinkTarget(Path)`.
`static LocalFileSystem`	`getLocal(Configuration conf)` Get the local FileSystem.
`String`	`getName()` Deprecated. call `getUri()` instead.
`static FileSystem`	`getNamed(String name, Configuration conf)` Deprecated. call `get(URI, Configuration)` instead.
`PathHandle`	`getPathHandle(FileStatus stat, org.apache.hadoop.fs.Options.HandleOpt... opt)` Create a durable, serializable handle to the referent of the given entity.
`QuotaUsage`	`getQuotaUsage(Path f)` Return the `QuotaUsage` of a given `Path`.
`short`	`getReplication(Path src)` Deprecated. Use `getFileStatus(Path)` instead
`String`	`getScheme()` Return the protocol scheme for this FileSystem.
`FsServerDefaults`	`getServerDefaults()` Deprecated. use `getServerDefaults(Path)` instead
`FsServerDefaults`	`getServerDefaults(Path p)` Return a set of server default configuration values.
`static Map<String,org.apache.hadoop.fs.FileSystem.Statistics>`	`getStatistics()` Deprecated. use `getGlobalStorageStatistics()`
`static org.apache.hadoop.fs.FileSystem.Statistics`	`getStatistics(String scheme, Class<? extends FileSystem> cls)` Deprecated. use `getGlobalStorageStatistics()`
`FsStatus`	`getStatus()` Returns a status object describing the use and capacity of the filesystem.
`FsStatus`	`getStatus(Path p)` Returns a status object describing the use and capacity of the filesystem.
`BlockStoragePolicySpi`	`getStoragePolicy(Path src)` Query the effective storage policy ID for the given file or directory.
`StorageStatistics`	`getStorageStatistics()` Get the StorageStatistics for this FileSystem object.
`Path`	`getTrashRoot(Path path)` Get the root directory of Trash for current user when the path specified is deleted.
`Collection<FileStatus>`	`getTrashRoots(boolean allUsers)` Get all the trash roots for current user or all users.
`abstract URI`	`getUri()` Returns a URI which identifies this FileSystem.
`long`	`getUsed()` Return the total size of all files in the filesystem.
`long`	`getUsed(Path path)` Return the total size of all files from a specified path.
`abstract Path`	`getWorkingDirectory()` Get the current working directory for the given FileSystem
`byte[]`	`getXAttr(Path path, String name)` Get an xattr name and value for a file or directory.
`Map<String,byte[]>`	`getXAttrs(Path path)` Get all of the xattr name/value pairs for a file or directory.
`Map<String,byte[]>`	`getXAttrs(Path path, List<String> names)` Get all of the xattrs name/value pairs for a file or directory.
`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.
`boolean`	`hasPathCapability(Path path, String capability)` The base FileSystem implementation generally has no knowledge of the capabilities of actual implementations.
`void`	`initialize(URI name, Configuration conf)` Initialize a FileSystem.
`boolean`	`isDirectory(Path f)` Deprecated. Use `getFileStatus(Path)` instead
`boolean`	`isFile(Path f)` Deprecated. Use `getFileStatus(Path)` instead
`org.apache.hadoop.fs.RemoteIterator<Path>`	`listCorruptFileBlocks(Path path)` List corrupted file blocks.
`org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus>`	`listFiles(Path f, boolean recursive)` List the statuses and block locations of the files in the given path.
`org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus>`	`listLocatedStatus(Path f)` List the statuses of the files/directories in the given path if the path is a directory.
`protected org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus>`	`listLocatedStatus(Path f, PathFilter filter)` List a directory.
`abstract 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)` Filter files/directories in the given list of paths using default path filter.
`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.
`org.apache.hadoop.fs.RemoteIterator<FileStatus>`	`listStatusIterator(Path p)` Returns a remote iterator so that followup calls are made on demand while consuming the entries.
`List<String>`	`listXAttrs(Path path)` Get all of the xattr names for a file or directory.
`Path`	`makeQualified(Path path)` Qualify a path to one which uses this FileSystem and, if relative, made absolute.
`static boolean`	`mkdirs(FileSystem fs, Path dir, FsPermission permission)` Create a directory with the provided permission.
`boolean`	`mkdirs(Path f)` Call `mkdirs(Path, FsPermission)` with default permission.
`abstract boolean`	`mkdirs(Path f, FsPermission permission)` Make the given file and all non-existent parents into directories.
`void`	`modifyAclEntries(Path path, List<AclEntry> aclSpec)` Modifies ACL entries of files and directories.
`void`	`moveFromLocalFile(Path[] srcs, Path dst)` The src files is on the local disk.
`void`	`moveFromLocalFile(Path src, Path dst)` The src file is on the local disk.
`void`	`moveToLocalFile(Path src, Path dst)` Copy a file to the local filesystem, then delete it from the remote filesystem (if successfully copied).
`void`	`msync()` Synchronize client metadata state.
`static FileSystem`	`newInstance(Configuration conf)` Returns a unique configured FileSystem implementation for the default filesystem of the supplied configuration.
`static FileSystem`	`newInstance(URI uri, Configuration config)` Returns the FileSystem for this URI's scheme and authority.
`static FileSystem`	`newInstance(URI uri, Configuration conf, String user)` Returns the FileSystem for this URI's scheme and authority and the given user.
`static LocalFileSystem`	`newInstanceLocal(Configuration conf)` Get a unique local FileSystem object.
`FSDataInputStream`	`open(Path f)` Opens an FSDataInputStream at the indicated Path.
`FSDataInputStream`	`open(PathHandle fd)` Open an FSDataInputStream matching the PathHandle instance.
`FSDataInputStream`	`open(PathHandle fd, int bufferSize)` Open an FSDataInputStream matching the PathHandle instance.
`abstract FSDataInputStream`	`open(Path f, int bufferSize)` Opens an FSDataInputStream at the indicated Path.
`protected FSDataOutputStream`	`primitiveCreate(Path f, FsPermission absolutePermission, EnumSet<CreateFlag> flag, int bufferSize, short replication, long blockSize, Progressable progress, org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt)` Deprecated.
`protected boolean`	`primitiveMkdir(Path f, FsPermission absolutePermission)` Deprecated.
`protected void`	`primitiveMkdir(Path f, FsPermission absolutePermission, boolean createParent)` Deprecated.
`static void`	`printStatistics()` Print all statistics for all file systems to `System.out`
`protected void`	`processDeleteOnExit()` Delete all paths that were marked as delete-on-exit.
`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.
`abstract boolean`	`rename(Path src, Path dst)` Renames Path src to Path dst.
`protected void`	`rename(Path src, Path dst, org.apache.hadoop.fs.Options.Rename... options)` Deprecated.
`void`	`renameSnapshot(Path path, String snapshotOldName, String snapshotNewName)` Rename a snapshot.
`protected Path`	`resolveLink(Path f)` See `AbstractFileSystem.getLinkTarget(Path)`.
`Path`	`resolvePath(Path p)` Return the fully-qualified path of path, resolving the path through any 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.
`static void`	`setDefaultUri(Configuration conf, String uri)` Set the default FileSystem URI in a configuration.
`static void`	`setDefaultUri(Configuration conf, URI uri)` Set the default FileSystem URI in a configuration.
`void`	`setOwner(Path p, String username, String groupname)` Set owner of a path (i.e.
`void`	`setPermission(Path p, FsPermission permission)` Set permission of a path.
`void`	`setQuota(Path src, long namespaceQuota, long storagespaceQuota)` Set quota for the given `Path`.
`void`	`setQuotaByStorageType(Path src, StorageType type, long quota)` Set per storage type quota for the given `Path`.
`boolean`	`setReplication(Path src, short replication)` Set the replication for an existing file.
`void`	`setStoragePolicy(Path src, String policyName)` Set the storage policy for a given file or directory.
`void`	`setTimes(Path p, long mtime, long atime)` Set access time of a file.
`void`	`setVerifyChecksum(boolean verifyChecksum)` Set the verify checksum flag.
`abstract void`	`setWorkingDirectory(Path new_dir)` Set the current working directory for the given FileSystem.
`void`	`setWriteChecksum(boolean writeChecksum)` Set the write checksum flag.
`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.
`Path`	`startLocalOutput(Path fsOutputFile, Path tmpLocalFile)` Returns a local file that the user can write output to.
`boolean`	`supportsSymlinks()` See `AbstractFileSystem.supportsSymlinks()`.
`boolean`	`truncate(Path f, long newLength)` Truncate the file in the indicated path to the indicated size.
`void`	`unsetStoragePolicy(Path src)` Unset the storage policy set for a given file or directory.

Methods inherited from class org.apache.hadoop.conf.Configured
getConf, setConf

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.security.token.DelegationTokenIssuer
addDelegationTokens, getAdditionalTokenIssuers, getDelegationToken

- Field Detail
  - FS_DEFAULT_NAME_KEY
```
public static final String FS_DEFAULT_NAME_KEY
```
    See Also:
    
    Constant Field Values
  - DEFAULT_FS
```
public static final String DEFAULT_FS
```
    See Also:
    
    Constant Field Values
  - SHUTDOWN_HOOK_PRIORITY
```
public static final int SHUTDOWN_HOOK_PRIORITY
```
    Priority of the FileSystem shutdown hook: 10.
    
    See Also:
    
    Constant Field Values
  - TRASH_PREFIX
```
public static final String TRASH_PREFIX
```
    Prefix for trash directory: ".Trash".
    
    See Also:
    
    Constant Field Values
  - USER_HOME_PREFIX
```
public static final String USER_HOME_PREFIX
```
    See Also:
    
    Constant Field Values
  - statistics
```
protected org.apache.hadoop.fs.FileSystem.Statistics statistics
```
    The statistics for this file system.
- Constructor Detail
  - FileSystem
```
protected FileSystem()
```
- Method Detail
  - get
```
public static FileSystem get(URI uri,
                             Configuration conf,
                             String user)
                      throws IOException,
                             InterruptedException
```
    Get a FileSystem instance based on the uri, the passed in configuration and the user.
    
    Parameters:
    
    uri - of the filesystem
    
    conf - the configuration to use
    
    user - to perform the get as
    
    Returns:
    
    the filesystem instance
    
    Throws:
    
    IOException - failure to load
    
    InterruptedException - If the UGI.doAs() call was somehow interrupted.
  - get
```
public static FileSystem get(Configuration conf)
                      throws IOException
```
    Returns the configured FileSystem implementation.
    
    Parameters:
    
    conf - the configuration to use
    
    Throws:
    
    IOException
  - getDefaultUri
```
public static URI getDefaultUri(Configuration conf)
```
    Get the default FileSystem URI from a configuration.
    
    Parameters:
    
    conf - the configuration to use
    
    Returns:
    
    the uri of the default filesystem
  - setDefaultUri
```
public static void setDefaultUri(Configuration conf,
                                 URI uri)
```
    Set the default FileSystem URI in a configuration.
    
    Parameters:
    
    conf - the configuration to alter
    
    uri - the new default filesystem uri
  - setDefaultUri
```
public static void setDefaultUri(Configuration conf,
                                 String uri)
```
    Set the default FileSystem URI in a configuration.
    
    Parameters:
    
    conf - the configuration to alter
    
    uri - the new default filesystem uri
  - initialize
```
public void initialize(URI name,
                       Configuration conf)
                throws IOException
```
    Initialize a FileSystem. Called after the new FileSystem instance is constructed, and before it is ready for use. FileSystem implementations overriding this method MUST forward it to their superclass, though the order in which it is done, and whether to alter the configuration before the invocation are options of the subclass.
    
    Parameters:
    
    name - a URI whose authority section names the host, port, etc. for this FileSystem
    
    conf - the configuration
    
    Throws:
    
    IOException - on any failure to initialize this instance.
    
    IllegalArgumentException - if the URI is considered invalid.
  - getScheme
```
public String getScheme()
```
    Return the protocol scheme for this FileSystem.
    This implementation throws an UnsupportedOperationException.
    
    Returns:
    
    the protocol scheme for this FileSystem.
    
    Throws:
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - getUri
```
public abstract URI getUri()
```
    Returns a URI which identifies this FileSystem.
    
    Returns:
    
    the URI of this filesystem.
  - getCanonicalUri
```
protected URI getCanonicalUri()
```
    Return a canonicalized form of this FileSystem's URI. The default implementation simply calls canonicalizeUri(URI) on the filesystem's own URI, so subclasses typically only need to implement that method.
    
    See Also:
    
    canonicalizeUri(URI)
  - canonicalizeUri
```
protected URI canonicalizeUri(URI uri)
```
    Canonicalize the given URI. This is implementation-dependent, and may for example consist of canonicalizing the hostname using DNS and adding the default port if not specified. The default implementation simply fills in the default port if not specified and if getDefaultPort() returns a default port.
    
    Returns:
    
    URI
    
    See Also:
    
    NetUtils.getCanonicalUri(URI, int)
  - getDefaultPort
```
protected int getDefaultPort()
```
    Get the default port for this FileSystem.
    
    Returns:
    
    the default port or 0 if there isn't one
  - getFSofPath
```
protected static FileSystem getFSofPath(Path absOrFqPath,
                                        Configuration conf)
                                 throws UnsupportedFileSystemException,
                                        IOException
```
    Throws:
    
    UnsupportedFileSystemException
    
    IOException
  - getCanonicalServiceName
```
@InterfaceAudience.Public
 @InterfaceStability.Evolving
public String getCanonicalServiceName()
```
    Get a canonical service name for this FileSystem. The token cache is the only user of the canonical service name, and uses it to lookup this FileSystem's service tokens. If the file system provides a token of its own then it must have a canonical name, otherwise the canonical name can be null. Default implementation: If the FileSystem has child file systems (such as an embedded file system) then it is assumed that the FS has no tokens of its own and hence returns a null name; otherwise a service name is built using Uri and port.
    
    Specified by:
    
    getCanonicalServiceName in interface org.apache.hadoop.security.token.DelegationTokenIssuer
    
    Returns:
    
    a service string that uniquely identifies this file system, null if the filesystem does not implement tokens
    
    See Also:
    
    SecurityUtil.buildDTServiceName(URI, int)
  - getName
```
@Deprecated
public String getName()
```
    Deprecated. call getUri() instead.
  - getNamed
```
@Deprecated
public static FileSystem getNamed(String name,
                                              Configuration conf)
                                       throws IOException
```
    Deprecated. call get(URI, Configuration) instead.
    
    Throws:
    
    IOException
  - getLocal
```
public static LocalFileSystem getLocal(Configuration conf)
                                throws IOException
```
    Get the local FileSystem.
    
    Parameters:
    
    conf - the configuration to configure the FileSystem with if it is newly instantiated.
    
    Returns:
    
    a LocalFileSystem
    
    Throws:
    
    IOException - if somehow the local FS cannot be instantiated.
  - get
```
public static FileSystem get(URI uri,
                             Configuration conf)
                      throws IOException
```
    Get a FileSystem for this URI's scheme and authority.
    1. If the configuration has the property "fs.$SCHEME.impl.disable.cache" set to true, a new instance will be created, initialized with the supplied URI and configuration, then returned without being cached.
    2. If the there is a cached FS instance matching the same URI, it will be returned.
    3. Otherwise: a new FS instance will be created, initialized with the configuration and URI, cached and returned to the caller.
    Throws:
    
    IOException - if the FileSystem cannot be instantiated.
  - newInstance
```
public static FileSystem newInstance(URI uri,
                                     Configuration conf,
                                     String user)
                              throws IOException,
                                     InterruptedException
```
    Returns the FileSystem for this URI's scheme and authority and the given user. Internally invokes newInstance(URI, Configuration)
    
    Parameters:
    
    uri - of the filesystem
    
    conf - the configuration to use
    
    user - to perform the get as
    
    Returns:
    
    filesystem instance
    
    Throws:
    
    IOException - if the FileSystem cannot be instantiated.
    
    InterruptedException - If the UGI.doAs() call was somehow interrupted.
  - newInstance
```
public static FileSystem newInstance(URI uri,
                                     Configuration config)
                              throws IOException
```
    Returns the FileSystem for this URI's scheme and authority. The entire URI is passed to the FileSystem instance's initialize method. This always returns a new FileSystem object.
    
    Parameters:
    
    uri - FS URI
    
    config - configuration to use
    
    Returns:
    
    the new FS instance
    
    Throws:
    
    IOException - FS creation or initialization failure.
  - newInstance
```
public static FileSystem newInstance(Configuration conf)
                              throws IOException
```
    Returns a unique configured FileSystem implementation for the default filesystem of the supplied configuration. This always returns a new FileSystem object.
    
    Parameters:
    
    conf - the configuration to use
    
    Returns:
    
    the new FS instance
    
    Throws:
    
    IOException - FS creation or initialization failure.
  - newInstanceLocal
```
public static LocalFileSystem newInstanceLocal(Configuration conf)
                                        throws IOException
```
    Get a unique local FileSystem object.
    
    Parameters:
    
    conf - the configuration to configure the FileSystem with
    
    Returns:
    
    a new LocalFileSystem object.
    
    Throws:
    
    IOException - FS creation or initialization failure.
  - closeAll
```
public static void closeAll()
                     throws IOException
```
    Close all cached FileSystem instances. After this operation, they may not be used in any operations.
    
    Throws:
    
    IOException - a problem arose closing one or more filesystem.
  - closeAllForUGI
```
public static void closeAllForUGI(UserGroupInformation ugi)
                           throws IOException
```
    Close all cached FileSystem instances for a given UGI. Be sure those filesystems are not used anymore.
    
    Parameters:
    
    ugi - user group info to close
    
    Throws:
    
    IOException - a problem arose closing one or more filesystem.
  - makeQualified
```
public Path makeQualified(Path path)
```
    Qualify a path to one which uses this FileSystem and, if relative, made absolute.
    
    Parameters:
    
    path - to qualify.
    
    Returns:
    
    this path if it contains a scheme and authority and is absolute, or a new path that includes a path and authority and is fully qualified
    
    Throws:
    
    IllegalArgumentException - if the path has a schema/URI different from this FileSystem.
    
    See Also:
    
    Path.makeQualified(URI, Path)
  - create
```
public static FSDataOutputStream create(FileSystem fs,
                                        Path file,
                                        FsPermission permission)
                                 throws IOException
```
    Create a file with the provided permission. The permission of the file is set to be the provided permission as in setPermission, not permission&~umask The HDFS implementation is implemented using two RPCs. It is understood that it is inefficient, but the implementation is thread-safe. The other option is to change the value of umask in configuration to be 0, but it is not thread-safe.
    
    Parameters:
    
    fs - FileSystem
    
    file - the name of the file to be created
    
    permission - the permission of the file
    
    Returns:
    
    an output stream
    
    Throws:
    
    IOException - IO failure
  - mkdirs
```
public static boolean mkdirs(FileSystem fs,
                             Path dir,
                             FsPermission permission)
                      throws IOException
```
    Create a directory with the provided permission. The permission of the directory is set to be the provided permission as in setPermission, not permission&~umask
    
    Parameters:
    
    fs - FileSystem handle
    
    dir - the name of the directory to be created
    
    permission - the permission of the directory
    
    Returns:
    
    true if the directory creation succeeds; false otherwise
    
    Throws:
    
    IOException - A problem creating the directories.
    
    See Also:
    
    create(FileSystem, Path, FsPermission)
  - checkPath
```
protected void checkPath(Path path)
```
    Check that a Path belongs to this FileSystem. The base implementation performs case insensitive equality checks of the URIs' schemes and authorities. Subclasses may implement slightly different checks.
    
    Parameters:
    
    path - to check
    
    Throws:
    
    IllegalArgumentException - if the path is not considered to be part of this FileSystem.
  - getFileBlockLocations
```
public BlockLocation[] getFileBlockLocations(FileStatus file,
                                             long start,
                                             long len)
                                      throws IOException
```
    Return an array containing hostnames, offset and size of portions of the given file. For nonexistent file or regions, null is returned.
```
   if f == null :
     result = null
   elif f.getLen() <= start:
     result = []
   else result = [ locations(FS, b) for b in blocks(FS, p, s, s+l)]
 
```
    This call is most helpful with and distributed filesystem where the hostnames of machines that contain blocks of the given file can be determined. The default implementation returns an array containing one element:
```
 BlockLocation( { "localhost:9866" },  { "localhost" }, 0, file.getLen())
 
```
    In HDFS, if file is three-replicated, the returned array contains elements like:
```
 BlockLocation(offset: 0, length: BLOCK_SIZE,
   hosts: {"host1:9866", "host2:9866, host3:9866"})
 BlockLocation(offset: BLOCK_SIZE, length: BLOCK_SIZE,
   hosts: {"host2:9866", "host3:9866, host4:9866"})
 
```
    And if a file is erasure-coded, the returned BlockLocation are logical block groups. Suppose we have a RS_3_2 coded file (3 data units and 2 parity units). 1. If the file size is less than one stripe size, say 2 * CELL_SIZE, then there will be one BlockLocation returned, with 0 offset, actual file size and 4 hosts (2 data blocks and 2 parity blocks) hosting the actual blocks. 3. If the file size is less than one group size but greater than one stripe size, then there will be one BlockLocation returned, with 0 offset, actual file size with 5 hosts (3 data blocks and 2 parity blocks) hosting the actual blocks. 4. If the file size is greater than one group size, 3 * BLOCK_SIZE + 123 for example, then the result will be like:
```
 BlockLocation(offset: 0, length: 3 * BLOCK_SIZE, hosts: {"host1:9866",
   "host2:9866","host3:9866","host4:9866","host5:9866"})
 BlockLocation(offset: 3 * BLOCK_SIZE, length: 123, hosts: {"host1:9866",
   "host4:9866", "host5:9866"})
 
```
    Parameters:
    
    file - FilesStatus to get data from
    
    start - offset into the given file
    
    len - length for which to get locations for
    
    Throws:
    
    IOException - IO failure
  - getFileBlockLocations
```
public BlockLocation[] getFileBlockLocations(Path p,
                                             long start,
                                             long len)
                                      throws IOException
```
    Return an array containing hostnames, offset and size of portions of the given file. For a nonexistent file or regions, null is returned. This call is most helpful with location-aware distributed filesystems, where it returns hostnames of machines that contain the given file. A FileSystem will normally return the equivalent result of passing the FileStatus of the path to getFileBlockLocations(FileStatus, long, long)
    
    Parameters:
    
    p - path is used to identify an FS since an FS could have another FS that it could be delegating the call to
    
    start - offset into the given file
    
    len - length for which to get locations for
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - IO failure
  - getServerDefaults
```
@Deprecated
public FsServerDefaults getServerDefaults()
                                               throws IOException
```
    Deprecated. use getServerDefaults(Path) instead
    
    Return a set of server default configuration values.
    
    Returns:
    
    server default configuration values
    
    Throws:
    
    IOException - IO failure
  - getServerDefaults
```
public FsServerDefaults getServerDefaults(Path p)
                                   throws IOException
```
    Return a set of server default configuration values.
    
    Parameters:
    
    p - path is used to identify an FS since an FS could have another FS that it could be delegating the call to
    
    Returns:
    
    server default configuration values
    
    Throws:
    
    IOException - IO failure
  - resolvePath
```
public Path resolvePath(Path p)
                 throws IOException
```
    Return the fully-qualified path of path, resolving the path through any symlinks or mount point.
    
    Parameters:
    
    p - path to be resolved
    
    Returns:
    
    fully qualified path
    
    Throws:
    
    FileNotFoundException - if the path is not present
    
    IOException - for any other error
  - open
```
public abstract FSDataInputStream open(Path f,
                                       int bufferSize)
                                throws IOException
```
    Opens an FSDataInputStream at the indicated Path.
    
    Parameters:
    
    f - the file name to open
    
    bufferSize - the size of the buffer to be used.
    
    Throws:
    
    IOException - IO failure
  - open
```
public FSDataInputStream open(Path f)
                       throws IOException
```
    Opens an FSDataInputStream at the indicated Path.
    
    Parameters:
    
    f - the file to open
    
    Throws:
    
    IOException - IO failure
  - open
```
public FSDataInputStream open(PathHandle fd)
                       throws IOException
```
    Open an FSDataInputStream matching the PathHandle instance. The implementation may encode metadata in PathHandle to address the resource directly and verify that the resource referenced satisfies constraints specified at its construciton.
    
    Parameters:
    
    fd - PathHandle object returned by the FS authority.
    
    Throws:
    
    InvalidPathHandleException - If PathHandle constraints are not satisfied
    
    IOException - IO failure
    
    UnsupportedOperationException - If open(PathHandle, int) not overridden by subclass
  - open
```
public FSDataInputStream open(PathHandle fd,
                              int bufferSize)
                       throws IOException
```
    Open an FSDataInputStream matching the PathHandle instance. The implementation may encode metadata in PathHandle to address the resource directly and verify that the resource referenced satisfies constraints specified at its construciton.
    
    Parameters:
    
    fd - PathHandle object returned by the FS authority.
    
    bufferSize - the size of the buffer to use
    
    Throws:
    
    InvalidPathHandleException - If PathHandle constraints are not satisfied
    
    IOException - IO failure
    
    UnsupportedOperationException - If not overridden by subclass
  - getPathHandle
```
public final PathHandle getPathHandle(FileStatus stat,
                                      org.apache.hadoop.fs.Options.HandleOpt... opt)
```
    Create a durable, serializable handle to the referent of the given entity.
    
    Parameters:
    
    stat - Referent in the target FileSystem
    
    opt - If absent, assume Options.HandleOpt.path().
    
    Throws:
    
    IllegalArgumentException - If the FileStatus does not belong to this FileSystem
    
    UnsupportedOperationException - If createPathHandle(org.apache.hadoop.fs.FileStatus, org.apache.hadoop.fs.Options.HandleOpt...) not overridden by subclass.
    
    UnsupportedOperationException - If this FileSystem cannot enforce the specified constraints.
  - createPathHandle
```
protected PathHandle createPathHandle(FileStatus stat,
                                      org.apache.hadoop.fs.Options.HandleOpt... opt)
```
    Hook to implement support for PathHandle operations.
    
    Parameters:
    
    stat - Referent in the target FileSystem
    
    opt - Constraints that determine the validity of the PathHandle reference.
  - create
```
public FSDataOutputStream create(Path f)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path. Files are overwritten by default.
    
    Parameters:
    
    f - the file to create
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 boolean overwrite)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path.
    
    Parameters:
    
    f - the file to create
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an exception will be thrown.
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 Progressable progress)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.
    
    Parameters:
    
    f - the file to create
    
    progress - to report progress
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 short replication)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path. Files are overwritten by default.
    
    Parameters:
    
    f - the file to create
    
    replication - the replication factor
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 short replication,
                                 Progressable progress)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.
    
    Parameters:
    
    f - the file to create
    
    replication - the replication factor
    
    progress - to report progress
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 boolean overwrite,
                                 int bufferSize)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path.
    
    Parameters:
    
    f - the file to create
    
    overwrite - if a path with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 boolean overwrite,
                                 int bufferSize,
                                 Progressable progress)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting. The frequency of callbacks is implementation-specific; it may be "none".
    
    Parameters:
    
    f - the path of the file to open
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 boolean overwrite,
                                 int bufferSize,
                                 short replication,
                                 long blockSize)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path.
    
    Parameters:
    
    f - the file name to open
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    Throws:
    
    IOException - IO failure
  - create
```
public FSDataOutputStream create(Path f,
                                 boolean overwrite,
                                 int bufferSize,
                                 short replication,
                                 long blockSize,
                                 Progressable progress)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting.
    
    Parameters:
    
    f - the file name to open
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    Throws:
    
    IOException - IO failure
  - create
```
public abstract FSDataOutputStream create(Path f,
                                          FsPermission permission,
                                          boolean overwrite,
                                          int bufferSize,
                                          short replication,
                                          long blockSize,
                                          Progressable progress)
                                   throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting.
    
    Parameters:
    
    f - the file name to open
    
    permission - file permission
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - create
```
public FSDataOutputStream create(Path f,
                                 FsPermission permission,
                                 EnumSet<CreateFlag> flags,
                                 int bufferSize,
                                 short replication,
                                 long blockSize,
                                 Progressable progress)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with write-progress reporting.
    
    Parameters:
    
    f - the file name to open
    
    permission - file permission
    
    flags - CreateFlags to use for this stream.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - create
```
public FSDataOutputStream create(Path f,
                                 FsPermission permission,
                                 EnumSet<CreateFlag> flags,
                                 int bufferSize,
                                 short replication,
                                 long blockSize,
                                 Progressable progress,
                                 org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt)
                          throws IOException
```
    Create an FSDataOutputStream at the indicated Path with a custom checksum option.
    
    Parameters:
    
    f - the file name to open
    
    permission - file permission
    
    flags - CreateFlags to use for this stream.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    checksumOpt - checksum parameter. If null, the values found in conf will be used.
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - primitiveCreate
```
@Deprecated
protected FSDataOutputStream primitiveCreate(Path f,
                                                         FsPermission absolutePermission,
                                                         EnumSet<CreateFlag> flag,
                                                         int bufferSize,
                                                         short replication,
                                                         long blockSize,
                                                         Progressable progress,
                                                         org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt)
                                                  throws IOException
```
    Deprecated.
    
    This create has been added to support the FileContext that processes the permission with umask before calling this method. This a temporary method added to support the transition from FileSystem to FileContext for user applications.
    
    Throws:
    
    IOException - IO failure
  - primitiveMkdir
```
@Deprecated
protected boolean primitiveMkdir(Path f,
                                             FsPermission absolutePermission)
                                      throws IOException
```
    Deprecated.
    
    This version of the mkdirs method assumes that the permission is absolute. It has been added to support the FileContext that processes the permission with umask before calling this method. This a temporary method added to support the transition from FileSystem to FileContext for user applications.
    
    Parameters:
    
    f - path
    
    absolutePermission - permissions
    
    Returns:
    
    true if the directory was actually created.
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    mkdirs(Path, FsPermission)
  - primitiveMkdir
```
@Deprecated
protected void primitiveMkdir(Path f,
                                          FsPermission absolutePermission,
                                          boolean createParent)
                                   throws IOException
```
    Deprecated.
    
    This version of the mkdirs method assumes that the permission is absolute. It has been added to support the FileContext that processes the permission with umask before calling this method. This a temporary method added to support the transition from FileSystem to FileContext for user applications.
    
    Throws:
    
    IOException
  - createNonRecursive
```
public FSDataOutputStream createNonRecursive(Path f,
                                             boolean overwrite,
                                             int bufferSize,
                                             short replication,
                                             long blockSize,
                                             Progressable progress)
                                      throws IOException
```
    Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.
    
    Parameters:
    
    f - the file name to open
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - createNonRecursive
```
public FSDataOutputStream createNonRecursive(Path f,
                                             FsPermission permission,
                                             boolean overwrite,
                                             int bufferSize,
                                             short replication,
                                             long blockSize,
                                             Progressable progress)
                                      throws IOException
```
    Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.
    
    Parameters:
    
    f - the file name to open
    
    permission - file permission
    
    overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - createNonRecursive
```
public FSDataOutputStream createNonRecursive(Path f,
                                             FsPermission permission,
                                             EnumSet<CreateFlag> flags,
                                             int bufferSize,
                                             short replication,
                                             long blockSize,
                                             Progressable progress)
                                      throws IOException
```
    Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.
    
    Parameters:
    
    f - the file name to open
    
    permission - file permission
    
    flags - CreateFlags to use for this stream.
    
    bufferSize - the size of the buffer to be used.
    
    replication - required block replication for the file.
    
    blockSize - block size
    
    progress - the progress reporter
    
    Throws:
    
    IOException - IO failure
    
    See Also:
    
    setPermission(Path, FsPermission)
  - createNewFile
```
public boolean createNewFile(Path f)
                      throws IOException
```
    Creates the given Path as a brand-new zero-length file. If create fails, or if it already existed, return false. Important: the default implementation is not atomic
    
    Parameters:
    
    f - path to use for create
    
    Throws:
    
    IOException - IO failure
  - append
```
public FSDataOutputStream append(Path f)
                          throws IOException
```
    Append to an existing file (optional operation). Same as append(f, getConf().getInt(IO_FILE_BUFFER_SIZE_KEY, IO_FILE_BUFFER_SIZE_DEFAULT), null)
    
    Parameters:
    
    f - the existing file to be appended.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - append
```
public FSDataOutputStream append(Path f,
                                 int bufferSize)
                          throws IOException
```
    Append to an existing file (optional operation). Same as append(f, bufferSize, null).
    
    Parameters:
    
    f - the existing file to be appended.
    
    bufferSize - the size of the buffer to be used.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - append
```
public abstract FSDataOutputStream append(Path f,
                                          int bufferSize,
                                          Progressable progress)
                                   throws IOException
```
    Append to an existing file (optional operation).
    
    Parameters:
    
    f - the existing file to be appended.
    
    bufferSize - the size of the buffer to be used.
    
    progress - for reporting progress if it is not null.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - concat
```
public void concat(Path trg,
                   Path[] psrcs)
            throws IOException
```
    Concat existing files together.
    
    Parameters:
    
    trg - the path to the target destination.
    
    psrcs - the paths to the sources to use for the concatenation.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - getReplication
```
@Deprecated
public short getReplication(Path src)
                                 throws IOException
```
    Deprecated. Use getFileStatus(Path) instead
    
    Get the replication factor.
    
    Parameters:
    
    src - file name
    
    Returns:
    
    file replication
    
    Throws:
    
    FileNotFoundException - if the path does not resolve.
    
    IOException - an IO failure
  - setReplication
```
public boolean setReplication(Path src,
                              short replication)
                       throws IOException
```
    Set the replication for an existing file. If a filesystem does not support replication, it will always return true: the check for a file existing may be bypassed. This is the default behavior.
    
    Parameters:
    
    src - file name
    
    replication - new replication
    
    Returns:
    
    true if successful, or the feature in unsupported; false if replication is supported but the file does not exist, or is a directory
    
    Throws:
    
    IOException
  - rename
```
public abstract boolean rename(Path src,
                               Path dst)
                        throws IOException
```
    Renames Path src to Path dst.
    
    Parameters:
    
    src - path to be renamed
    
    dst - new path after rename
    
    Returns:
    
    true if rename is successful
    
    Throws:
    
    IOException - on failure
  - rename
```
@Deprecated
protected void rename(Path src,
                                  Path dst,
                                  org.apache.hadoop.fs.Options.Rename... options)
                           throws IOException
```
    Deprecated.
    Renames Path src to Path dst
    - Fails if src is a file and dst is a directory.
    - Fails if src is a directory and dst is a file.
    - Fails if the parent of dst does not exist or is a file.
    If OVERWRITE option is not passed as an argument, rename fails if the dst already exists.
    If OVERWRITE option is passed as an argument, rename overwrites the dst if it is a file or an empty directory. Rename fails if dst is a non-empty directory.
    Note that atomicity of rename is dependent on the file system implementation. Please refer to the file system documentation for details. This default implementation is non atomic.
    This method is deprecated since it is a temporary method added to support the transition from FileSystem to FileContext for user applications.
    Parameters:
    
    src - path to be renamed
    
    dst - new path after rename
    
    Throws:
    
    FileNotFoundException - src path does not exist, or the parent path of dst does not exist.
    
    FileAlreadyExistsException - dest path exists and is a file
    
    ParentNotDirectoryException - if the parent path of dest is not a directory
    
    IOException - on failure
  - truncate
```
public boolean truncate(Path f,
                        long newLength)
                 throws IOException
```
    Truncate the file in the indicated path to the indicated size.
    - Fails if path is a directory.
    - Fails if path does not exist.
    - Fails if path is not closed.
    - Fails if new size is greater than current size.
    Parameters:
    
    f - The path to the file to be truncated
    
    newLength - The size the file is to be truncated to
    
    Returns:
    
    true if the file has been truncated to the desired newLength and is immediately available to be reused for write operations such as append, or false if a background process of adjusting the length of the last block has been started, and clients should wait for it to complete before proceeding with further file updates.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default).
  - delete
```
@Deprecated
public boolean delete(Path f)
                           throws IOException
```
    Deprecated. Use delete(Path, boolean) instead.
    
    Delete a file/directory.
    
    Throws:
    
    IOException
  - delete
```
public abstract boolean delete(Path f,
                               boolean recursive)
                        throws IOException
```
    Delete a file.
    
    Parameters:
    
    f - the path to delete.
    
    recursive - if path is a directory and set to true, the directory is deleted else throws an exception. In case of a file the recursive can be set to either true or false.
    
    Returns:
    
    true if delete is successful else false.
    
    Throws:
    
    IOException - IO failure
  - deleteOnExit
```
public boolean deleteOnExit(Path f)
                     throws IOException
```
    Mark a path to be deleted when its FileSystem is closed. When the JVM shuts down cleanly, all cached FileSystem objects will be closed automatically. These the marked paths will be deleted as a result. If a FileSystem instance is not cached, i.e. has been created with createFileSystem(URI, Configuration), then the paths will be deleted in when close() is called on that instance. The path must exist in the filesystem at the time of the method call; it does not have to exist at the time of JVM shutdown. Notes
    1. Clean shutdown of the JVM cannot be guaranteed.
    2. The time to shut down a FileSystem will depends on the number of files to delete. For filesystems where the cost of checking for the existence of a file/directory and the actual delete operation (for example: object stores) is high, the time to shutdown the JVM can be significantly extended by over-use of this feature.
    3. Connectivity problems with a remote filesystem may delay shutdown further, and may cause the files to not be deleted.
    Parameters:
    
    f - the path to delete.
    
    Returns:
    
    true if deleteOnExit is successful, otherwise false.
    
    Throws:
    
    IOException - IO failure
  - cancelDeleteOnExit
```
public boolean cancelDeleteOnExit(Path f)
```
    Cancel the scheduled deletion of the path when the FileSystem is closed.
    
    Parameters:
    
    f - the path to cancel deletion
    
    Returns:
    
    true if the path was found in the delete-on-exit list.
  - processDeleteOnExit
```
protected void processDeleteOnExit()
```
    Delete all paths that were marked as delete-on-exit. This recursively deletes all files and directories in the specified paths. The time to process this operation is O(paths), with the actual time dependent on the time for existence and deletion operations to complete, successfully or not.
  - exists
```
public boolean exists(Path f)
               throws IOException
```
    Check if a path exists. It is highly discouraged to call this method back to back with other getFileStatus(Path) calls, as this will involve multiple redundant RPC calls in HDFS.
    
    Parameters:
    
    f - source path
    
    Returns:
    
    true if the path exists
    
    Throws:
    
    IOException - IO failure
  - isDirectory
```
@Deprecated
public boolean isDirectory(Path f)
                                throws IOException
```
    Deprecated. Use getFileStatus(Path) instead
    
    True iff the named path is a directory. Note: Avoid using this method. Instead reuse the FileStatus returned by getFileStatus() or listStatus() methods.
    
    Parameters:
    
    f - path to check
    
    Throws:
    
    IOException - IO failure
  - isFile
```
@Deprecated
public boolean isFile(Path f)
                           throws IOException
```
    Deprecated. Use getFileStatus(Path) instead
    
    True iff the named path is a regular file. Note: Avoid using this method. Instead reuse the FileStatus returned by getFileStatus(Path) or listStatus() methods.
    
    Parameters:
    
    f - path to check
    
    Throws:
    
    IOException - IO failure
  - getLength
```
@Deprecated
public long getLength(Path f)
                           throws IOException
```
    Deprecated. Use getFileStatus(Path) instead.
    
    The number of bytes in a file.
    
    Returns:
    
    the number of bytes; 0 for a directory
    
    Throws:
    
    FileNotFoundException - if the path does not resolve
    
    IOException - IO failure
  - getContentSummary
```
public ContentSummary getContentSummary(Path f)
                                 throws IOException
```
    Return the ContentSummary of a given Path.
    
    Parameters:
    
    f - path to use
    
    Throws:
    
    FileNotFoundException - if the path does not resolve
    
    IOException - IO failure
  - getQuotaUsage
```
public QuotaUsage getQuotaUsage(Path f)
                         throws IOException
```
    Return the QuotaUsage of a given Path.
    
    Parameters:
    
    f - path to use
    
    Returns:
    
    the quota usage
    
    Throws:
    
    IOException - IO failure
  - setQuota
```
public void setQuota(Path src,
                     long namespaceQuota,
                     long storagespaceQuota)
              throws IOException
```
    Set quota for the given Path.
    
    Parameters:
    
    src - the target path to set quota for
    
    namespaceQuota - the namespace quota (i.e., # of files/directories) to set
    
    storagespaceQuota - the storage space quota to set
    
    Throws:
    
    IOException - IO failure
  - setQuotaByStorageType
```
public void setQuotaByStorageType(Path src,
                                  StorageType type,
                                  long quota)
                           throws IOException
```
    Set per storage type quota for the given Path.
    
    Parameters:
    
    src - the target path to set storage type quota for
    
    type - the storage type to set
    
    quota - the quota to set for the given storage type
    
    Throws:
    
    IOException - IO failure
  - listStatus
```
public abstract FileStatus[] listStatus(Path f)
                                 throws FileNotFoundException,
                                        IOException
```
    List the statuses of the files/directories in the given path if the path is a directory.
    Does not guarantee to return the List of files/directories status in a sorted order.
    Will not return null. Expect IOException upon access error.
    
    Parameters:
    
    f - given path
    
    Returns:
    
    the statuses of the files/directories in the given patch
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
  - listCorruptFileBlocks
```
public org.apache.hadoop.fs.RemoteIterator<Path> listCorruptFileBlocks(Path path)
                                                                throws IOException
```
    List corrupted file blocks.
    
    Returns:
    
    an iterator over the corrupt files under the given path (may contain duplicates if a file has more than one corrupt block)
    
    Throws:
    
    UnsupportedOperationException - if the operation is unsupported (default).
    
    IOException - IO failure
  - listStatus
```
public FileStatus[] listStatus(Path f,
                               PathFilter filter)
                        throws FileNotFoundException,
                               IOException
```
    Filter files/directories in the given path using the user-supplied path filter.
    Does not guarantee to return the List of files/directories status in a sorted order.
    
    Parameters:
    
    f - a path name
    
    filter - the user-supplied path filter
    
    Returns:
    
    an array of FileStatus objects for the files under the given path after applying the filter
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
  - listStatus
```
public FileStatus[] listStatus(Path[] files)
                        throws FileNotFoundException,
                               IOException
```
    Filter files/directories in the given list of paths using default path filter.
    Does not guarantee to return the List of files/directories status in a sorted order.
    
    Parameters:
    
    files - a list of paths
    
    Returns:
    
    a list of statuses for the files under the given paths after applying the filter default Path filter
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
  - listStatus
```
public FileStatus[] listStatus(Path[] files,
                               PathFilter filter)
                        throws FileNotFoundException,
                               IOException
```
    Filter files/directories in the given list of paths using user-supplied path filter.
    Does not guarantee to return the List of files/directories status in a sorted order.
    
    Parameters:
    
    files - a list of paths
    
    filter - the user-supplied path filter
    
    Returns:
    
    a list of statuses for the files under the given paths after applying the filter
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
  - globStatus
```
public FileStatus[] globStatus(Path pathPattern)
                        throws 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 that character a must be lexicographically less than or equal to character b.
    
    [^a]
    Matches a single character 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 the string set {ab, cde, cfh}
    
    Parameters:
    
    pathPattern - a glob specifying a path pattern
    
    Returns:
    
    an array of paths that match the path pattern
    
    Throws:
    
    IOException - IO failure
  - globStatus
```
public FileStatus[] globStatus(Path pathPattern,
                               PathFilter filter)
                        throws 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.
    
    Parameters:
    
    pathPattern - a glob specifying the path pattern
    
    filter - a user-supplied path filter
    
    Returns:
    
    null if pathPattern has no glob and the path does not exist an empty array if pathPattern has a glob and no path matches it else an array of FileStatus objects matching the pattern
    
    Throws:
    
    IOException - if any I/O error occurs when fetching file status
  - listLocatedStatus
```
public org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
                                                                         throws FileNotFoundException,
                                                                                IOException
```
    List the statuses of the files/directories in the given path if the path is a directory. Return the file's status and block locations If the path is a file. If a returned status is a file, it contains the file's block locations.
    
    Parameters:
    
    f - is the path
    
    Returns:
    
    an iterator that traverses statuses of the files/directories in the given path
    
    Throws:
    
    FileNotFoundException - If f does not exist
    
    IOException - If an I/O error occurred
  - listLocatedStatus
```
protected org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f,
                                                                                   PathFilter filter)
                                                                            throws FileNotFoundException,
                                                                                   IOException
```
    List a directory. The returned results include its block location if it is a file The results are filtered by the given path filter
    
    Parameters:
    
    f - a path
    
    filter - a path filter
    
    Returns:
    
    an iterator that traverses statuses of the files/directories in the given path
    
    Throws:
    
    FileNotFoundException - if f does not exist
    
    IOException - if any I/O error occurred
  - listStatusIterator
```
public org.apache.hadoop.fs.RemoteIterator<FileStatus> listStatusIterator(Path p)
                                                                   throws FileNotFoundException,
                                                                          IOException
```
    Returns a remote iterator so that followup calls are made on demand while consuming the entries. Each FileSystem implementation should override this method and provide a more efficient implementation, if possible. Does not guarantee to return the iterator that traverses statuses of the files in a sorted order.
    
    Parameters:
    
    p - target path
    
    Returns:
    
    remote iterator
    
    Throws:
    
    FileNotFoundException - if p does not exist
    
    IOException - if any I/O error occurred
  - listFiles
```
public org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listFiles(Path f,
                                                                        boolean recursive)
                                                                 throws FileNotFoundException,
                                                                        IOException
```
    List the statuses and block locations of the files in the given path. Does not guarantee to return the iterator that traverses statuses of the files in a sorted order.
```
 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.
 If the path is a file, return the file's status and block locations.
 
```
    Parameters:
    
    f - is the path
    
    recursive - if the subdirectories need to be traversed recursively
    
    Returns:
    
    an iterator that traverses statuses of the files
    
    Throws:
    
    FileNotFoundException - when the path does not exist;
    
    IOException - see specific implementation
  - getHomeDirectory
```
public Path getHomeDirectory()
```
    Return the current user's home directory in this FileSystem. The default implementation returns "/user/$USER/".
  - setWorkingDirectory
```
public abstract void setWorkingDirectory(Path new_dir)
```
    Set the current working directory for the given FileSystem. All relative paths will be resolved relative to it.
    
    Parameters:
    
    new_dir - Path of new working directory
  - getWorkingDirectory
```
public abstract Path getWorkingDirectory()
```
    Get the current working directory for the given FileSystem
    
    Returns:
    
    the directory pathname
  - getInitialWorkingDirectory
```
protected Path getInitialWorkingDirectory()
```
    Note: with the new FileContext class, getWorkingDirectory() will be removed. The working directory is implemented in FileContext. Some FileSystems like LocalFileSystem have an initial workingDir that we use as the starting workingDir. For other file systems like HDFS there is no built in notion of an initial workingDir.
    
    Returns:
    
    if there is built in notion of workingDir then it is returned; else a null is returned.
  - mkdirs
```
public boolean mkdirs(Path f)
               throws IOException
```
    Call mkdirs(Path, FsPermission) with default permission.
    
    Parameters:
    
    f - path
    
    Returns:
    
    true if the directory was created
    
    Throws:
    
    IOException - IO failure
  - mkdirs
```
public abstract boolean mkdirs(Path f,
                               FsPermission permission)
                        throws IOException
```
    Make the given file and all non-existent parents into directories. Has roughly the semantics of Unix @{code mkdir -p}. Existence of the directory hierarchy is not an error.
    
    Parameters:
    
    f - path to create
    
    permission - to apply to f
    
    Throws:
    
    IOException - IO failure
  - copyFromLocalFile
```
public void copyFromLocalFile(Path src,
                              Path dst)
                       throws IOException
```
    The src file is on the local disk. Add it to filesystem at the given dst name and the source is kept intact afterwards
    
    Parameters:
    
    src - path
    
    dst - path
    
    Throws:
    
    IOException - IO failure
  - moveFromLocalFile
```
public void moveFromLocalFile(Path[] srcs,
                              Path dst)
                       throws IOException
```
    The src files is on the local disk. Add it to filesystem at the given dst name, removing the source afterwards.
    
    Parameters:
    
    srcs - source paths
    
    dst - path
    
    Throws:
    
    IOException - IO failure
  - moveFromLocalFile
```
public void moveFromLocalFile(Path src,
                              Path dst)
                       throws IOException
```
    The src file is on the local disk. Add it to the filesystem at the given dst name, removing the source afterwards.
    
    Parameters:
    
    src - local path
    
    dst - path
    
    Throws:
    
    IOException - IO failure
  - copyFromLocalFile
```
public void copyFromLocalFile(boolean delSrc,
                              Path src,
                              Path dst)
                       throws IOException
```
    The src file is on the local disk. Add it to the filesystem at the given dst name. delSrc indicates if the source should be removed
    
    Parameters:
    
    delSrc - whether to delete the src
    
    src - path
    
    dst - path
    
    Throws:
    
    IOException
  - copyFromLocalFile
```
public void copyFromLocalFile(boolean delSrc,
                              boolean overwrite,
                              Path[] srcs,
                              Path dst)
                       throws IOException
```
    The src files are on the local disk. Add it to the filesystem at the given dst name. delSrc indicates if the source should be removed
    
    Parameters:
    
    delSrc - whether to delete the src
    
    overwrite - whether to overwrite an existing file
    
    srcs - array of paths which are source
    
    dst - path
    
    Throws:
    
    IOException - IO failure
  - copyFromLocalFile
```
public void copyFromLocalFile(boolean delSrc,
                              boolean overwrite,
                              Path src,
                              Path dst)
                       throws IOException
```
    The src file is on the local disk. Add it to the filesystem at the given dst name. delSrc indicates if the source should be removed
    
    Parameters:
    
    delSrc - whether to delete the src
    
    overwrite - whether to overwrite an existing file
    
    src - path
    
    dst - path
    
    Throws:
    
    IOException - IO failure
  - copyToLocalFile
```
public void copyToLocalFile(Path src,
                            Path dst)
                     throws IOException
```
    Copy it a file from the remote filesystem to the local one.
    
    Parameters:
    
    src - path src file in the remote filesystem
    
    dst - path local destination
    
    Throws:
    
    IOException - IO failure
  - moveToLocalFile
```
public void moveToLocalFile(Path src,
                            Path dst)
                     throws IOException
```
    Copy a file to the local filesystem, then delete it from the remote filesystem (if successfully copied).
    
    Parameters:
    
    src - path src file in the remote filesystem
    
    dst - path local destination
    
    Throws:
    
    IOException - IO failure
  - copyToLocalFile
```
public void copyToLocalFile(boolean delSrc,
                            Path src,
                            Path dst)
                     throws IOException
```
    Copy it a file from a remote filesystem to the local one. delSrc indicates if the src will be removed or not.
    
    Parameters:
    
    delSrc - whether to delete the src
    
    src - path src file in the remote filesystem
    
    dst - path local destination
    
    Throws:
    
    IOException - IO failure
  - copyToLocalFile
```
public void copyToLocalFile(boolean delSrc,
                            Path src,
                            Path dst,
                            boolean useRawLocalFileSystem)
                     throws IOException
```
    The src file is under this filesystem, and the dst is on the local disk. Copy it from the remote filesystem to the local dst name. delSrc indicates if the src will be removed or not. useRawLocalFileSystem indicates whether to use RawLocalFileSystem as the local file system or not. RawLocalFileSystem is non checksumming, So, It will not create any crc files at local.
    
    Parameters:
    
    delSrc - whether to delete the src
    
    src - path
    
    dst - path
    
    useRawLocalFileSystem - whether to use RawLocalFileSystem as local file system or not.
    
    Throws:
    
    IOException - for any IO error
  - startLocalOutput
```
public Path startLocalOutput(Path fsOutputFile,
                             Path tmpLocalFile)
                      throws IOException
```
    Returns a local file that the user can write output to. The caller provides both the eventual target name in this FileSystem and the local working file path. If this FileSystem is local, we write directly into the target. If the FileSystem is not local, we write into the tmp local area.
    
    Parameters:
    
    fsOutputFile - path of output file
    
    tmpLocalFile - path of local tmp file
    
    Throws:
    
    IOException - IO failure
  - completeLocalOutput
```
public void completeLocalOutput(Path fsOutputFile,
                                Path tmpLocalFile)
                         throws IOException
```
    Called when we're all done writing to the target. A local FS will do nothing, because we've written to exactly the right place. A remote FS will copy the contents of tmpLocalFile to the correct target at fsOutputFile.
    
    Parameters:
    
    fsOutputFile - path of output file
    
    tmpLocalFile - path to local tmp file
    
    Throws:
    
    IOException - IO failure
  - close
```
public void close()
           throws IOException
```
    Close this FileSystem instance. Will release any held locks, delete all files queued for deletion through calls to deleteOnExit(Path), and remove this FS instance from the cache, if cached. After this operation, the outcome of any method call on this FileSystem instance, or any input/output stream created by it is undefined.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Throws:
    
    IOException - IO failure
  - getUsed
```
public long getUsed()
             throws IOException
```
    Return the total size of all files in the filesystem.
    
    Throws:
    
    IOException - IO failure
  - getUsed
```
public long getUsed(Path path)
             throws IOException
```
    Return the total size of all files from a specified path.
    
    Throws:
    
    IOException - IO failure
  - getBlockSize
```
@Deprecated
public long getBlockSize(Path f)
                              throws IOException
```
    Deprecated. Use getFileStatus(Path) instead
    
    Get the block size for a particular file.
    
    Parameters:
    
    f - the filename
    
    Returns:
    
    the number of bytes in a block
    
    Throws:
    
    FileNotFoundException - if the path is not present
    
    IOException - IO failure
  - getDefaultBlockSize
```
@Deprecated
public long getDefaultBlockSize()
```
    Deprecated. use getDefaultBlockSize(Path) instead
    
    Return the number of bytes that large input files should be optimally be split into to minimize I/O time.
  - getDefaultBlockSize
```
public long getDefaultBlockSize(Path f)
```
    Return the number of bytes that large input files should be optimally be split into to minimize I/O time. The given path will be used to locate the actual filesystem. The full path does not have to exist.
    
    Parameters:
    
    f - path of file
    
    Returns:
    
    the default block size for the path's filesystem
  - getDefaultReplication
```
@Deprecated
public short getDefaultReplication()
```
    Deprecated. use getDefaultReplication(Path) instead
    
    Get the default replication.
    
    Returns:
    
    the replication; the default value is "1".
  - getDefaultReplication
```
public short getDefaultReplication(Path path)
```
    Get the default replication for a path. The given path will be used to locate the actual FileSystem to query. The full path does not have to exist.
    
    Parameters:
    
    path - of the file
    
    Returns:
    
    default replication for the path's filesystem
  - getFileStatus
```
public abstract FileStatus getFileStatus(Path f)
                                  throws IOException
```
    Return a file status object that represents the path.
    
    Parameters:
    
    f - The path we want information from
    
    Returns:
    
    a FileStatus object
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
  - 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
  - fixRelativePart
```
protected Path fixRelativePart(Path p)
```
    See FileContext.fixRelativePart(org.apache.hadoop.fs.Path).
  - createSymlink
```
public void createSymlink(Path target,
                          Path link,
                          boolean createParent)
                   throws AccessControlException,
                          FileAlreadyExistsException,
                          FileNotFoundException,
                          ParentNotDirectoryException,
                          UnsupportedFileSystemException,
                          IOException
```
    See FileContext.createSymlink(Path, Path, boolean).
    
    Throws:
    
    AccessControlException
    
    FileAlreadyExistsException
    
    FileNotFoundException
    
    ParentNotDirectoryException
    
    UnsupportedFileSystemException
    
    IOException
  - getFileLinkStatus
```
public FileStatus getFileLinkStatus(Path f)
                             throws AccessControlException,
                                    FileNotFoundException,
                                    UnsupportedFileSystemException,
                                    IOException
```
    See FileContext.getFileLinkStatus(Path).
    
    Throws:
    
    FileNotFoundException - when the path does not exist
    
    IOException - see specific implementation
    
    AccessControlException
    
    UnsupportedFileSystemException
  - supportsSymlinks
```
public boolean supportsSymlinks()
```
    See AbstractFileSystem.supportsSymlinks().
  - getLinkTarget
```
public Path getLinkTarget(Path f)
                   throws IOException
```
    See FileContext.getLinkTarget(Path).
    
    Throws:
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
    
    IOException
  - resolveLink
```
protected Path resolveLink(Path f)
                    throws IOException
```
    See AbstractFileSystem.getLinkTarget(Path).
    
    Throws:
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
    
    IOException
  - getFileChecksum
```
public FileChecksum getFileChecksum(Path f)
                             throws IOException
```
    Get the checksum of a file, if the FS supports checksums.
    
    Parameters:
    
    f - The file path
    
    Returns:
    
    The file checksum. The default return value is null, which indicates that no checksum algorithm is implemented in the corresponding FileSystem.
    
    Throws:
    
    IOException - IO failure
  - getFileChecksum
```
public FileChecksum getFileChecksum(Path f,
                                    long length)
                             throws IOException
```
    Get the checksum of a file, from the beginning of the file till the specific length.
    
    Parameters:
    
    f - The file path
    
    length - The length of the file range for checksum calculation
    
    Returns:
    
    The file checksum or null if checksums are not supported.
    
    Throws:
    
    IOException - IO failure
  - setVerifyChecksum
```
public void setVerifyChecksum(boolean verifyChecksum)
```
    Set the verify checksum flag. This is only applicable if the corresponding filesystem supports checksums. By default doesn't do anything.
    
    Parameters:
    
    verifyChecksum - Verify checksum flag
  - setWriteChecksum
```
public void setWriteChecksum(boolean writeChecksum)
```
    Set the write checksum flag. This is only applicable if the corresponding filesystem supports checksums. By default doesn't do anything.
    
    Parameters:
    
    writeChecksum - Write checksum flag
  - getStatus
```
public FsStatus getStatus()
                   throws IOException
```
    Returns a status object describing the use and capacity of the filesystem. If the filesystem has multiple partitions, the use and capacity of the root partition is reflected.
    
    Returns:
    
    a FsStatus object
    
    Throws:
    
    IOException - see specific implementation
  - getStatus
```
public FsStatus getStatus(Path p)
                   throws IOException
```
    Returns a status object describing the use and capacity of the filesystem. If the filesystem has multiple partitions, the use and capacity of the partition pointed to by the specified path is reflected.
    
    Parameters:
    
    p - Path for which status should be obtained. null means the default partition.
    
    Returns:
    
    a FsStatus object
    
    Throws:
    
    IOException - see specific implementation
  - setPermission
```
public void setPermission(Path p,
                          FsPermission permission)
                   throws IOException
```
    Set permission of a path.
    
    Parameters:
    
    p - The path
    
    permission - permission
    
    Throws:
    
    IOException - IO failure
  - setOwner
```
public void setOwner(Path p,
                     String username,
                     String groupname)
              throws IOException
```
    Set owner of a path (i.e. a file or a directory). The parameters username and groupname cannot both be null.
    
    Parameters:
    
    p - The path
    
    username - If it is null, the original username remains unchanged.
    
    groupname - If it is null, the original groupname remains unchanged.
    
    Throws:
    
    IOException - IO failure
  - setTimes
```
public void setTimes(Path p,
                     long mtime,
                     long atime)
              throws IOException
```
    Set access time of a file.
    
    Parameters:
    
    p - The path
    
    mtime - Set the modification time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set modification time.
    
    atime - Set the access time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set access time.
    
    Throws:
    
    IOException - IO failure
  - createSnapshot
```
public final Path createSnapshot(Path path)
                          throws IOException
```
    Create a snapshot with a default name.
    
    Parameters:
    
    path - The directory where snapshots will be taken.
    
    Returns:
    
    the snapshot path.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported
  - createSnapshot
```
public Path createSnapshot(Path path,
                           String snapshotName)
                    throws IOException
```
    Create a snapshot.
    
    Parameters:
    
    path - The directory where snapshots will be taken.
    
    snapshotName - The name of the snapshot
    
    Returns:
    
    the snapshot path.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported
  - renameSnapshot
```
public void renameSnapshot(Path path,
                           String snapshotOldName,
                           String snapshotNewName)
                    throws IOException
```
    Rename a snapshot.
    
    Parameters:
    
    path - The directory path where the snapshot was taken
    
    snapshotOldName - Old name of the snapshot
    
    snapshotNewName - New name of the snapshot
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - deleteSnapshot
```
public void deleteSnapshot(Path path,
                           String snapshotName)
                    throws IOException
```
    Delete a snapshot of a directory.
    
    Parameters:
    
    path - The directory that the to-be-deleted snapshot belongs to
    
    snapshotName - The name of the snapshot
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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, which must include entries for user, group, and others for compatibility with permission bits.
    
    Throws:
    
    IOException - if an ACL could not be modified
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getAclStatus
```
public AclStatus getAclStatus(Path path)
                       throws IOException
```
    Gets the ACL of a file or directory.
    
    Parameters:
    
    path - Path to get
    
    Returns:
    
    AclStatus describing the ACL of the file or directory
    
    Throws:
    
    IOException - if an ACL could not be read
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getXAttr
```
public byte[] getXAttr(Path path,
                       String name)
                throws IOException
```
    Get an xattr name and value 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getXAttrs
```
public Map<String,byte[]> getXAttrs(Path path)
                             throws IOException
```
    Get all of the xattr name/value pairs for a file or directory. Only those xattrs 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getXAttrs
```
public Map<String,byte[]> getXAttrs(Path path,
                                    List<String> names)
                             throws IOException
```
    Get all of the xattrs name/value pairs for a file or directory. Only those xattrs 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - listXAttrs
```
public List<String> listXAttrs(Path path)
                        throws IOException
```
    Get all of the xattr names for a file or directory. Only those xattr names 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:
    
    List of the XAttr names of the file or directory
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 src,
                             String policyName)
                      throws IOException
```
    Set the storage policy for a given file or directory.
    
    Parameters:
    
    src - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getStoragePolicy
```
public BlockStoragePolicySpi getStoragePolicy(Path src)
                                       throws IOException
```
    Query the effective storage policy ID for the given file or directory.
    
    Parameters:
    
    src - file or directory path.
    
    Returns:
    
    storage policy for give file.
    
    Throws:
    
    IOException - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - 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 - IO failure
    
    UnsupportedOperationException - if the operation is unsupported (default outcome).
  - getTrashRoot
```
public Path getTrashRoot(Path path)
```
    Get the root directory of Trash for current user when the path specified is deleted.
    
    Parameters:
    
    path - the trash root of the path to be determined.
    
    Returns:
    
    the default implementation returns /user/$USER/.Trash
  - getTrashRoots
```
public Collection<FileStatus> getTrashRoots(boolean allUsers)
```
    Get all the trash roots for current user or all users.
    
    Parameters:
    
    allUsers - return trash roots for all users if true.
    
    Returns:
    
    all the trash root directories. Default FileSystem returns .Trash under users' home directories if /user/$USER/.Trash exists.
  - hasPathCapability
```
public boolean hasPathCapability(Path path,
                                 String capability)
                          throws IOException
```
    The base FileSystem implementation generally has no knowledge of the capabilities of actual implementations. Unless it has a way to explicitly determine the capabilities, this method returns false. 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.
  - getFileSystemClass
```
public static Class<? extends FileSystem> getFileSystemClass(String scheme,
                                                             Configuration conf)
                                                      throws IOException
```
    Get the FileSystem implementation class of a filesystem. This triggers a scan and load of all FileSystem implementations listed as services and discovered via the ServiceLoader
    
    Parameters:
    
    scheme - URL scheme of FS
    
    conf - configuration: can be null, in which case the check for a filesystem binding declaration in the configuration is skipped.
    
    Returns:
    
    the filesystem
    
    Throws:
    
    UnsupportedFileSystemException - if there was no known implementation for the scheme.
    
    IOException - if the filesystem could not be loaded
  - getStatistics
```
@Deprecated
public static Map<String,org.apache.hadoop.fs.FileSystem.Statistics> getStatistics()
```
    Deprecated. use getGlobalStorageStatistics()
    
    Get the Map of Statistics object indexed by URI Scheme.
    
    Returns:
    
    a Map having a key as URI scheme and value as Statistics object
  - getAllStatistics
```
@Deprecated
public static List<org.apache.hadoop.fs.FileSystem.Statistics> getAllStatistics()
```
    Deprecated. use getGlobalStorageStatistics()
    
    Return the FileSystem classes that have Statistics.
  - getStatistics
```
@Deprecated
public static org.apache.hadoop.fs.FileSystem.Statistics getStatistics(String scheme,
                                                                                   Class<? extends FileSystem> cls)
```
    Deprecated. use getGlobalStorageStatistics()
    
    Get the statistics for a particular file system.
    
    Parameters:
    
    cls - the class to lookup
    
    Returns:
    
    a statistics object
  - clearStatistics
```
public static void clearStatistics()
```
    Reset all statistics for all file systems.
  - printStatistics
```
public static void printStatistics()
                            throws IOException
```
    Print all statistics for all file systems to System.out
    
    Throws:
    
    IOException
  - areSymlinksEnabled
```
public static boolean areSymlinksEnabled()
```
  - enableSymlinks
```
public static void enableSymlinks()
```
  - getStorageStatistics
```
public StorageStatistics getStorageStatistics()
```
    Get the StorageStatistics for this FileSystem object. These statistics are per-instance. They are not shared with any other FileSystem object.
    This is a default method which is intended to be overridden by subclasses. The default implementation returns an empty storage statistics object.
    
    Returns:
    
    The StorageStatistics for this FileSystem instance. Will never be null.
  - getGlobalStorageStatistics
```
public static GlobalStorageStatistics getGlobalStorageStatistics()
```
    Get the global storage statistics.
  - createFile
```
public FSDataOutputStreamBuilder createFile(Path path)
```
    Create a new FSDataOutputStreamBuilder for the file with path. Files are overwritten by default.
    
    Parameters:
    
    path - file path
    
    Returns:
    
    a FSDataOutputStreamBuilder object to build the file HADOOP-14384. Temporarily reduce the visibility of method before the builder interface becomes stable.
  - appendFile
```
public FSDataOutputStreamBuilder appendFile(Path path)
```
    Create a Builder to append a file.
    
    Parameters:
    
    path - file path.
    
    Returns:
    
    a FSDataOutputStreamBuilder to build file append request.

Class FileSystem

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.conf.Configured

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.hadoop.security.token.DelegationTokenIssuer

Field Detail

FS_DEFAULT_NAME_KEY

DEFAULT_FS

SHUTDOWN_HOOK_PRIORITY

TRASH_PREFIX

USER_HOME_PREFIX

statistics

Constructor Detail

FileSystem

Method Detail

get

get

getDefaultUri

setDefaultUri

setDefaultUri

initialize

getScheme

getUri

getCanonicalUri

canonicalizeUri

getDefaultPort

getFSofPath

getCanonicalServiceName

getName

getNamed

getLocal

get

newInstance

newInstance

newInstance

newInstanceLocal

closeAll

closeAllForUGI

makeQualified

create

mkdirs

checkPath

getFileBlockLocations

getFileBlockLocations

getServerDefaults

getServerDefaults

resolvePath

open

open

open

open

getPathHandle

createPathHandle

create

create

create

create

create

create

create

create

create

create

create

create

primitiveCreate

primitiveMkdir

primitiveMkdir

createNonRecursive

createNonRecursive

createNonRecursive

createNewFile

append

append

append

concat

getReplication

setReplication