Package org.apache.hadoop.fs

Class FileSystemLinkResolver<T>

java.lang.Object

org.apache.hadoop.fs.FileSystemLinkResolver<T>

@Private
@Evolving
public abstract class FileSystemLinkResolver<T>
extends Object

FileSystem-specific class used to operate on and resolve symlinks in a path. Operation can potentially span multiple FileSystems.

See Also:

• FSLinkResolver

Constructor Summary

Constructors

Constructor	Description
FileSystemLinkResolver()

Method Summary

Modifier and Type	Method	Description
abstract T	doCall(Path p)	FileSystem subclass-specific implementation of superclass method.
abstract T	next(FileSystem fs, Path p)	Calls the abstract FileSystem call equivalent to the specialized subclass implementation in doCall(Path).
T	resolve(FileSystem filesys, Path path)	Attempt calling overridden doCall(Path) method with specified FileSystem and Path.

Methods inherited from class java.lang.Object

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

Constructor Details

FileSystemLinkResolver

public FileSystemLinkResolver()

Method Details

doCall

public abstract T doCall(Path p)
                  throws IOException,
UnresolvedLinkException

FileSystem subclass-specific implementation of superclass method. Overridden on instantiation to perform the actual method call, which throws an UnresolvedLinkException if called on an unresolved Path.

Parameters:

p - Path on which to perform an operation

Returns:

Generic type returned by operation

Throws:

IOException - raised on errors performing I/O.

UnresolvedLinkException - unresolved link exception.

next

public abstract T next(FileSystem fs,
 Path p)
                throws IOException

Calls the abstract FileSystem call equivalent to the specialized subclass implementation in doCall(Path). This is used when retrying the call with a newly resolved Path and corresponding new FileSystem.

Parameters:

fs - FileSystem with which to retry call

p - Resolved Target of path

Returns:

Generic type determined by implementation

Throws:

IOException - raised on errors performing I/O.

resolve

public T resolve(FileSystem filesys,
 Path path)
          throws IOException

Attempt calling overridden doCall(Path) method with specified FileSystem and Path. If the call fails with an UnresolvedLinkException, it will try to resolve the path and retry the call by calling next(FileSystem, Path).

Parameters:

filesys - FileSystem with which to try call

path - Path with which to try call

Returns:

Generic type determined by implementation

Throws:

IOException - raised on errors performing I/O.