org.apache.hadoop.io.nativeio

Class NativeIO

java.lang.Object

org.apache.hadoop.io.nativeio.NativeIO

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class NativeIO
extends Object

JNI wrappers for various native IO-related calls not available in Java. These functions should generally be used alongside a fallback to another more portable mechanism.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NativeIO.POSIX
static class	NativeIO.Windows

Constructor Summary

Constructors

Constructor and Description
NativeIO()

Method Summary

Methods

Modifier and Type	Method and Description
static FileOutputStream	getCreateForWriteFileOutputStream(File f, int permissions) Create the specified File for write access, ensuring that it does not exist.
static String	getOwner(FileDescriptor fd)
static FileInputStream	getShareDeleteFileInputStream(File f) Create a FileInputStream that shares delete permission on the file opened, i.e.
static FileInputStream	getShareDeleteFileInputStream(File f, long seekOffset) Create a FileInputStream that shares delete permission on the file opened at a given offset, i.e.
static boolean	isAvailable() Return true if the JNI-based native IO extensions are available.
static void	renameTo(File src, File dst) A version of renameTo that throws a descriptive exception when it fails.

Methods inherited from class java.lang.Object

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

Constructor Detail

NativeIO

public NativeIO()

Method Detail

isAvailable

public static boolean isAvailable()

Return true if the JNI-based native IO extensions are available.

getOwner

public static String getOwner(FileDescriptor fd)
                       throws IOException

Throws:

IOException

getShareDeleteFileInputStream

public static FileInputStream getShareDeleteFileInputStream(File f)
                                                     throws IOException

Create a FileInputStream that shares delete permission on the file opened, i.e. other process can delete the file the FileInputStream is reading. Only Windows implementation uses the native interface.

Throws:

IOException

getShareDeleteFileInputStream

public static FileInputStream getShareDeleteFileInputStream(File f,
                                            long seekOffset)
                                                     throws IOException

Create a FileInputStream that shares delete permission on the file opened at a given offset, i.e. other process can delete the file the FileInputStream is reading. Only Windows implementation uses the native interface.

Throws:

IOException

getCreateForWriteFileOutputStream

public static FileOutputStream getCreateForWriteFileOutputStream(File f,
                                                 int permissions)
                                                          throws IOException

Create the specified File for write access, ensuring that it does not exist.

Parameters:

f - the file that we want to create

permissions - we want to have on the file (if security is enabled)

Throws:

SecureIOUtils.AlreadyExistsException - if the file already exists

IOException - if any other error occurred

renameTo

public static void renameTo(File src,
            File dst)
                     throws IOException

A version of renameTo that throws a descriptive exception when it fails.

Parameters:

src - The source path

dst - The destination path

Throws:

NativeIOException - On failure.

IOException