org.apache.hadoop.io.nativeio
Class NativeIO

java.lang.Object
  org.apache.hadoop.io.nativeio.NativeIO

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

static class

NativeIO.Stat Result type of the fstat call

Field Summary

static int	O_APPEND
static int	O_ASYNC
static int	O_CREAT
static int	O_EXCL
static int	O_FSYNC
static int	O_NDELAY
static int	O_NOCTTY
static int	O_NONBLOCK
static int	O_RDONLY
static int	O_RDWR
static int	O_SYNC
static int	O_TRUNC
static int	O_WRONLY
static int	POSIX_FADV_DONTNEED
static int	POSIX_FADV_NOREUSE
static int	POSIX_FADV_NORMAL
static int	POSIX_FADV_RANDOM
static int	POSIX_FADV_SEQUENTIAL
static int	POSIX_FADV_WILLNEED
static int	SYNC_FILE_RANGE_WAIT_AFTER
static int	SYNC_FILE_RANGE_WAIT_BEFORE
static int	SYNC_FILE_RANGE_WRITE

Constructor Summary

NativeIO()

Method Summary

static void	chmod(String path, int mode) Wrapper around chmod(2)
static NativeIO.Stat	fstat(FileDescriptor fd) Wrapper around fstat(2)
static String	getOwner(FileDescriptor fd)
static boolean	isAvailable() Return true if the JNI-based native IO extensions are available.
static FileDescriptor	open(String path, int flags, int mode) Wrapper around open(2)
static void	posixFadviseIfPossible(FileDescriptor fd, long offset, long len, int flags) Call posix_fadvise on the given file descriptor.
static void	syncFileRangeIfPossible(FileDescriptor fd, long offset, long nbytes, int flags) Call sync_file_range on the given file descriptor.

Methods inherited from class java.lang.Object

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

Field Detail

O_RDONLY

public static final int O_RDONLY

See Also:

Constant Field Values

O_WRONLY

public static final int O_WRONLY

See Also:

Constant Field Values

O_RDWR

public static final int O_RDWR

See Also:

Constant Field Values

O_CREAT

public static final int O_CREAT

See Also:

Constant Field Values

O_EXCL

public static final int O_EXCL

See Also:

Constant Field Values

O_NOCTTY

public static final int O_NOCTTY

See Also:

Constant Field Values

O_TRUNC

public static final int O_TRUNC

See Also:

Constant Field Values

O_APPEND

public static final int O_APPEND

See Also:

Constant Field Values

O_NONBLOCK

public static final int O_NONBLOCK

See Also:

Constant Field Values

O_SYNC

public static final int O_SYNC

See Also:

Constant Field Values

O_ASYNC

public static final int O_ASYNC

See Also:

Constant Field Values

O_FSYNC

public static final int O_FSYNC

See Also:

Constant Field Values

O_NDELAY

public static final int O_NDELAY

See Also:

Constant Field Values

POSIX_FADV_NORMAL

public static final int POSIX_FADV_NORMAL

See Also:

Constant Field Values

POSIX_FADV_RANDOM

public static final int POSIX_FADV_RANDOM

See Also:

Constant Field Values

POSIX_FADV_SEQUENTIAL

public static final int POSIX_FADV_SEQUENTIAL

See Also:

Constant Field Values

POSIX_FADV_WILLNEED

public static final int POSIX_FADV_WILLNEED

See Also:

Constant Field Values

POSIX_FADV_DONTNEED

public static final int POSIX_FADV_DONTNEED

See Also:

Constant Field Values

POSIX_FADV_NOREUSE

public static final int POSIX_FADV_NOREUSE

See Also:

Constant Field Values

SYNC_FILE_RANGE_WAIT_BEFORE

public static final int SYNC_FILE_RANGE_WAIT_BEFORE

See Also:

Constant Field Values

SYNC_FILE_RANGE_WRITE

public static final int SYNC_FILE_RANGE_WRITE

See Also:

Constant Field Values

SYNC_FILE_RANGE_WAIT_AFTER

public static final int SYNC_FILE_RANGE_WAIT_AFTER

See Also:

Constant Field Values

Constructor Detail

NativeIO

public NativeIO()

Method Detail

isAvailable

public static boolean isAvailable()

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

open

public static FileDescriptor open(String path,
                                  int flags,
                                  int mode)
                           throws IOException

Wrapper around open(2)

Throws:

IOException

fstat

public static NativeIO.Stat fstat(FileDescriptor fd)
                           throws IOException

Wrapper around fstat(2)

Throws:

IOException

chmod

public static void chmod(String path,
                         int mode)
                  throws IOException

Wrapper around chmod(2)

Throws:

IOException

posixFadviseIfPossible

public static void posixFadviseIfPossible(FileDescriptor fd,
                                          long offset,
                                          long len,
                                          int flags)
                                   throws NativeIOException

Call posix_fadvise on the given file descriptor. See the manpage for this syscall for more information. On systems where this call is not available, does nothing.

Throws:

NativeIOException - if there is an error with the syscall

syncFileRangeIfPossible

public static void syncFileRangeIfPossible(FileDescriptor fd,
                                           long offset,
                                           long nbytes,
                                           int flags)
                                    throws NativeIOException

Call sync_file_range on the given file descriptor. See the manpage for this syscall for more information. On systems where this call is not available, does nothing.

Throws:

NativeIOException - if there is an error with the syscall

getOwner

public static String getOwner(FileDescriptor fd)
                       throws IOException

Throws:

IOException