alluxio.hadoop

Class AlluxioHdfsInputStream

java.lang.Object

java.io.InputStream

alluxio.client.file.FileInStream

alluxio.hadoop.AlluxioHdfsInputStream

All Implemented Interfaces:

BoundedStream, CanUnbuffer, PositionedReadable, Positioned, Seekable, Closeable, AutoCloseable

public class AlluxioHdfsInputStream
extends FileInStream

A wrapper class to translate Hadoop FileSystem FSDataInputStream to Alluxio FileSystem FileInStream.

Constructor Summary

Constructors

Constructor and Description
AlluxioHdfsInputStream(org.apache.hadoop.fs.FSDataInputStream input)

Method Summary

Modifier and Type	Method and Description
int	available()
void	close()
long	getPos()
void	mark(int limit)
boolean	markSupported()
int	positionedRead(long position, byte[] buffer, int offset, int length) Reads up to the specified number of bytes, from a given position within a file, and return the number of bytes read.
int	read()
int	read(byte[] bytes)
int	read(byte[] bytes, int offset, int length)
int	read(ByteBuffer buf) Reads up to buf.remaining() bytes into buf.
long	remaining()
void	reset()
void	seek(long position) Moves the starting read position of the stream to the specified position which is relative to the start of the stream.
long	skip(long length)
void	unbuffer() Reduce the buffering.

Methods inherited from class alluxio.client.file.FileInStream

read

Methods inherited from class java.lang.Object

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

Constructor Detail

AlluxioHdfsInputStream

public AlluxioHdfsInputStream(org.apache.hadoop.fs.FSDataInputStream input)

Parameters:

input - Hadoop FileSystem FSDataInputStream

Method Detail

read

public int read(byte[] bytes)
         throws IOException

Overrides:

read in class FileInStream

Throws:

IOException

read

public int read(byte[] bytes,
                int offset,
                int length)
         throws IOException

Overrides:

read in class FileInStream

Throws:

IOException

read

public int read()
         throws IOException

Overrides:

read in class FileInStream

Throws:

IOException

read

public int read(ByteBuffer buf)
         throws IOException

Description copied from class: FileInStream

Reads up to buf.remaining() bytes into buf. Callers should use buf.limit(..) to control the size of the desired read.

After a successful call, buf.position() will be advanced by the number of bytes read and buf.limit() should be unchanged.

In the case of an exception, the values of buf.position() and buf.limit() are undefined, and callers should be prepared to recover from this eventually.

Implementations should treat 0-length requests as legitimate, and must not signal an error upon their receipt.

Overrides:

read in class FileInStream

Parameters:

buf - the ByteBuffer to receive the results of the read operation

Returns:

the number of bytes read, possibly zero, or -1 if reach end-of-stream

Throws:

IOException

skip

public long skip(long length)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

available

public int available()
              throws IOException

Overrides:

available in class InputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

mark

public void mark(int limit)

Overrides:

mark in class InputStream

reset

public void reset()
           throws IOException

Overrides:

reset in class InputStream

Throws:

IOException

markSupported

public boolean markSupported()

Overrides:

markSupported in class InputStream

seek

public void seek(long position)
          throws IOException

Description copied from interface: Seekable

Moves the starting read position of the stream to the specified position which is relative to the start of the stream. Seeking to a position before the current read position is supported.

Parameters:

position - the position to seek to, it must be between 0 and the end of the stream - 1

Throws:

IOException

getPos

public long getPos()
            throws IOException

Returns:

the current position

Throws:

IOException

remaining

public long remaining()

Returns:

the remaining number of bytes left in the stream, starting at the current position

positionedRead

public int positionedRead(long position,
                          byte[] buffer,
                          int offset,
                          int length)
                   throws IOException

Description copied from interface: PositionedReadable

Reads up to the specified number of bytes, from a given position within a file, and return the number of bytes read. This does not change the current offset of a file, and is thread-safe. Not all implementations meet the thread safety requirement. According to the documentation of the PositionedReadable interface in Hadoop, those that do not meet the requirement cannot be used as a backing store for some applications, such as Apache HBase. All implementations of this interface in Alluxio must meet the thread safety requirement.

Parameters:

position - position within file

buffer - destination buffer

offset - offset in the buffer

length - number of bytes to read

Returns:

actual number of bytes read; -1 means "EOF";

Throws:

IOException

unbuffer

public void unbuffer()

Description copied from interface: CanUnbuffer

Reduce the buffering. This will also free sockets and file descriptors held by the stream, if possible.

Specified by:

unbuffer in interface CanUnbuffer

Overrides:

unbuffer in class FileInStream