alluxio.underfs.hdfs

Class HdfsPositionedUnderFileInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

alluxio.underfs.SeekableUnderFileInputStream

alluxio.underfs.hdfs.HdfsPositionedUnderFileInputStream

All Implemented Interfaces:

Positioned, PositionReader, Seekable, Closeable, AutoCloseable

public class HdfsPositionedUnderFileInputStream
extends SeekableUnderFileInputStream
implements PositionReader

The input stream of HDFS as under filesystem. This input stream has two mode of operations. Under sequential mode, it uses the read api and can take advantage of underlying stream's buffering. Under random read mode, it uses the positionedRead FSDataInputStream API. This stream can be cached for reuse.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Method Summary

Modifier and Type	Method and Description
int	available()
void	close() Closes the positon reader and do cleanup job if any.
long	getPos()
boolean	markSupported()
int	read()
int	read(byte[] b)
int	read(byte[] buffer, int offset, int length) If there has been a number of sequential reads in a row, we move to regular buffered reads.
int	readInternal(long position, ReadTargetBuffer buffer, int length)
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 n)

Methods inherited from class java.io.FilterInputStream

mark, reset

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.PositionReader

read, read, read, read, read

Method Detail

available

public int available()
              throws IOException

Overrides:

available in class FilterInputStream

Throws:

IOException

getPos

public long getPos()

Specified by:

getPos in interface Positioned

Returns:

the current position

read

public int read()

Overrides:

read in class FilterInputStream

read

public int read(byte[] b)

Overrides:

read in class FilterInputStream

read

public int read(byte[] buffer,
                int offset,
                int length)

If there has been a number of sequential reads in a row, we move to regular buffered reads.

Overrides:

read in class FilterInputStream

seek

public void seek(long position)

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.

Specified by:

seek in interface Seekable

Parameters:

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

skip

public long skip(long n)

Overrides:

skip in class FilterInputStream

markSupported

public boolean markSupported()

Overrides:

markSupported in class FilterInputStream

readInternal

public int readInternal(long position,
                        ReadTargetBuffer buffer,
                        int length)
                 throws IOException

Specified by:

readInternal in interface PositionReader

Parameters:

position - position of the file to start reading data

buffer - target byte buffer

length - bytes to read

Returns:

bytes read, or -1 none of data is read

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: PositionReader

Closes the positon reader and do cleanup job if any.

Specified by:

close in interface PositionReader

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class FilterInputStream

Throws:

IOException