org.apache.hadoop.fs

Class FSInputStream

java.lang.Object

java.io.InputStream

org.apache.hadoop.fs.FSInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, PositionedReadable, Seekable

Direct Known Subclasses:

ByteRangeInputStream, DFSInputStream, FSInputChecker, FTPInputStream

@InterfaceAudience.LimitedPrivate(value="HDFS")
@InterfaceStability.Unstable
public abstract class FSInputStream
extends InputStream
implements Seekable, PositionedReadable

FSInputStream is a generic old InputStream with a little bit of RAF-style seek ability.

Constructor Summary

Constructors

Constructor and Description
FSInputStream()

Method Summary

Methods

Modifier and Type	Method and Description
abstract long	getPos() Return the current offset from the start of the file
int	read(long position, byte[] buffer, int offset, int length) Read upto the specified number of bytes, from a given position within a file, and return the number of bytes read.
void	readFully(long position, byte[] buffer) Read number of bytes equal to the length of the buffer, from a given position within a file.
void	readFully(long position, byte[] buffer, int offset, int length) Read the specified number of bytes, from a given position within a file.
abstract void	seek(long pos) Seek to the given offset from the start of the file.
abstract boolean	seekToNewSource(long targetPos) Seeks a different copy of the data.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

FSInputStream

public FSInputStream()

Method Detail

seek

public abstract void seek(long pos)
                   throws IOException

Seek to the given offset from the start of the file. The next read() will be from that location. Can't seek past the end of the file.

Specified by:

seek in interface Seekable

Throws:

IOException

getPos

public abstract long getPos()
                     throws IOException

Return the current offset from the start of the file

Specified by:

getPos in interface Seekable

Throws:

IOException

seekToNewSource

public abstract boolean seekToNewSource(long targetPos)
                                 throws IOException

Seeks a different copy of the data. Returns true if found a new source, false otherwise.

Specified by:

seekToNewSource in interface Seekable

Throws:

IOException

read

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

Description copied from interface: PositionedReadable

Read upto 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.

Specified by:

read in interface PositionedReadable

Throws:

IOException

readFully

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

Description copied from interface: PositionedReadable

Read the specified number of bytes, from a given position within a file. This does not change the current offset of a file, and is thread-safe.

Specified by:

readFully in interface PositionedReadable

Throws:

IOException

readFully

public void readFully(long position,
             byte[] buffer)
               throws IOException

Description copied from interface: PositionedReadable

Read number of bytes equal to the length of the buffer, from a given position within a file. This does not change the current offset of a file, and is thread-safe.

Specified by:

readFully in interface PositionedReadable

Throws:

IOException