alluxio.client.file

Class FileInStream

java.lang.Object

java.io.InputStream

alluxio.client.file.FileInStream

All Implemented Interfaces:

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

Direct Known Subclasses:

AlluxioFileInStream, AlluxioHdfsInputStream, LocalCacheFileInStream, UfsFileInStream

public abstract class FileInStream
extends InputStream
implements BoundedStream, PositionedReadable, Seekable, CanUnbuffer

A streaming API to read a file. This API represents a file as a stream of bytes and provides a collection of read() methods to access this stream of bytes. In addition, one can seek into a given offset of the stream to read.

Constructor Summary

Constructors

Constructor and Description
FileInStream()

Method Summary

Modifier and Type	Method and Description
int	read()
int	read(byte[] b)
int	read(byte[] b, int off, int len)
int	read(ByteBuffer buf) Reads up to buf.remaining() bytes into buf.
int	read(ByteBuffer byteBuffer, int off, int len) Reads up to len bytes of data from the input stream into the byte buffer.
void	unbuffer() Reduce the buffering.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.client.BoundedStream

remaining

Methods inherited from interface alluxio.client.PositionedReadable

positionedRead

Methods inherited from interface alluxio.Seekable

seek

Methods inherited from interface alluxio.Positioned

getPos

Constructor Detail

FileInStream

public FileInStream()

Method Detail

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

read

public int read(ByteBuffer buf)
         throws IOException

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.

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

read

public int read(ByteBuffer byteBuffer,
                int off,
                int len)
         throws IOException

Reads up to len bytes of data from the input stream into the byte buffer.

Parameters:

byteBuffer - the buffer into which the data is read

off - the start offset in the buffer at which the data is written

len - the maximum number of bytes to read

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached

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