Package org.apache.hadoop.net

Class SocketOutputStream

java.lang.Object

java.io.OutputStream

org.apache.hadoop.net.SocketOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable, Channel, WritableByteChannel

@LimitedPrivate({"HDFS","MapReduce"})
@Unstable
public class SocketOutputStream
extends OutputStream
implements WritableByteChannel

This implements an output stream that can have a timeout while writing. This sets non-blocking flag on the socket channel. So after creating this object , read() on Socket.getInputStream() and write() on Socket.getOutputStream() on the associated socket will throw llegalBlockingModeException. Please use SocketInputStream for reading.

Constructor Summary

Constructors

Constructor	Description
SocketOutputStream(Socket socket, long timeout)	Same as SocketOutputStream(socket.getChannel(), timeout): Create a new ouput stream with the given timeout.
SocketOutputStream(WritableByteChannel channel, long timeout)	Create a new ouput stream with the given timeout.

Method Summary

Modifier and Type	Method	Description
void	close()
WritableByteChannel	getChannel()
boolean	isOpen()
void	setTimeout(int timeoutMs)
void	transferToFully(FileChannel fileCh, long position, int count)	Call transferToFully(FileChannel, long, int, LongWritable, LongWritable) with null waitForWritableTime and transferToTime.
void	transferToFully(FileChannel fileCh, long position, int count, LongWritable waitForWritableTime, LongWritable transferToTime)	Transfers data from FileChannel using FileChannel.transferTo(long, long, WritableByteChannel).
void	waitForWritable()	waits for the underlying channel to be ready for writing.
void	write(byte[] b, int off, int len)
void	write(int b)
int	write(ByteBuffer src)

Methods inherited from class java.io.OutputStream

flush, nullOutputStream, write

Methods inherited from class java.lang.Object

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

Constructor Details

SocketOutputStream

public SocketOutputStream(WritableByteChannel channel,
 long timeout)
                   throws IOException

Create a new ouput stream with the given timeout. If the timeout is zero, it will be treated as infinite timeout. The socket's channel will be configured to be non-blocking.

Parameters:

channel - Channel for writing, should also be a SelectableChannel. The channel will be configured to be non-blocking.

timeout - timeout in milliseconds. must not be negative.

Throws:

IOException - raised on errors performing I/O.

SocketOutputStream

public SocketOutputStream(Socket socket,
 long timeout)
                   throws IOException

Same as SocketOutputStream(socket.getChannel(), timeout):

Create a new ouput stream with the given timeout. If the timeout is zero, it will be treated as infinite timeout. The socket's channel will be configured to be non-blocking.

Parameters:

socket - should have a channel associated with it.

timeout - timeout timeout in milliseconds. must not be negative.

Throws:

IOException - raised on errors performing I/O.

See Also:

• SocketOutputStream(WritableByteChannel, long)

Method Details

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

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

Overrides:

write in class OutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException

getChannel

public WritableByteChannel getChannel()

Returns:

Returns underlying channel used by this stream. This is useful in certain cases like channel for FileChannel.transferTo(long, long, WritableByteChannel)

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

write

public int write(ByteBuffer src)
          throws IOException

Specified by:

write in interface WritableByteChannel

Throws:

IOException

waitForWritable

public void waitForWritable()
                     throws IOException

waits for the underlying channel to be ready for writing. The timeout specified for this stream applies to this wait.

Throws:

SocketTimeoutException - if select on the channel times out.

IOException - if any other I/O error occurs.

transferToFully

public void transferToFully(FileChannel fileCh,
 long position,
 int count,
 LongWritable waitForWritableTime,
 LongWritable transferToTime)
                     throws IOException

Transfers data from FileChannel using FileChannel.transferTo(long, long, WritableByteChannel). Updates waitForWritableTime and transferToTime with the time spent blocked on the network and the time spent transferring data from disk to network respectively. Similar to readFully(), this waits till requested amount of data is transfered.

Parameters:

fileCh - FileChannel to transfer data from.

position - position within the channel where the transfer begins

count - number of bytes to transfer.

waitForWritableTime - nanoseconds spent waiting for the socket to become writable

transferToTime - nanoseconds spent transferring data

Throws:

EOFException - If end of input file is reached before requested number of bytes are transfered.

SocketTimeoutException - If this channel blocks transfer longer than timeout for this stream.

IOException - Includes any exception thrown by FileChannel.transferTo(long, long, WritableByteChannel).

transferToFully

public void transferToFully(FileChannel fileCh,
 long position,
 int count)
                     throws IOException

Call transferToFully(FileChannel, long, int, LongWritable, LongWritable) with null waitForWritableTime and transferToTime.

Parameters:

fileCh - input fileCh.

position - input position.

count - input count.

Throws:

IOException - raised on errors performing I/O.

setTimeout

public void setTimeout(int timeoutMs)