Package org.apache.sshd.common.channel

Class ChannelAsyncOutputStream

java.lang.Object

org.apache.sshd.common.util.logging.AbstractLoggingBean

org.apache.sshd.common.util.closeable.IoBaseCloseable

org.apache.sshd.common.util.closeable.AbstractCloseable

org.apache.sshd.common.channel.ChannelAsyncOutputStream

All Implemented Interfaces:

Closeable, AutoCloseable, Channel, ChannelHolder, Closeable, IoOutputStream

public class ChannelAsyncOutputStream
extends AbstractCloseable
implements IoOutputStream, ChannelHolder

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	ChannelAsyncOutputStream.BufferedFuture	Marker type to avoid repeated buffering in writePacket(IoWriteFutureImpl, boolean).
protected static class	ChannelAsyncOutputStream.WriteState	Collects state variables; access is always synchronized on the single instance per stream.

Nested classes/interfaces inherited from class org.apache.sshd.common.util.closeable.AbstractCloseable

AbstractCloseable.State

Field Summary

Fields

Modifier and Type	Field	Description
protected ChannelAsyncOutputStream.WriteState	writeState	Encapsulates the state of the current write operation.

Fields inherited from class org.apache.sshd.common.util.closeable.AbstractCloseable

closeFuture, futureLock, state

Fields inherited from class org.apache.sshd.common.util.logging.AbstractLoggingBean

log

Constructor Summary

Constructors

Constructor	Description
ChannelAsyncOutputStream(Channel channel, byte cmd)
ChannelAsyncOutputStream(Channel channel, byte cmd, boolean sendChunkIfRemoteWindowIsSmallerThanPacketSize)

Method Summary

Modifier and Type	Method	Description
protected Buffer	createSendBuffer(Buffer buffer, Channel channel, long length)
protected CloseFuture	doCloseGracefully()
protected void	doCloseImmediately()
protected void	doWriteIfPossible(boolean resume)
Channel	getChannel()
byte	getCommandType()
boolean	isSendChunkIfRemoteWindowIsSmallerThanPacketSize()
void	onWindowExpanded()
protected void	onWritten(IoWriteFutureImpl future, int total, long length, IoWriteFuture f)
protected void	preClose()
void	setSendChunkIfRemoteWindowIsSmallerThanPacketSize(boolean sendChunkIfRemoteWindowIsSmallerThanPacketSize)
protected void	shutdown()
protected void	terminateFuture(IoWriteFutureImpl future)
String	toString()
IoWriteFuture	writeBuffer(Buffer buffer)	This write operation is asynchronous: if there is not enough window space, it may keep the write pending or write only part of the buffer and keep the rest pending.
protected IoWriteFutureImpl	writePacket(IoWriteFutureImpl future, boolean resume)	Try to write as much of the current buffer as possible.

Methods inherited from class org.apache.sshd.common.util.closeable.AbstractCloseable

addCloseFutureListener, builder, close, getFutureLock, isClosed, isClosing, removeCloseFutureListener

Methods inherited from class org.apache.sshd.common.util.logging.AbstractLoggingBean

debug, debug, debug, debug, debug, error, error, error, error, error, getSimplifiedLogger, info, info, warn, warn, warn, warn, warn, warn, warn, warn

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.sshd.common.Closeable

addCloseFutureListener, close, close, isClosed, isClosing, isOpen, removeCloseFutureListener

Field Detail

writeState

protected final ChannelAsyncOutputStream.WriteState writeState

Encapsulates the state of the current write operation. Access is always under lock (on writeState's monitor), the lock is held only shortly and never while writing.

Constructor Detail

ChannelAsyncOutputStream

public ChannelAsyncOutputStream(Channel channel,
                                byte cmd)

Parameters:

channel - The Channel through which the stream is communicating

cmd - Either SSH_MSG_CHANNEL_DATA or SSH_MSG_CHANNEL_EXTENDED_DATA indicating the output stream type

ChannelAsyncOutputStream

public ChannelAsyncOutputStream(Channel channel,
                                byte cmd,
                                boolean sendChunkIfRemoteWindowIsSmallerThanPacketSize)

Parameters:

channel - The Channel through which the stream is communicating

cmd - Either SSH_MSG_CHANNEL_DATA or SSH_MSG_CHANNEL_EXTENDED_DATA indicating the output stream type

sendChunkIfRemoteWindowIsSmallerThanPacketSize - Determines the chunking behaviour, if the remote window size is smaller than the packet size. Can be used to establish compatibility with certain clients, that wait until the window size is 0 before adjusting it.

See Also:

SSHD-1123

Method Detail

getChannel

public Channel getChannel()

Specified by:

getChannel in interface ChannelHolder

Returns:

The associated Channel instance

getCommandType

public byte getCommandType()

Returns:

Either SSH_MSG_CHANNEL_DATA or SSH_MSG_CHANNEL_EXTENDED_DATA indicating the output stream type

writeBuffer

public IoWriteFuture writeBuffer(Buffer buffer)
                          throws IOException

This write operation is asynchronous: if there is not enough window space, it may keep the write pending or write only part of the buffer and keep the rest pending. Concurrent writes are not allowed and will throw a WritePendingException. Any subsequent write must occur only once the returned future is fulfilled; for instance triggered via a listener on the returned future. Try to avoid doing a subsequent write directly in a future listener, though; doing so may lead to deep chains of nested listener calls with deep stack traces, and may ultimately lead to a stack overflow.

Specified by:

writeBuffer in interface IoOutputStream

Throws:

WritePendingException - if a concurrent write is attempted

IOException

preClose

protected void preClose()

Overrides:

preClose in class AbstractCloseable

doCloseImmediately

protected void doCloseImmediately()

Overrides:

doCloseImmediately in class AbstractCloseable

shutdown

protected void shutdown()

terminateFuture

protected void terminateFuture(IoWriteFutureImpl future)

doCloseGracefully

protected CloseFuture doCloseGracefully()

Overrides:

doCloseGracefully in class AbstractCloseable

onWindowExpanded

public void onWindowExpanded()
                      throws IOException

Throws:

IOException

doWriteIfPossible

protected void doWriteIfPossible(boolean resume)

writePacket

protected IoWriteFutureImpl writePacket(IoWriteFutureImpl future,
                                        boolean resume)

Try to write as much of the current buffer as possible. If the buffer is larger than the packet size split it in packets, writing one after the other by chaining futures. If there is not enough window space, stop writing. Writing will be resumed once the window has been enlarged again.

Parameters:

future - IoWriteFutureImpl for the current write

resume - whether being called in response to a remote window adjustment

Returns:

null if all written, or if the rest will be written via a future listener. Otherwise a future for the remaining writes.

onWritten

protected void onWritten(IoWriteFutureImpl future,
                         int total,
                         long length,
                         IoWriteFuture f)

createSendBuffer

protected Buffer createSendBuffer(Buffer buffer,
                                  Channel channel,
                                  long length)

toString

public String toString()

Overrides:

toString in class Object

isSendChunkIfRemoteWindowIsSmallerThanPacketSize

public boolean isSendChunkIfRemoteWindowIsSmallerThanPacketSize()

setSendChunkIfRemoteWindowIsSmallerThanPacketSize

public void setSendChunkIfRemoteWindowIsSmallerThanPacketSize(boolean sendChunkIfRemoteWindowIsSmallerThanPacketSize)