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, IoOutputStream

public class ChannelAsyncOutputStream
extends AbstractCloseable
implements IoOutputStream, ChannelHolder

Nested Class Summary

Nested Classes

Modifier and Type	Class and 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 and 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 and Description
ChannelAsyncOutputStream(Channel channel, byte cmd)

Method Summary

Modifier and Type	Method and Description
protected Buffer	createSendBuffer(Buffer buffer, Channel channel, int length)
protected CloseFuture	doCloseGracefully()
protected void	doCloseImmediately() doCloseImmediately is called once and only once with state == Immediate
protected void	doWriteIfPossible(boolean resume)
Channel	getChannel()
byte	getCommandType()
void	onWindowExpanded()
protected void	onWritten(IoWriteFutureImpl future, int total, int length, IoWriteFuture f)
protected void	preClose() preClose is guaranteed to be called before doCloseGracefully or doCloseImmediately.
protected void	shutdown()
protected void	terminateFuture(IoWriteFutureImpl future)
String	toString()
IoWriteFuture	writeBuffer(Buffer buffer) Write the given buffer.
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, close, getMaxCloseWaitTime, 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

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

Write the given 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. 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

Parameters:

buffer - the data to write. NOTE: the buffer must not be touched until the returned write future is completed.

Returns:

An IoWriteFuture that can be used to check when the data has actually been written.

Throws:

WritePendingException - if a concurrent write is attempted

IOException - if an error occurred when writing the data

preClose

protected void preClose()

Description copied from class: AbstractCloseable

preClose is guaranteed to be called before doCloseGracefully or doCloseImmediately. When preClose() is called, isClosing() == true

Overrides:

preClose in class AbstractCloseable

doCloseImmediately

protected void doCloseImmediately()

Description copied from class: AbstractCloseable

doCloseImmediately is called once and only once with state == Immediate

Overriding methods should always call the base implementation. It may be called concurrently while preClose() or doCloseGracefully is executing

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,
                         int length,
                         IoWriteFuture f)

createSendBuffer

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

toString

public String toString()

Overrides:

toString in class Object