Package org.apache.sshd.common.channel

Class AbstractChannel

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.util.closeable.AbstractInnerCloseable

org.apache.sshd.common.channel.AbstractChannel

All Implemented Interfaces:

Closeable, AutoCloseable, Channel, AttributeRepository, AttributeStore, Channel, ChannelIdentifier, ChannelListenerManager, ChannelStreamWriterResolver, ChannelStreamWriterResolverManager, Closeable, PropertyResolver, SessionContextHolder, SessionHolder<Session>, ExecutorServiceCarrier

Direct Known Subclasses:

AbstractClientChannel, AbstractServerChannel

public abstract class AbstractChannel
extends AbstractInnerCloseable
implements Channel, ExecutorServiceCarrier

Provides common client/server channel functionality

Author:

Apache MINA SSHD Project

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	AbstractChannel.GracefulChannelCloseable
protected static enum	AbstractChannel.GracefulState
static interface	AbstractChannel.PacketValidator	A AbstractChannel.PacketValidator can validate packet lengths.

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

AbstractCloseable.State

Nested classes/interfaces inherited from interface org.apache.sshd.common.AttributeRepository

AttributeRepository.AttributeKey<T extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
protected final ChannelListener	channelListenerProxy
protected final Collection<ChannelListener>	channelListeners	Channel events listener
protected final AtomicBoolean	closeSignaled
static final AbstractChannel.PacketValidator	DEFAULT_PACKET_VALIDATOR	A default AbstractChannel.PacketValidator that enforces that the packet size is not greater than the maximum packet size of the channel's local window.
protected final AtomicBoolean	eofReceived
protected final AtomicBoolean	eofSent	Deprecated. since 2.10.1
protected final DefaultCloseFuture	gracefulFuture
protected AtomicReference<AbstractChannel.GracefulState>	gracefulState
protected final AtomicBoolean	initialized
static final IntUnaryOperator	RESPONSE_BUFFER_GROWTH_FACTOR	Default growth factor function used to resize response buffers
protected ConnectionService	service
protected final AtomicBoolean	unregisterSignaled

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

Fields inherited from interface org.apache.sshd.common.channel.Channel

CHANNEL_EXEC, CHANNEL_SHELL, CHANNEL_SUBSYSTEM

Fields inherited from interface org.apache.sshd.common.channel.throttle.ChannelStreamWriterResolver

NONE

Fields inherited from interface org.apache.sshd.common.PropertyResolver

EMPTY

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractChannel(boolean client)
protected	AbstractChannel(boolean client, Collection<? extends RequestHandler<Channel>> handlers)
protected	AbstractChannel(String discriminator, boolean client)
protected	AbstractChannel(String discriminator, boolean client, Collection<? extends RequestHandler<Channel>> handlers, CloseableExecutorService executorService)

Method Summary

Modifier and Type	Method	Description
void	addChannelListener(ChannelListener listener)	Add a channel listener
protected Date	addPendingRequest(String request, boolean wantReply)	Add a channel request to the tracked pending ones if reply is expected
void	addRequestHandler(RequestHandler<Channel> handler)
Collection<AttributeRepository.AttributeKey<?>>	attributeKeys()
void	clearAttributes()
<T> T	computeAttributeIfAbsent(AttributeRepository.AttributeKey<T> key, Function<? super AttributeRepository.AttributeKey<T>,? extends T> resolver)
protected void	configureWindow()
protected abstract void	doWriteData(byte[] data, int off, long len)
protected abstract void	doWriteExtendedData(byte[] data, int off, long len)
<T> T	getAttribute(AttributeRepository.AttributeKey<T> key)
int	getAttributesCount()
long	getChannelId()
ChannelListener	getChannelListenerProxy()
ChannelStreamWriterResolver	getChannelStreamWriterResolver()
CloseableExecutorService	getExecutorService()
protected Closeable	getInnerCloseable()
LocalWindow	getLocalWindow()
AbstractChannel.PacketValidator	getPacketValidator()	Retrieves the currently set AbstractChannel.PacketValidator.
PropertyResolver	getParentPropertyResolver()
Map<String,Object>	getProperties()
long	getRecipient()
RemoteWindow	getRemoteWindow()
List<RequestHandler<Channel>>	getRequestHandlers()
Session	getSession()
void	handleChannelRegistrationResult(ConnectionService service, Session session, long channelId, boolean registered)	Invoked after being successfully registered by the connection service - should throw a RuntimeException if not registered
protected void	handleChannelRequest(String req, boolean wantReply, Buffer buffer)
void	handleChannelUnregistration(ConnectionService service)	Called by the connection service to inform the channel that it has bee unregistered.
void	handleClose()	Invoked when SSH_MSG_CHANNEL_CLOSE received
void	handleData(Buffer buffer)	Invoked when SSH_MSG_CHANNEL_DATA received
void	handleEof()	Invoked when SSH_MSG_CHANNEL_EOF received
void	handleExtendedData(Buffer buffer)	Invoked when SSH_MSG_CHANNEL_EXTENDED_DATA received
void	handleFailure()	Invoked when SSH_MSG_CHANNEL_FAILURE received
protected RequestHandler.Result	handleInternalRequest(String req, boolean wantReply, Buffer buffer)	Called by handleUnknownChannelRequest(String, boolean, Buffer) in order to allow channel request handling if none of the registered handlers processed the request - last chance.
void	handleRequest(Buffer buffer)	Invoked when SSH_MSG_CHANNEL_REQUEST received
void	handleSuccess()	Invoked when SSH_MSG_CHANNEL_SUCCESS received
protected void	handleUnknownChannelRequest(String req, boolean wantReply, Buffer buffer)	Called when none of the register request handlers reported handling the request
void	handleWindowAdjust(Buffer buffer)	Invoked when SSH_MSG_CHANNEL_WINDOW_ADJUST received
void	init(ConnectionService service, Session session, long id)	Invoked when the local channel is initial created
protected void	invokeChannelSignaller(Invoker<ChannelListener,Void> invoker)
boolean	isEofSent()
boolean	isEofSignalled()
boolean	isInitialized()
protected boolean	mayWrite()
protected void	notifyStateChanged(String hint)
protected void	notifyStateChanged(ChannelListener listener, String hint)
protected void	preClose()
<T> T	removeAttribute(AttributeRepository.AttributeKey<T> key)
void	removeChannelListener(ChannelListener listener)	Remove a channel listener
protected Date	removePendingRequest(String request)	Removes a channel request from the tracked ones
void	removeRequestHandler(RequestHandler<Channel> handler)
ChannelStreamWriterResolver	resolveChannelStreamWriterResolver()
protected IoWriteFuture	sendEof()	Sends SSH_MSG_CHANNEL_EOF provided not already sent and current channel state allows it.
protected IoWriteFuture	sendResponse(Buffer buffer, String req, RequestHandler.Result result, boolean wantReply)
protected void	sendWindowAdjust(long len)
<T> T	setAttribute(AttributeRepository.AttributeKey<T> key, T value)
void	setChannelStreamWriterResolver(ChannelStreamWriterResolver resolver)
void	setPacketValidator(AbstractChannel.PacketValidator validator)	Sets a AbstractChannel.PacketValidator.
protected void	setRecipient(long recipient)
void	signalChannelClosed(Throwable reason)
protected void	signalChannelClosed(ChannelListener listener, Throwable reason)
protected void	signalChannelInitialized()
protected void	signalChannelInitialized(ChannelListener listener)
protected void	signalChannelOpenFailure(Throwable reason)
protected void	signalChannelOpenFailure(ChannelListener listener, Throwable reason)
protected void	signalChannelOpenSuccess()
protected void	signalChannelOpenSuccess(ChannelListener listener)
String	toString()
protected long	validateIncomingDataSize(int cmd, long len)
IoWriteFuture	writePacket(Buffer buffer)	Encode and send the given buffer.

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

doCloseGracefully, doCloseImmediately

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.channel.Channel

addRequestHandlers, handleOpenFailure, handleOpenSuccess, open, removeRequestHandlers, resolveAttribute

Methods inherited from interface org.apache.sshd.common.channel.throttle.ChannelStreamWriterResolverManager

resolveChannelStreamWriter

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

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

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

getBoolean, getBooleanProperty, getCharset, getInteger, getIntProperty, getLong, getLongProperty, getObject, getString, getStringProperty, isEmpty

Methods inherited from interface org.apache.sshd.common.session.SessionHolder

getSessionContext

Field Details

RESPONSE_BUFFER_GROWTH_FACTOR

public static final IntUnaryOperator RESPONSE_BUFFER_GROWTH_FACTOR

Default growth factor function used to resize response buffers

DEFAULT_PACKET_VALIDATOR

public static final AbstractChannel.PacketValidator DEFAULT_PACKET_VALIDATOR

A default AbstractChannel.PacketValidator that enforces that the packet size is not greater than the maximum packet size of the channel's local window.

service

protected ConnectionService service

initialized

protected final AtomicBoolean initialized

eofReceived

protected final AtomicBoolean eofReceived

eofSent

@Deprecated
protected final AtomicBoolean eofSent

Deprecated.

since 2.10.1

Obsolete and unused; present only for API backwards compatibility. Use isEofSent() to determine whether EOF is already sent on this channel, and sendEof() to send EOF. The latter will return null if EOF already was sent.

unregisterSignaled

protected final AtomicBoolean unregisterSignaled

closeSignaled

protected final AtomicBoolean closeSignaled

gracefulState

protected AtomicReference<AbstractChannel.GracefulState> gracefulState

gracefulFuture

protected final DefaultCloseFuture gracefulFuture

channelListeners

protected final Collection<ChannelListener> channelListeners

Channel events listener

channelListenerProxy

protected final ChannelListener channelListenerProxy

Constructor Details

AbstractChannel

protected AbstractChannel(boolean client)

AbstractChannel

protected AbstractChannel(boolean client,
 Collection<? extends RequestHandler<Channel>> handlers)

AbstractChannel

protected AbstractChannel(String discriminator,
 boolean client)

AbstractChannel

protected AbstractChannel(String discriminator,
 boolean client,
 Collection<? extends RequestHandler<Channel>> handlers,
 CloseableExecutorService executorService)

Method Details

getRequestHandlers

public List<RequestHandler<Channel>> getRequestHandlers()

Specified by:

getRequestHandlers in interface Channel

addRequestHandler

public void addRequestHandler(RequestHandler<Channel> handler)

Specified by:

addRequestHandler in interface Channel

removeRequestHandler

public void removeRequestHandler(RequestHandler<Channel> handler)

Specified by:

removeRequestHandler in interface Channel

getChannelId

public long getChannelId()

Specified by:

getChannelId in interface ChannelIdentifier

Returns:

Local channel UINT32 identifier

getRecipient

public long getRecipient()

Specified by:

getRecipient in interface Channel

Returns:

Remote channel UITN32 identifier

setRecipient

protected void setRecipient(long recipient)

getLocalWindow

public LocalWindow getLocalWindow()

Specified by:

getLocalWindow in interface Channel

getRemoteWindow

public RemoteWindow getRemoteWindow()

Specified by:

getRemoteWindow in interface Channel

getSession

public Session getSession()

Specified by:

getSession in interface SessionHolder<Session>

getParentPropertyResolver

public PropertyResolver getParentPropertyResolver()

Specified by:

getParentPropertyResolver in interface PropertyResolver

getExecutorService

public CloseableExecutorService getExecutorService()

Specified by:

getExecutorService in interface ExecutorServiceCarrier

getChannelStreamWriterResolver

public ChannelStreamWriterResolver getChannelStreamWriterResolver()

Specified by:

getChannelStreamWriterResolver in interface ChannelStreamWriterResolverManager

setChannelStreamWriterResolver

public void setChannelStreamWriterResolver(ChannelStreamWriterResolver resolver)

Specified by:

setChannelStreamWriterResolver in interface ChannelStreamWriterResolverManager

resolveChannelStreamWriterResolver

public ChannelStreamWriterResolver resolveChannelStreamWriterResolver()

Specified by:

resolveChannelStreamWriterResolver in interface ChannelStreamWriterResolverManager

addPendingRequest

protected Date addPendingRequest(String request,
 boolean wantReply)

Add a channel request to the tracked pending ones if reply is expected

Parameters:

request - The request type

wantReply - true if reply is expected

Returns:

The allocated Date timestamp - null if no reply is expected (in which case the request is not tracked)

Throws:

IllegalArgumentException - If the request is already being tracked

See Also:

• removePendingRequest(String)

removePendingRequest

protected Date removePendingRequest(String request)

Removes a channel request from the tracked ones

Parameters:

request - The request type

Returns:

The allocated Date timestamp - null if the specified request type is not being tracked or has not been added to the tracked ones to begin with

See Also:

• addPendingRequest(String, boolean)

handleRequest

public void handleRequest(Buffer buffer)
                   throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_REQUEST received

Specified by:

handleRequest in interface Channel

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleChannelRequest

protected void handleChannelRequest(String req,
 boolean wantReply,
 Buffer buffer)
                             throws IOException

Throws:

IOException

handleUnknownChannelRequest

protected void handleUnknownChannelRequest(String req,
 boolean wantReply,
 Buffer buffer)
                                    throws IOException

Called when none of the register request handlers reported handling the request

Parameters:

req - The request type

wantReply - Whether reply is requested

buffer - The Buffer containing extra request-specific data

Throws:

IOException - If failed to send the response (if needed)

See Also:

• handleInternalRequest(String, boolean, Buffer)

handleInternalRequest

protected RequestHandler.Result handleInternalRequest(String req,
 boolean wantReply,
 Buffer buffer)
                                               throws IOException

Called by handleUnknownChannelRequest(String, boolean, Buffer) in order to allow channel request handling if none of the registered handlers processed the request - last chance.

Parameters:

req - The request type

wantReply - Whether reply is requested

buffer - The Buffer containing extra request-specific data

Returns:

The handling result - if null or Unsupported and reply is required then a failure message will be sent

Throws:

IOException - If failed to process the request internally

sendResponse

protected IoWriteFuture sendResponse(Buffer buffer,
 String req,
 RequestHandler.Result result,
 boolean wantReply)
                              throws IOException

Throws:

IOException

init

public void init(ConnectionService service,
 Session session,
 long id)
          throws IOException

Description copied from interface: Channel

Invoked when the local channel is initial created

Specified by:

init in interface Channel

Parameters:

service - The ConnectionService through which the channel is initialized

session - The Session associated with the channel

id - The locally assigned channel identifier (UINT32 represented as a long)

Throws:

IOException - If failed to process the initialization

signalChannelInitialized

protected void signalChannelInitialized()
                                 throws IOException

Throws:

IOException

signalChannelInitialized

protected void signalChannelInitialized(ChannelListener listener)

signalChannelOpenSuccess

protected void signalChannelOpenSuccess()

signalChannelOpenSuccess

protected void signalChannelOpenSuccess(ChannelListener listener)

isInitialized

public boolean isInitialized()

Specified by:

isInitialized in interface Channel

Returns:

true if call to Channel.init(ConnectionService, Session, long) was successfully completed

handleChannelRegistrationResult

public void handleChannelRegistrationResult(ConnectionService service,
 Session session,
 long channelId,
 boolean registered)

Description copied from interface: Channel

Invoked after being successfully registered by the connection service - should throw a RuntimeException if not registered

Specified by:

handleChannelRegistrationResult in interface Channel

Parameters:

service - The ConnectionService through which the channel is registered

session - The Session associated with the channel

channelId - The locally assigned channel identifier (UINT32 represented as a long)

registered - Whether registration was successful or not

signalChannelOpenFailure

protected void signalChannelOpenFailure(Throwable reason)

signalChannelOpenFailure

protected void signalChannelOpenFailure(ChannelListener listener,
 Throwable reason)

notifyStateChanged

protected void notifyStateChanged(String hint)

notifyStateChanged

protected void notifyStateChanged(ChannelListener listener,
 String hint)

addChannelListener

public void addChannelListener(ChannelListener listener)

Description copied from interface: ChannelListenerManager

Add a channel listener

Specified by:

addChannelListener in interface ChannelListenerManager

Parameters:

listener - The ChannelListener to add - not null

removeChannelListener

public void removeChannelListener(ChannelListener listener)

Description copied from interface: ChannelListenerManager

Remove a channel listener

Specified by:

removeChannelListener in interface ChannelListenerManager

Parameters:

listener - The ChannelListener to remove

getChannelListenerProxy

public ChannelListener getChannelListenerProxy()

Specified by:

getChannelListenerProxy in interface ChannelListenerManager

Returns:

A (never null proxy ChannelListener that represents all the currently registered listeners. Any method invocation on the proxy is replicated to the currently registered listeners

handleClose

public void handleClose()
                 throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_CLOSE received

Specified by:

handleClose in interface Channel

Throws:

IOException - If failed to handle the message

getInnerCloseable

protected Closeable getInnerCloseable()

Specified by:

getInnerCloseable in class AbstractInnerCloseable

preClose

protected void preClose()

Overrides:

preClose in class AbstractCloseable

handleChannelUnregistration

public void handleChannelUnregistration(ConnectionService service)

Description copied from interface: Channel

Called by the connection service to inform the channel that it has bee unregistered.

Specified by:

handleChannelUnregistration in interface Channel

Parameters:

service - The ConnectionService through which the channel is unregistered

signalChannelClosed

public void signalChannelClosed(Throwable reason)

signalChannelClosed

protected void signalChannelClosed(ChannelListener listener,
 Throwable reason)

invokeChannelSignaller

protected void invokeChannelSignaller(Invoker<ChannelListener,Void> invoker)
                               throws Throwable

Throws:

Throwable

writePacket

public IoWriteFuture writePacket(Buffer buffer)
                          throws IOException

Description copied from interface: Channel

Encode and send the given buffer. Note: for session packets the buffer has to have 5 bytes free at the beginning to allow the encoding to take place. Also, the write position of the buffer has to be set to the position of the last byte to write.

Specified by:

writePacket in interface Channel

Parameters:

buffer - the buffer to encode and send. 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 packet has actually been sent

Throws:

IOException - if an error occurred when encoding or sending the packet

mayWrite

protected boolean mayWrite()

handleData

public void handleData(Buffer buffer)
                throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_DATA received

Specified by:

handleData in interface Channel

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleExtendedData

public void handleExtendedData(Buffer buffer)
                        throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_EXTENDED_DATA received

Specified by:

handleExtendedData in interface Channel

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

validateIncomingDataSize

protected long validateIncomingDataSize(int cmd,
 long len)
                                 throws IOException

Throws:

IOException

getPacketValidator

public AbstractChannel.PacketValidator getPacketValidator()

Retrieves the currently set AbstractChannel.PacketValidator.

Returns:

the validator, never null

setPacketValidator

public void setPacketValidator(AbstractChannel.PacketValidator validator)

Sets a AbstractChannel.PacketValidator.

Parameters:

validator - the validator to set, if null the DEFAULT_PACKET_VALIDATOR is set

handleEof

public void handleEof()
               throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_EOF received

Specified by:

handleEof in interface Channel

Throws:

IOException - If failed to handle the message

isEofSignalled

public boolean isEofSignalled()

Specified by:

isEofSignalled in interface Channel

Returns:

true if the peer signaled that it will not send any more data

See Also:

• RFC 4254 - section 5.3 - SSH_MSG_CHANNEL_EOF

handleWindowAdjust

public void handleWindowAdjust(Buffer buffer)
                        throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_WINDOW_ADJUST received

Specified by:

handleWindowAdjust in interface Channel

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleSuccess

public void handleSuccess()
                   throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_SUCCESS received

Specified by:

handleSuccess in interface Channel

Throws:

IOException - If failed to handle the message

handleFailure

public void handleFailure()
                   throws IOException

Description copied from interface: Channel

Invoked when SSH_MSG_CHANNEL_FAILURE received

Specified by:

handleFailure in interface Channel

Throws:

IOException - If failed to handle the message

doWriteData

protected abstract void doWriteData(byte[] data,
 int off,
 long len)
                             throws IOException

Throws:

IOException

doWriteExtendedData

protected abstract void doWriteExtendedData(byte[] data,
 int off,
 long len)
                                     throws IOException

Throws:

IOException

sendEof

protected IoWriteFuture sendEof()
                         throws IOException

Sends SSH_MSG_CHANNEL_EOF provided not already sent and current channel state allows it.

Returns:

The IoWriteFuture of the sent packet - null if message not sent due to channel state (or already sent)

Throws:

IOException - If failed to send the packet

isEofSent

public boolean isEofSent()

getProperties

public Map<String,Object> getProperties()

Specified by:

getProperties in interface PropertyResolver

getAttributesCount

public int getAttributesCount()

Specified by:

getAttributesCount in interface AttributeRepository

getAttribute

public <T> T getAttribute(AttributeRepository.AttributeKey<T> key)

Specified by:

getAttribute in interface AttributeRepository

attributeKeys

public Collection<AttributeRepository.AttributeKey<?>> attributeKeys()

Specified by:

attributeKeys in interface AttributeRepository

computeAttributeIfAbsent

public <T> T computeAttributeIfAbsent(AttributeRepository.AttributeKey<T> key,
 Function<? super AttributeRepository.AttributeKey<T>,? extends T> resolver)

Specified by:

computeAttributeIfAbsent in interface AttributeStore

setAttribute

public <T> T setAttribute(AttributeRepository.AttributeKey<T> key,
 T value)

Specified by:

setAttribute in interface AttributeStore

removeAttribute

public <T> T removeAttribute(AttributeRepository.AttributeKey<T> key)

Specified by:

removeAttribute in interface AttributeStore

clearAttributes

public void clearAttributes()

Specified by:

clearAttributes in interface AttributeStore

configureWindow

protected void configureWindow()

sendWindowAdjust

protected void sendWindowAdjust(long len)
                         throws IOException

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object