@Exported public abstract class SctpChannel extends AbstractSelectableChannel
An SCTP channel can only control one SCTP association.
An SCTPChannel
is created by invoking one of the
open
methods of this class. A newly-created channel is open but
not yet connected, that is, there is no association setup with a remote peer.
An attempt to invoke an I/O operation upon an unconnected
channel will cause a NotYetConnectedException
to be
thrown. An association can be setup by connecting the channel using one of
its connect
methods. Once connected, the channel remains
connected until it is closed. Whether or not a channel is connected may be
determined by invoking getRemoteAddresses
.
SCTP channels support non-blocking connection: A
channel may be created and the process of establishing the link to
the remote socket may be initiated via the connect
method
for later completion by the finishConnect
method.
Whether or not a connection operation is in progress may be determined by
invoking the isConnectionPending
method.
Socket options are configured using the
setOption
method. An SCTP
channel support the following options:
Additional (implementation specific) options may also be supported. The list of options supported is obtained by invoking the
Option Name Description SCTP_DISABLE_FRAGMENTS
Enables or disables message fragmentation SCTP_EXPLICIT_COMPLETE
Enables or disables explicit message completion SCTP_FRAGMENT_INTERLEAVE
Controls how the presentation of messages occur for the message receiver SCTP_INIT_MAXSTREAMS
The maximum number of streams requested by the local endpoint during association initialization SCTP_NODELAY
Enables or disable a Nagle-like algorithm SCTP_PRIMARY_ADDR
Requests that the local SCTP stack use the given peer address as the association primary SCTP_SET_PEER_PRIMARY_ADDR
Requests that the peer mark the enclosed address as the association primary SO_SNDBUF
The size of the socket send buffer SO_RCVBUF
The size of the socket receive buffer SO_LINGER
Linger on close if data is present (when configured in blocking mode only)
supportedOptions
method.
SCTP channels are safe for use by multiple concurrent threads.
They support concurrent reading and writing, though at most one thread may be
reading and at most one thread may be writing at any given time. The
connect
and finishConnect
methods are mutually synchronized against each other, and
an attempt to initiate a send or receive operation while an invocation of one
of these methods is in progress will block until that invocation is complete.
Modifier | Constructor and Description |
---|---|
protected |
SctpChannel(SelectorProvider provider)
Initializes a new instance of this class.
|
Modifier and Type | Method and Description |
---|---|
abstract Association |
association()
Returns the association on this channel's socket.
|
abstract SctpChannel |
bind(SocketAddress local)
Binds the channel's socket to a local address.
|
abstract SctpChannel |
bindAddress(InetAddress address)
Adds the given address to the bound addresses for the channel's
socket.
|
abstract boolean |
connect(SocketAddress remote)
Connects this channel's socket.
|
abstract boolean |
connect(SocketAddress remote,
int maxOutStreams,
int maxInStreams)
Connects this channel's socket.
|
abstract boolean |
finishConnect()
Finishes the process of connecting an SCTP channel.
|
abstract Set<SocketAddress> |
getAllLocalAddresses()
Returns all of the socket addresses to which this channel's socket is
bound.
|
abstract <T> T |
getOption(SctpSocketOption<T> name)
Returns the value of a socket option.
|
abstract Set<SocketAddress> |
getRemoteAddresses()
Returns all of the remote addresses to which this channel's socket
is connected.
|
abstract boolean |
isConnectionPending()
Tells whether or not a connection operation is in progress on this channel.
|
static SctpChannel |
open()
Opens an SCTP channel.
|
static SctpChannel |
open(SocketAddress remote,
int maxOutStreams,
int maxInStreams)
Opens an SCTP channel and connects it to a remote address.
|
abstract <T> MessageInfo |
receive(ByteBuffer dst,
T attachment,
NotificationHandler<T> handler)
Receives a message into the given buffer and/or handles a notification.
|
abstract int |
send(ByteBuffer src,
MessageInfo messageInfo)
Sends a message via this channel.
|
abstract <T> SctpChannel |
setOption(SctpSocketOption<T> name,
T value)
Sets the value of a socket option.
|
abstract SctpChannel |
shutdown()
Shutdown a connection without closing the channel.
|
abstract Set<SctpSocketOption<?>> |
supportedOptions()
Returns a set of the socket options supported by this channel.
|
abstract SctpChannel |
unbindAddress(InetAddress address)
Removes the given address from the bound addresses for the channel's
socket.
|
int |
validOps()
Returns an operation set identifying this channel's supported operations.
|
blockingLock, configureBlocking, implCloseChannel, implCloseSelectableChannel, implConfigureBlocking, isBlocking, isRegistered, keyFor, provider, register
register
begin, close, end, isOpen
protected SctpChannel(SelectorProvider provider)
provider
- The selector provider for this channelpublic static SctpChannel open() throws IOException
The new channel is unbound and unconnected.
UnsupportedOperationException
- If the SCTP protocol is not supportedIOException
- If an I/O error occurspublic static SctpChannel open(SocketAddress remote, int maxOutStreams, int maxInStreams) throws IOException
This is a convenience method and is equivalent to evaluating the following expression:
open().connect(remote, maxOutStreams, maxInStreams);
remote
- The remote address to which the new channel is to be connectedmaxOutStreams
- The number of streams that the application wishes to be able
to send to. Must be non negative and no larger than 65536
.
0
to use the endpoints default value.maxInStreams
- The maximum number of inbound streams the application is prepared
to support. Must be non negative and no larger than 65536
.
0
to use the endpoints default value.AsynchronousCloseException
- If another thread closes this channel
while the connect operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the connect operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusUnresolvedAddressException
- If the given remote address is not fully resolvedUnsupportedAddressTypeException
- If the type of the given remote address is not supportedSecurityException
- If a security manager has been installed
and it does not permit access to the given remote peerUnsupportedOperationException
- If the SCTP protocol is not supportedIOException
- If some other I/O error occurspublic abstract Association association() throws IOException
null
if the channel's socket is not
connected.ClosedChannelException
- If the channel is closedIOException
- If some other I/O error occurspublic abstract SctpChannel bind(SocketAddress local) throws IOException
This method is used to establish a relationship between the socket
and the local addresses. Once a relationship is established then
the socket remains bound until the channel is closed. This relationship
may not necesssarily be with the address local
as it may be removed
by unbindAddress
, but there will always be at least
one local address bound to the channel's socket once an invocation of
this method successfully completes.
Once the channel's socket has been successfully bound to a specific
address, that is not automatically assigned, more addresses
may be bound to it using bindAddress
, or removed
using unbindAddress
.
local
- The local address to bind the socket, or null
to
bind the socket to an automatically assigned socket addressAlreadyConnectedException
- If this channel is already connectedClosedChannelException
- If this channel is closedConnectionPendingException
- If a non-blocking connection operation is already in progress on this channelAlreadyBoundException
- If this channel is already boundUnsupportedAddressTypeException
- If the type of the given address is not supportedIOException
- If some other I/O error occursSecurityException
- If a security manager has been installed and its
checkListen
method denies
the operationpublic abstract SctpChannel bindAddress(InetAddress address) throws IOException
The given address must not be the wildcard
address.
The channel must be first bound using bind
before
invoking this method, otherwise NotYetBoundException
is thrown. The bind
method takes a SocketAddress
as its argument which typically
contains a port number as well as an address. Addresses subquently bound
using this method are simply addresses as the SCTP port number remains
the same for the lifetime of the channel.
Adding addresses to a connected association is optional functionality. If the endpoint supports dynamic address reconfiguration then it may send the appropriate message to the peer to change the peers address lists.
address
- The address to add to the bound addresses for the socketClosedChannelException
- If this channel is closedConnectionPendingException
- If a non-blocking connection operation is already in progress on
this channelNotYetBoundException
- If this channel is not yet boundAlreadyBoundException
- If this channel is already bound to the given addressIllegalArgumentException
- If address is null
or the wildcard
addressIOException
- If some other I/O error occurspublic abstract SctpChannel unbindAddress(InetAddress address) throws IOException
The given address must not be the wildcard
address.
The channel must be first bound using bind
before
invoking this method, otherwise NotYetBoundException
is thrown. If this method is invoked on a channel that does not have
address
as one of its bound addresses or that has only one
local address bound to it, then this method throws
IllegalUnbindException
.
The initial address that the channel's socket is bound to using bind
may be removed from the bound addresses for the channel's socket.
Removing addresses from a connected association is optional functionality. If the endpoint supports dynamic address reconfiguration then it may send the appropriate message to the peer to change the peers address lists.
address
- The address to remove from the bound addresses for the socketClosedChannelException
- If this channel is closedConnectionPendingException
- If a non-blocking connection operation is already in progress on
this channelNotYetBoundException
- If this channel is not yet boundIllegalArgumentException
- If address is null
or the wildcard
addressIllegalUnbindException
- If address
is not bound to the channel's socket. or
the channel has only one address bound to itIOException
- If some other I/O error occurspublic abstract boolean connect(SocketAddress remote) throws IOException
If this channel is in non-blocking mode then an invocation of this
method initiates a non-blocking connection operation. If the connection
is established immediately, as can happen with a local connection, then
this method returns true
. Otherwise this method returns
false
and the connection operation must later be completed by
invoking the finishConnect
method.
If this channel is in blocking mode then an invocation of this method will block until the connection is established or an I/O error occurs.
If a security manager has been installed then this method verifies
that its checkConnect
method permits connecting to the address and port number of the given
remote peer.
This method may be invoked at any time. If a send
or
receive
operation upon this channel is invoked while an
invocation of this method is in progress then that operation will first
block until this invocation is complete. If a connection attempt is
initiated but fails, that is, if an invocation of this method throws a
checked exception, then the channel will be closed.
remote
- The remote peer to which this channel is to be connectedtrue
if a connection was established, false
if
this channel is in non-blocking mode and the connection
operation is in progressAlreadyConnectedException
- If this channel is already connectedConnectionPendingException
- If a non-blocking connection operation is already in progress on
this channelClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel
while the connect operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the connect operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusUnresolvedAddressException
- If the given remote address is not fully resolvedUnsupportedAddressTypeException
- If the type of the given remote address is not supportedSecurityException
- If a security manager has been installed
and it does not permit access to the given remote peerIOException
- If some other I/O error occurspublic abstract boolean connect(SocketAddress remote, int maxOutStreams, int maxInStreams) throws IOException
This is a convience method and is equivalent to evaluating the following expression:
setOption(SctpStandardSocketOptions.SCTP_INIT_MAXSTREAMS, SctpStandardSocketOption.InitMaxStreams.create(maxInStreams, maxOutStreams)) .connect(remote);
The maxOutStreams
and maxInStreams
parameters
represent the maximum number of streams that the application wishes to be
able to send to and receive from. They are negotiated with the remote
peer and may be limited by the operating system.
remote
- The remote peer to which this channel is to be connectedmaxOutStreams
- Must be non negative and no larger than 65536
.
0
to use the endpoints default value.maxInStreams
- Must be non negative and no larger than 65536
.
0
to use the endpoints default value.true
if a connection was established, false
if
this channel is in non-blocking mode and the connection operation
is in progressAlreadyConnectedException
- If this channel is already connectedConnectionPendingException
- If a non-blocking connection operation is already in progress on
this channelClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel
while the connect operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the connect operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusUnresolvedAddressException
- If the given remote address is not fully resolvedUnsupportedAddressTypeException
- If the type of the given remote address is not supportedSecurityException
- If a security manager has been installed
and it does not permit access to the given remote peerIOException
- If some other I/O error occurspublic abstract boolean isConnectionPending()
true
if, and only if, a connection operation has been initiated
on this channel but not yet completed by invoking the
finishConnect()
methodpublic abstract boolean finishConnect() throws IOException
A non-blocking connection operation is initiated by placing a socket
channel in non-blocking mode and then invoking one of its connect
methods. Once the connection is established, or the attempt has
failed, the channel will become connectable and this method may
be invoked to complete the connection sequence. If the connection
operation failed then invoking this method will cause an appropriate
IOException
to be thrown.
If this channel is already connected then this method will not block and will immediately return true. If this channel is in non-blocking mode then this method will return false if the connection process is not yet complete. If this channel is in blocking mode then this method will block until the connection either completes or fails, and will always either return true or throw a checked exception describing the failure.
This method may be invoked at any time. If a send
or receive
operation upon this channel is invoked while an invocation of this
method is in progress then that operation will first block until this
invocation is complete. If a connection attempt fails, that is, if an
invocation of this method throws a checked exception, then the channel
will be closed.
true
if, and only if, this channel's socket is now
connectedNoConnectionPendingException
- If this channel is not connected and a connection operation
has not been initiatedClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel
while the connect operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the connect operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusIOException
- If some other I/O error occurspublic abstract Set<SocketAddress> getAllLocalAddresses() throws IOException
Set
if the channel's socket is not
boundClosedChannelException
- If the channel is closedIOException
- If an I/O error occurspublic abstract Set<SocketAddress> getRemoteAddresses() throws IOException
If the channel is connected to a remote peer that is bound to multiple addresses then it is these addresses that the channel's socket is connected.
Set
if the channel's socket is
not connectedClosedChannelException
- If the channel is closedIOException
- If an I/O error occurspublic abstract SctpChannel shutdown() throws IOException
Sends a shutdown command to the remote peer, effectively preventing
any new data from being written to the socket by either peer. Further
sends will throw ClosedChannelException
. The
channel remains open to allow the for any data (and notifications) to be
received that may have been sent by the peer before it received the
shutdown command. If the channel is already shutdown then invoking this
method has no effect.
NotYetConnectedException
- If this channel is not yet connectedClosedChannelException
- If this channel is closedIOException
- If some other I/O error occurspublic abstract <T> T getOption(SctpSocketOption<T> name) throws IOException
T
- The type of the socket option valuename
- The socket optionnull
may be
a valid value for some socket options.UnsupportedOperationException
- If the socket option is not supported by this channelClosedChannelException
- If this channel is closedIOException
- If an I/O error occursSctpStandardSocketOptions
public abstract <T> SctpChannel setOption(SctpSocketOption<T> name, T value) throws IOException
T
- The type of the socket option valuename
- The socket optionvalue
- The value of the socket option. A value of null
may be
a valid value for some socket options.UnsupportedOperationException
- If the socket option is not supported by this channelIllegalArgumentException
- If the value is not a valid value for this socket optionClosedChannelException
- If this channel is closedIOException
- If an I/O error occursSctpStandardSocketOptions
public abstract Set<SctpSocketOption<?>> supportedOptions()
This method will continue to return the set of options even after the channel has been closed.
public final int validOps()
SCTP channels support connecting, reading, and writing, so this
method returns (SelectionKey.OP_CONNECT
| SelectionKey.OP_READ
| SelectionKey.OP_WRITE
).
validOps
in class SelectableChannel
public abstract <T> MessageInfo receive(ByteBuffer dst, T attachment, NotificationHandler<T> handler) throws IOException
If a message or notification is immediately available, or if this
channel is in blocking mode and one eventually becomes available, then
the message or notification is returned or handled, respectively. If this
channel is in non-blocking mode and a message or notification is not
immediately available then this method immediately returns null
.
If this method receives a message it is copied into the given byte
buffer. The message is transferred into the given byte buffer starting at
its current position and the buffers position is incremented by the
number of bytes read. If there are fewer bytes remaining in the buffer
than are required to hold the message, or the underlying input buffer
does not contain the complete message, then an invocation of isComplete
on the returned MessageInfo
will return false
, and more invocations of this
method will be necessary to completely consume the messgae. Only
one message at a time will be partially delivered in any stream. The
socket option SCTP_FRAGMENT_INTERLEAVE
controls various aspects of what interlacing of
messages occurs.
If this method receives a notification then the appropriate method of
the given handler, if there is one, is invoked. If the handler returns
CONTINUE
then this method will try to
receive another message/notification, otherwise, if RETURN
is returned this method will return null
. If an uncaught exception is thrown by the handler it will be
propagated up the stack through this method.
This method may be invoked at any time. If another thread has
already initiated a receive operation upon this channel, then an
invocation of this method will block until the first operation is
complete. The given handler is invoked without holding any locks used
to enforce the above synchronization policy, that way handlers
will not stall other threads from receiving. A handler should not invoke
the receive
method of this channel, if it does an
IllegalReceiveException
will be thrown.
T
- The type of the attachmentdst
- The buffer into which message bytes are to be transferredattachment
- The object to attach to the receive operation; can be
null
handler
- A handler to handle notifications from the SCTP stack, or null
to ignore any notifications.MessageInfo
, null
if this channel is in
non-blocking mode and no messages are immediately available or
the notification handler returns RETURN
after handling a notificationClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel
while the read operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the read operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusNotYetConnectedException
- If this channel is not yet connectedIllegalReceiveException
- If the given handler invokes the receive
method of this
channelIOException
- If some other I/O error occurspublic abstract int send(ByteBuffer src, MessageInfo messageInfo) throws IOException
If this channel is in non-blocking mode and there is sufficient room
in the underlying output buffer, or if this channel is in blocking mode
and sufficient room becomes available, then the remaining bytes in the
given byte buffer are transmitted as a single message. Sending a message
is atomic unless explicit message completion SCTP_EXPLICIT_COMPLETE
socket option is enabled on this channel's socket.
The message is transferred from the byte buffer as if by a regular
write
operation.
The bytes will be written to the stream number that is specified by
streamNumber
in the given messageInfo
.
This method may be invoked at any time. If another thread has already initiated a send operation upon this channel, then an invocation of this method will block until the first operation is complete.
src
- The buffer containing the message to be sentmessageInfo
- Ancillary data about the message to be sentInvalidStreamException
- If streamNumner
is negative or greater than or equal to
the maximum number of outgoing streamsClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel
while the read operation is in progressClosedByInterruptException
- If another thread interrupts the current thread
while the read operation is in progress, thereby
closing the channel and setting the current thread's
interrupt statusNotYetConnectedException
- If this channel is not yet connectedIOException
- If some other I/O error occurs
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