An SCTP multi channel supports many associations on a single socket. + * An {@code SctpMultiChannel} is created by invoking the + * {@link #open open} method of this class. A newly-created channel is open but + * not yet bound. An attempt to invoke the {@link #receive receive} method of an + * unbound channel will cause the {@link NotYetBoundException} + * to be thrown. An attempt to invoke the {@link #send send} method of an + * unbound channel will cause it to first invoke the {@link #bind bind} method. + * The address(es) that the channel's socket is bound to can be retrieved by + * calling {@link #getAllLocalAddresses getAllLocalAddresses}. + * + *
Messages may be sent and received without explicitly setting up an + * association with the remote peer. The channel will implicitly setup + * a new association whenever it sends or receives a message from a remote + * peer if there is not already an association with that peer. Upon successful + * association setup, an {@link AssociationChangeNotification + * association changed} notification will be put to the SCTP stack with its + * {@code event} parameter set to {@link + * AssociationChangeNotification.AssocChangeEvent#COMM_UP + * COMM_UP}. This notification can be received by invoking {@link #receive + * receive}. + * + *
Socket options are configured using the + * {@link #setOption(SctpSocketOption,Object,Association) setOption} method. An + * {@code SctpMultiChannel} supports the following options: + *
+ *+ * Additional (implementation specific) options may also be supported. The list + * of options supported is obtained by invoking the {@link #supportedOptions() + * supportedOptions} method. + * + *+ * + * + *
+ *+ * + * + * + *Option Name + *Description + *+ * + *{@link SctpStandardSocketOptions#SCTP_DISABLE_FRAGMENTS + * SCTP_DISABLE_FRAGMENTS} + *Enables or disables message fragmentation + *+ * + *{@link SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE + * SCTP_EXPLICIT_COMPLETE} + *Enables or disables explicit message completion + *+ * + *{@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE + * SCTP_FRAGMENT_INTERLEAVE} + *Controls how the presentation of messages occur for the message + * receiver + *+ * + *{@link SctpStandardSocketOptions#SCTP_INIT_MAXSTREAMS + * SCTP_INIT_MAXSTREAMS} + *The maximum number of streams requested by the local endpoint during + * association initialization + *+ * + *{@link SctpStandardSocketOptions#SCTP_NODELAY SCTP_NODELAY} + *Enables or disable a Nagle-like algorithm + *+ * + *{@link SctpStandardSocketOptions#SCTP_PRIMARY_ADDR + * SCTP_PRIMARY_ADDR} + *Requests that the local SCTP stack use the given peer address as the + * association primary + *+ * + *{@link SctpStandardSocketOptions#SCTP_SET_PEER_PRIMARY_ADDR + * SCTP_SET_PEER_PRIMARY_ADDR} + *Requests that the peer mark the enclosed address as the association + * primary + *+ * + *{@link SctpStandardSocketOptions#SO_SNDBUF + * SO_SNDBUF} + *The size of the socket send buffer + *+ * + *{@link SctpStandardSocketOptions#SO_RCVBUF + * SO_RCVBUF} + *The size of the socket receive buffer + *+ * + * + *{@link SctpStandardSocketOptions#SO_LINGER + * SO_LINGER} + *Linger on close if data is present (when configured in blocking mode + * only) + *
SCTP multi channels are safe for use by multiple concurrent threads. + * They support concurrent sending and receiving, though at most one thread may be + * sending and at most one thread may be receiving at any given time. + * + * @since 1.7 + */ +public abstract class SctpMultiChannel + extends AbstractSelectableChannel +{ + /** + * Initializes a new instance of this class. + * + * @param provider + * The selector provider for this channel + */ + protected SctpMultiChannel(SelectorProvider provider) { + super(provider); + } + + /** + * Opens an SCTP multi channel. + * + *
The new channel is unbound. + * + * @return A new SCTP multi channel + * + * @throws UnsupportedOperationException + * If the SCTP protocol is not supported + * + * @throws IOException + * If an I/O error occurs + */ + public static SctpMultiChannel open() throws + IOException { + return new sun.nio.ch.sctp.SctpMultiChannelImpl((SelectorProvider)null); + } + + /** + * Returns the open associations on this channel's socket. + * + *
Only associations whose {@link AssociationChangeNotification.AssocChangeEvent#COMM_UP + * COMM_UP} association change event has been received are included + * in the returned set of associations. Associations for which a + * {@link AssociationChangeNotification.AssocChangeEvent#COMM_LOST COMM_LOST} or {@link + * AssociationChangeNotification.AssocChangeEvent#SHUTDOWN SHUTDOWN} association change + * event have been receive are removed from the set of associations. + * + *
The returned set of associations is a snapshot of the open
+ * associations at the time that this method is invoked.
+ *
+ * @return A {@code Set} containing the open associations, or an empty
+ * {@code Set} if there are none.
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract Set This method is used to establish a relationship between the socket
+ * and the local address. Once a relationship is established then
+ * the socket remains bound until the channel is closed. This relationship
+ * may not necesssarily be with the address {@code local} as it may be removed
+ * by {@link #unbindAddress 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 {@link #bindAddress bindAddress}, or removed
+ * using {@link #unbindAddress unbindAddress}.
+ *
+ * The backlog parameter is the maximum number of pending connections on
+ * the socket. Its exact semantics are implementation specific. An implementation
+ * may impose an implementation specific maximum length or may choose to ignore
+ * the parameter. If the backlog parameter has the value {@code 0}, or a negative
+ * value, then an implementation specific default is used.
+ *
+ * @param local
+ * The local address to bind the socket, or {@code null} to
+ * bind the socket to an automatically assigned socket address
+ *
+ * @param backlog
+ * The maximum number of pending connections
+ *
+ * @return This channel
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws java.nio.channels.AlreadyBoundException
+ * If this channel is already bound
+ *
+ * @throws java.nio.channels.UnsupportedAddressTypeException
+ * If the type of the given address is not supported
+ *
+ * @throws SecurityException
+ * If a security manager has been installed and its {@link
+ * java.lang.SecurityManager#checkListen(int) checkListen} method
+ * denies the operation
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract SctpMultiChannel bind(SocketAddress local,
+ int backlog)
+ throws IOException;
+
+ /**
+ * Binds the channel's socket to a local address and configures the socket
+ * to listen for connections.
+ *
+ * This method works as if invoking it were equivalent to evaluating the
+ * expression:
+ * The given address must not be the {@link
+ * java.net.InetAddress#isAnyLocalAddress wildcard} address.
+ * The channel must be first bound using {@link #bind bind} before
+ * invoking this method, otherwise {@link NotYetBoundException} is thrown.
+ * The {@link #bind bind} method takes a {@code 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.
+ *
+ * New associations setup after this method successfully completes
+ * will be associated with the given address. Adding addresses to existing
+ * associations 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.
+ *
+ * @param address
+ * The address to add to the bound addresses for the socket
+ *
+ * @return This channel
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws NotYetBoundException
+ * If this channel is not yet bound
+ *
+ * @throws java.nio.channels.AlreadyBoundException
+ * If this channel is already bound to the given address
+ *
+ * @throws IllegalArgumentException
+ * If address is {@code null} or the {@link
+ * java.net.InetAddress#isAnyLocalAddress wildcard} address
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract SctpMultiChannel bindAddress(InetAddress address)
+ throws IOException;
+
+ /**
+ * Removes the given address from the bound addresses for the channel's
+ * socket.
+ *
+ * The given address must not be the {@link
+ * java.net.InetAddress#isAnyLocalAddress wildcard} address.
+ * The channel must be first bound using {@link #bind bind} before
+ * invoking this method, otherwise {@link NotYetBoundException} is thrown.
+ *
+ * If this method is invoked on a channel that does
+ * not have {@code address} as one of its bound addresses, or that has only
+ * one local address bound to it, then this method throws
+ * {@link IllegalUnbindException}.
+ *
+ * The initial address that the channel's socket is bound to using
+ * {@link #bind bind} may be removed from the bound addresses for the
+ * channel's socket.
+ *
+ * New associations setup after this method successfully completes
+ * will not be associated with the given address. Removing addresses from
+ * existing associations 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.
+ *
+ * @param address
+ * The address to remove from the bound addresses for the socket
+ *
+ * @return This channel
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws NotYetBoundException
+ * If this channel is not yet bound
+ *
+ * @throws IllegalUnbindException
+ * {@code address} is not bound to the channel's socket, or the
+ * channel has only one address bound to it
+ *
+ * @throws IllegalArgumentException
+ * If address is {@code null} or the {@link
+ * java.net.InetAddress#isAnyLocalAddress wildcard} address
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract SctpMultiChannel unbindAddress(InetAddress address)
+ throws IOException;
+
+ /**
+ * Returns all of the socket addresses to which this channel's socket is
+ * bound.
+ *
+ * @return All the socket addresses that this channel's socket is
+ * bound to, or an empty {@code Set} if the channel's socket is not
+ * bound
+ *
+ * @throws ClosedChannelException
+ * If the channel is closed
+ *
+ * @throws IOException
+ * If an I/O error occurs
+ */
+ public abstract Set Note that some options are retrieved on the channel's socket,
+ * therefore the {@code association} parameter is not applicable and will be
+ * ignored if given. However, if the option is association specific then the
+ * association must be given.
+ *
+ * @param Note that some options are retrieved on the channel's socket,
+ * therefore the {@code association} parameter is not applicable and will be
+ * ignored if given. However, if the option is association specific then the
+ * association must be given.
+ *
+ * @param This method will continue to return the set of options even after the
+ * channel has been closed.
+ *
+ * @return A set of the socket options supported by this channel
+ */
+ public abstract Set SCTP multi channels support reading, and writing, so this
+ * method returns
+ * {@code (}{@link SelectionKey#OP_READ} {@code |} {@link
+ * SelectionKey#OP_WRITE}{@code )}. 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 {@code null}.
+ *
+ * If this method receives a message it is copied into the given byte
+ * buffer and an {@link MessageInfo} is returned.
+ * 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 {@link
+ * MessageInfo#isComplete isComplete} on the returned {@code
+ * MessageInfo} will return {@code 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 {@link SctpStandardSocketOptions#SCTP_FRAGMENT_INTERLEAVE
+ * 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 {@link
+ * HandlerResult#CONTINUE CONTINUE} then this method will try to receive another
+ * message/notification, otherwise, if {@link HandlerResult#RETURN RETURN} is returned
+ * this method will return {@code null}. If an uncaught exception is thrown by the
+ * handler it will be propagated up the stack through this method.
+ *
+ * If a security manager has been installed then for each new association
+ * setup this method verifies that the associations source address and port
+ * number are permitted by the security manager's {@link
+ * java.lang.SecurityManager#checkAccept(String,int) checkAccept} 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 {@code receive} method of this channel, if it does an
+ * {@link IllegalReceiveException} will be thrown.
+ *
+ * @param If this channel is unbound then this method will invoke {@link
+ * #bind(SocketAddress, int) bind(null, 0)} before sending any data.
+ *
+ * If there is no association existing between this channel's socket
+ * and the intended receiver, identified by the address in the given messageInfo, then one
+ * will be automatically setup to the intended receiver. This is considered
+ * to be Implicit Association Setup. Upon successful association setup, an
+ * {@link AssociationChangeNotification association changed}
+ * notification will be put to the SCTP stack with its {@code event} parameter set
+ * to {@link AssociationChangeNotification.AssocChangeEvent#COMM_UP COMM_UP}
+ * . This notification can be received by invoking {@link #receive
+ * receive}.
+ *
+ * If this channel is in blocking mode, there is sufficient room in the
+ * underlying output buffer, then the remaining bytes in the given byte
+ * buffer are transmitted as a single message. Sending a message
+ * is atomic unless explicit message completion {@link
+ * SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE SCTP_EXPLICIT_COMPLETE}
+ * socket option is enabled on this channel's socket.
+ *
+ * If this channel is in non-blocking mode, there is sufficient room
+ * in the underlying output buffer, and an implicit association setup is
+ * required, then the remaining bytes in the given byte buffer are
+ * transmitted as a single message, subject to {@link
+ * SctpStandardSocketOptions#SCTP_EXPLICIT_COMPLETE SCTP_EXPLICIT_COMPLETE}.
+ * If for any reason the message cannot
+ * be delivered an {@link AssociationChangeNotification association
+ * changed} notification is put on the SCTP stack with its {@code event} parameter set
+ * to {@link AssociationChangeNotification.AssocChangeEvent#CANT_START CANT_START}.
+ *
+ * The message is transferred from the byte buffer as if by a regular
+ * {@link java.nio.channels.WritableByteChannel#write(java.nio.ByteBuffer)
+ * write} operation.
+ *
+ * If a security manager has been installed then for each new association
+ * setup this method verifies that the given remote peers address and port
+ * number are permitted by the security manager's {@link
+ * java.lang.SecurityManager#checkConnect(String,int) checkConnect} method.
+ *
+ * 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.
+ *
+ * @param buffer
+ * The buffer containing the message to be sent
+ *
+ * @param messageInfo
+ * Ancillary data about the message to be sent
+ *
+ * @return The number of bytes sent, which will be either the number of
+ * bytes that were remaining in the messages buffer when this method
+ * was invoked or, if this channel is non-blocking, may be zero if
+ * there was insufficient room for the message in the underlying
+ * output buffer
+ *
+ * @throws InvalidStreamException
+ * If {@code streamNumber} is negative, or if an association already
+ * exists and {@code streamNumber} is greater than the maximum number
+ * of outgoing streams
+ *
+ * @throws java.nio.channels.ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws java.nio.channels.AsynchronousCloseException
+ * If another thread closes this channel
+ * while the read operation is in progress
+ *
+ * @throws java.nio.channels.ClosedByInterruptException
+ * 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 status
+ *
+ * @throws SecurityException
+ * If a security manager has been installed and it does not permit
+ * new associations to be setup with the messages's address
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract int send(ByteBuffer buffer, MessageInfo messageInfo)
+ throws IOException;
+
+ /**
+ * Branches off an association.
+ *
+ * An application can invoke this method to branch off an association
+ * into a separate channel. The new bound and connected {@link SctpChannel}
+ * will be created for the association. The branched off association will no
+ * longer be part of this channel.
+ *
+ * This is particularly useful when, for instance, the application
+ * wishes to have a number of sporadic message senders/receivers remain
+ * under the original SCTP multi channel but branch off those
+ * associations carrying high volume data traffic into their own
+ * separate SCTP channels.
+ *
+ * @param association
+ * The association to branch off
+ *
+ * @return The {@code SctpChannel}
+ *
+ * @throws java.nio.channels.ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public abstract SctpChannel branch(Association association)
+ throws IOException;
+}
+ *
+ * @param local
+ * The local address to bind the socket, or {@code null} to
+ * bind the socket to an automatically assigned socket address
+ *
+ * @return This channel
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ *
+ * @throws java.nio.channels.AlreadyBoundException
+ * If this channel is already bound
+ *
+ * @throws java.nio.channels.UnsupportedAddressTypeException
+ * If the type of the given address is not supported
+ *
+ * @throws SecurityException
+ * If a security manager has been installed and its {@link
+ * java.lang.SecurityManager#checkListen(int) checkListen} method
+ * denies the operation
+ *
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ public final SctpMultiChannel bind(SocketAddress local)
+ throws IOException {
+ return bind(local, 0);
+ }
+
+ /**
+ * Adds the given address to the bound addresses for the channel's
+ * socket.
+ *
+ *
+ * bind(local, 0);
+ *